Blog
Using a Ruuvitag to Trigger a Cooling Fan in your Electrical System with a Victron Cerbo GX
We often get asked about ventilation and fans to keep an electrical system cool under loads. After all these power system components can get pretty warm when running AND they’re very often tucked away under a bed or inside a cabinet. Also, if Victron Energy equipment gets too hot, they start “derating” which basically means that the ability of the device to perform at it’s highest performance is decreased in relation to the temperature. For instance, if you have a MultiPlus 12/3000/120 inverter/charger that is rated for about 2,400 watts at 77 degrees Fahrenheit, and if the temp goes up to 104 degrees, the output is “derated” to 2,200 watts. Below is a table taken from the spec sheet for the unit that illustrates this pretty clearly. Or, if you really want to nerd out, Victron has this white paper. Similar “derating” happens on other devices such as MPPT solar controllers or DC-DC chargers, etc. So, what to do for ventilation? The simple answer is to add as much “passive” ventilation as you can and try to have at least two vent locations to allow the air to flow through the area. There are lots of ways to add vents to cabinets that I don’t think we need to cover here! Anyway, there is an online store called Amazon.com (I know, weird name), that sells a variety of things including these circular vents that we’ve used often. But, practically speaking, sometimes, passive cooling just isn’t going to do the trick so we wanted to share how to add some “active cooling” with computer fans that only turn on when the temperature in your electrical system area reaches a particular temperature. To do this we’ll use a Ruuvitag (wireless, Bluetooth temp/humidity/air pressure sensor) and the built-in relay inside a Victron Energy Cerbo GX. Connecting a Ruuvitag To A Victron Cerbo GX Ruuvitags are small, affordable sensors that are incredibly easy to deploy since they can communicate wirelessly with a Victron Cerbo GX. They come in three versions. We’ll be discussing the baseline, 4-in-one Ruuvitag (temperature, humidity, air pressure, and motion). There is also a water-resistant 3-in-one version (temperature, humidity, and motion) as well as a fully waterproof (submersible) 2-in-one version (temperature and motion only). In our vans, we like to put these Ruuvitags in various places – one in the main living space, another near the power system, one outside, and sometimes one in the fridge too! Victron Energy recommends using a USB to Bluetooth “dongle” to increase the Bluetooth signal reach on the Cerbo GX. These are quite inexpensive (around $10) and make a big difference. We have a few recommended/tested options on the product page (in the description). To add a Ruuvitag to your system, start by pulling the plastic strip out from the side. This will turn the Ruuvitag on by allowing the battery to connect to the circuit board. Next, on the Cerbo GX, navigate to “menu -> settings -> Bluetooth” and ensure that it’s “enabled”. Then go to “menu -> settings -> I/O -> Bluetooth sensors” and make sure that they are enabled as well. Once these two settings are enabled, you should see the Ruuvitag appear on the I/O screen or on the first menu screen. You can navigate to the main menu screen by going back to “pages” and then pressing “menu” again or simply pressing the “back” button a few times to get to the main menu. On this main menu, you should see the Ruuvitag appear as something along the lines of “generic temperature sensor”. If you press on this device in the menu, you’ll open the Ruuvitag’s menu. You can check that you’re interacting with the right device by confirming that the “product” is a “Ruuvitag”. Next, you can give the Ruuvitag an appropriate name by navigating to the “device” option and then pressing on “name” which will launch a keyboard so you can name it something such as “Power System”. Now, if you haven’t already, you might want to switch the temperature units from Celsius to Fahrenheit (menu -> settings -> display & language -> units). If you don’t see this option, you’ll probably need to upgrade your firmware on the Cerbo GX to the latest version of Venus OS (menu -> settings -> firmware -> online updates). The same goes for if the Ruuvitags are not being “seen” by your Cerbo GX – updating the firmware will likely fix that as well. It’s worth mentioning that having temperature data on the Cerbo GX is pretty darn useful in other scenarios as well. For instance, if you have your system configured to send data to Victron’s free cloud service called VRM, you can get notifications pushed to you via email. Imagine if you’re traveling with a pet and you want to be notified if the interior temp goes above 85 degrees. Adding A Temperature Triggered Fan With a Cerbo GX Now that we have a temperature sensor with the Ruuvitag, we’ll dive into wiring up a fan (or multiple fans) to one of the relays on the Victron Energy Cerbo GX. You can use pretty much any 12-volt DC-powered fan and even combine multiple fans/loads running off the relay. In my van, I choose these fans and paired them up with these vents. The one limitation to be aware of is that the relay is only rated for 6 amps at up to 30 volts DC. However, most computer fans use very little power. There are two built-in relays on the Cerbo GX. Relay #1 has a lot more options as you can see in the screenshot below comparing the “function” choices for relay 1 and relay 2. For this reason, we recommend that you use relay 2 for this kind of “temperature” trigger so that relay 1 can remain available for other functions such as a generator start/stop, etc. Start by opening up the relay 2 options on the Cerbo GX (menu -> settings -> relay -> function (relay 2)). Then choose “temperature” from this menu as illustrated on the right side of the image above. Now, if you go back one menu with the “back” button (arrow in the very top left portion of the screen), you’ll see a new menu called “temperature control rules”. Below is a screenshot of this menu showing the various Ruuvitags in my van (temperature sensors) connected to the Cerbo GX. The next step is to choose which temperature sensor/Ruuvitag should be used as the relay triggering sensor. In my case, that’s the “Power Cabinet Temp”. Press on that sensor to open its menu which looks like the following. This is where you’ll configure the specific conditions where you want the fan(s) to turn on and off which are the “activation value” and the “deactivation value” respectively. Notice that there is a way to set two “conditions”. In our example, we’ll only use one. I have my fan set to come on at 90 degrees and to turn off at 84 degrees. If the “activation value” for “condition 1” has been met (temp inside the power cabinet is above 90 degrees), as was the case when this screenshot was taken, the “condition 1” will show as “active”. If not, it will show as “inactive”. Configure your activation and deactivation values to your liking – you can always return to this menu and change the settings! Wiring The Relay The last step is actually wiring up the relay. The Cerbo GX comes with a bunch of black terminal blocks that can plug into the bottom of the device for tank monitoring, relays, etc. So, you’ll need one of those. The illustration below outlines the wiring of the relay. The post discusses using relay 2 instead but the wiring illustration shows relay 1. The great thing about the terminal blocks is that they can be remove for ease of wiring and also be swapped from one relay port to the other. I think the illustration describes the wiring better than I can do in words, but basically, you’ll supply 12 volt DC positive from your system – likely from your 12 volt load center/fuse box, which will connect up to the relay’s “common” connection. The 12 volt DC negative wire can go directly to the fan/load since only the positive side of the circuit will be controlled by the relay. Then you’ll wire the NO (normally open) connection to the fan/load’s DC positive terminals. And that’s it! Now you can test the relay by adjusting the “activation” values to be close to the ambient temperatures and/or carefully heat up the Ruuvitag with a heat gun until the activation value temperature is met and you should see the relay come on (contacts close) to power your fan(s)/load!
Learn more
Accurate Tank Monitoring with a Cerbo GX and SeeLevel
Note: we sell a full kit with all the components you need to use the SeeLevel tank monitoring system with a Victron Energy Cerbo GX in our store. Save yourself time and headaches! Background I’ve been a big fan of SeeLevel tank monitoring products for a long time now. I used them in my first van conversion back in 2016 and a few projects since then. I’m also a really big fan of the Victron Energy Cerbo GX and most of our power system installations include one. So, you can imagine how excited I was when Victron Energy released version 2.90 of the VenusOS that runs the Cerbo GX including support for SeeLevel sensors! For a van nerd like me, this opened the door to using two of my favorite products together, and this post details what I’ve learned and how to do it. This paragraph may be one of the nerdiest things you’ll ever read… I own that! The best thing about the SeeLevel system is how easy it is to install. Traditional resistive sensors require a hole to be drilled into your tank and tend to give inaccurate results over time. The SeeLevel sensors simply stick onto the outside of your tank and, since they’re external, they don’t get fouled up by the liquids in the tank (particularly grey and black tanks). One important note is that SeeLevel sensors (senders) don’t work on metal tanks (must be plastic). How They Work The illustration below describes how the SeeLevel monitoring system works. There is also this video. What You’ll Need Note: we sell a complete kit with everything you need for this system in our store. As always, we appreciate your support. A SeeLevel 709-N2K-PM. It’s very important that you get the N2K (NMEA2000 version). There are some RV-C versions that can work with the Cerbo GX but, at the time we’re publishing this blog post, they prevent anything else from working on the VE.Can bus such as other Victron Energy components like a BMS, etc. This product is the actual “panel” that looks like the one shown in the illustration above. It’s designed to mount onto a wall in your rig for checking the levels of your tanks. So, you can locate that in a convenient location or choose to “hide it away” next to your Cerbo GX if you only want to reference the Cerbo GX screen for tank levels. There is a newer product from SeeLevel that’s called the Soul which does not come with the panel and supports up to 7x tanks. However, the Soul cannot be sold to DIY customers – according to the manufacturer (Garnet) that is an “OEM-only” product. Also, it speaks “RV-C” over the CAN network instead of NMEA2000 which is a problem (see above). One or more sensors/senders. You’ll want one sensor per tank in your system with a maximum of 3x (fresh water, grey water and black water). For instance, if you only have a fresh and grey tank, you’ll likely only need two sensors. The sensors come in the following options: The 710-ES2 sensor can monitor tanks between 5.5″ and 14″ tall The 710-AR sensor can monitor tanks between 3.5″ and 10.5″ tall If you have a very “tall” tank you can combine two sensors which is detailed in the manua; and sender/sensor guide. A Victron Energy Cerbo GX with an open/available VE.Can port CAN data cable. See details on how to make this cable below. Parts you’ll need for to make this cable are listed below. A standard UTP/network cable with RJ45 connectors. The CAN connection for the Cerbo GX is on the back of that panel so the location of the panel (and the distance to the Cerbo GX in your system) will determine how long of a cable you need. A 120 Ohm resistor, 1/4 W, 5%. 3M 37104, 4-pin connector. You should consider ordering a few extra of these since it’s kind of tricky to get all the wires into the connector without them pulling out. Creating a NMEA2000 “Network”Connecting the SeeLevel Panel to the Cerbo GX If you happen to already have a NMEA2000 network in your rig you’ll approach this very differently. But, for the sake of this post, we’ll assume you don’t. So, we’ll be making a cable that connects the 4-pin connector on the back of the SeeLevel panel to a VE.Can port on the Cerbo GX in the form of a NMEA2000 (N2K) “network”. The parts you’ll need for this are detailed just above. Note: we include a pre-made cable for this in our kit if you don’t want to mess with this yourself! To start, cut off one of the RJ45 connectors from the UTP/network cable you’ll be using. Then strip away about an inch of the outer insulation from that end. You should see 4 “pairs” of wires twisted together (8x total wires). The “pairs” are various colors and each “pair” has a “solid” and a “striped” wire. You’ll want to identify the brown and green pairs – you will keep those and cut away the others (orange and blue pairs). There may also be some plastic material inside with the wires than can be removed. At this point, you should have four remaining wires: brown solid, brown striped, green solid, and green striped. These will be wired up to the 3M 37104, 4-pin connector as shown in the illustration below. Untwist each of the 4x wires to separate them and then gently insert them into the correct location in the connector. Then, insert one end of the resistor into pin #2 and the other into pin #3. It can be tricky to get all these wires into the right “slots” and prevent them from pulling out. Take your time and only move onto the “crimping” step when you’re confident everything is aligned correctly. Now finish up the cable by crimping the connector. You can buy a special crimping tool to crimp this connector but we’ve found that a pair of pliers used to pinch the top of the connector down onto the bottom works fine. Attaching Sensors and Wiring Them to Panel The first thing you’ll want to do is “program” each sensor so that it can be assigned to monitor a specific tank (fresh, grey, black). Typically this is as simple as cutting away the correct “tab” at the top of the sensor. For instance, if the sensor will be used to monitor a grey water tank, you would cut away the tab labeled GRY. For fresh water tanks, you leave the sensor as-is and don’t cut any of the tabs. If your tank is so tall that you need two sensors to cover its height, these tabs are also part of how you’d “program” which sensor is the “top” and which was the “bottom”. Finally, if you have more than one tank of a particular type (i.e.: more than one fresh water tank for example), these tabs enable you to differentiate those as well. All of this is detailed in the tank senders manual but the illustration below is a simplified version that is likely to apply to most van builders. Next, you’ll attach the sensor(s) to your tank(s). This is super easy. Just peel away the backing on the sensor and attach it to the tank with its adhesive strip. Be sure that you’ve cleaned the tank surface where you’ll be sticking the sensor. Ideally, you want about 1/2″ of space below the sensor on the bottom of the tank and 1/2″ of space above the sensor on the top of the tank. Be sure there are no metal objects near the sensor (within 3-5 inches). I once had a SeeLevel sensor reporting funky values and traced it back to a metal strap that was securing the tank. Moving the sensor a few inches away solved the problem. If a sensor does not fit the full height of the tank, you can “justify” the sensor’s location to be either closer to the top or bottom, depending on the type of liquid. For fresh water tanks, it’s best to have them closer to the bottom since you’re typically most concerned about running out of fresh water, and for waste tanks (grey/black), you want them closer to the top since you don’t want to overfill those tanks. You can also pair two sensors together for particularly tall tanks as we mentioned above and as detailed in the manual. If a sensor is too tall, you can shorten it by cutting off a portion of its length. You simply cut the sensor at one of the spaces between the “pads”. Note that you must leave at least 3x pads at the top of the sensor. The top is where the wires are attached. This is all illustrated in the image below. If the tank is outside the rig, you can protect it from the weather by coating it with rubberized undercoating. SeeLevel specifically recommends 3M 03584 Professional Grade Rubberized Undercoating or Gravel Guard Rocker Guard Coating By Dominion Sure Seal. We’ve tested the 3M product and it works well. We tested another undercoating product from a local hardware store and it damaged the sensor! Once the sensor(s) have been placed the wiring is also quite simple. There is a white connector included with the system that plugs into the white connection on the back of the panel. It has the following 3x bare wires. The red wire should be connected to a circuit-protected 12 volt DC positive supply (likely to your 12 volt load center). The black wire should be connected to your 12 volt DC negative supply (also likely your 12 volt load center). This one will be “split” to each sensor. We recommend a Wago, lever lock connectors for this. The blue wire is also split to each sensor. Each sensor has a short, blue, and black wire that can be extended to the required length with additional wire. All of the black wires should be tied together and all the blue wires should be tied together which is illustrated below. Configuring the Sensors At this point, you’ll want to power up the SeeLevel panel and go into the settings to configure each tank. The SeeLevel panel we’re discussing in this post (and that we sell in our store) can monitor the “standard” 3x tank types found in vans/RVs (fresh, grey, and black). If you don’t have all three types, you can simply connect and configure the ones you need. In other words, if you only have a fresh and grey tank, it will ignore the “black” (“waste”) tank. Each tank needs at least one sensor/sender but, as mentioned above, you can use 2x sensors/senders on taller tanks in order to cover the full height of the tank(s). Using the Tank Menus This is confusing and you’ll probably have to read it a few times and then fumble around as well. I tried to write it as clearly as I can but it’s just not intuitive! To enter a specific tank’s menu, you press (and hold) the tank type and then simultaneously press the “batt” button. For instance, if you want to enter the black tank’s menu, press (and hold) the “black” button and then press (and hold) the “batt” button. Once you’re in the menu, the length of time you continue holding both buttons determines which option/setting you’ll be interacting with as follows. Releasing the two buttons selects that menu and, when you’re done interacting with the menu you press the “batt” button again to save and exit. Buttons held for 1 second: diagnostic information (diA shown on panel) Buttons held for 5 seconds: alarm options (ALr shown on panel) Buttons held for 10 seconds: connected sender/sensors (last two digits of r5 shown on panel) Buttons held for 15 seconds: tank capacity (last two digits of cA shown on panel) First, disable any tank types that you don’t have. For instance, if you don’t have a black tank, remove it by entering that tank’s “connected sender/sensors” menu (a ten-second press, see above). Once in the menu, press the “fresh” button to cycle through the options: SE0 = no tanks of this type (use this to disable this type of tank) SE1 = a single tank of this type (use this to reenable this type of tank if you’re adding it) SE2 = two tanks of this type Use the “batt” button to save and exit. Next, configure the capacity of each of your tanks. For each tank, enter that tank’s “tank capacity” menu (a 15-second press, see above). Once in the menu, you’ll see a number that represents the tank’s capacity in gallons. Use the “fresh” button to increase the number and the “grey” button to decrease. Use the “batt” button to save and exit. If you have already connected your SeeLevel panel to the Cerbo GX you’ll need to reboot it. Any changes to the SeeLevel configuration require a reboot of the Cerbo GX to be read correctly. Configuring the Cerbo GX Yay! It’s time to plug the SeeLevel panel into the Cerbo GX. The funky crimped side that you just made goes into the back of the SeeLevel and the RJ45 connector plugs into an available VE.Can port. Be sure to use a terminator in the unused VE.Can ports. They look like a connector without a cable (photo) and a few of them would have been included with your Cerbo GX. I recommend rebooting the Cerbo GX at this point. When it comes online, you should see a few things changed. The tank(s) should appear on the touch screen “pages” and in the menu as shown below. Note that you should only see the tanks that have one or more sensors configured. In other words, if you followed our example earlier and disabled the black tank monitoring by setting the number of connected black tank sensors to zero, you should not see it appear on the Cerbo. If you do, you can revisit those settings. You can now enter the settings for each of the tank sensors by pressing on its name from the Cerbo GX menu this should show you more information about the tank and its status. From there, if you press on “setup”, you see the tank’s capacity, fluid type, and volume unit as shown below. You can change the volume unit to gallons and then verify that what’s shown on the Cerbo GX matches the capacity you set when configuring the SeeLevel which is 30 gallons in our example image. Each “type” of tank that is enabled on the SeeLevel panel should come across on the Cerbo GX with a similar name: “fresh water”, “waste water” for grey tanks, and “black water (sewage)” for black tanks. As far as we can tell you cannot customize the name but you could use the “fluid type” menu on the Cerbo GX to change the label to something else. Finally, you may want to enable the “tanks overview” page/screen on the Cerbo GX that is shown on the right side of the image below. To do so, enter the menu on the Cerbo GX, navigate to “settings” and then “display & language”. This is shown on the left side of the image below. Other Resources SeeLevel II Tank Sender Manual Ross Lukeman's Video
Learn more
12-Volt Secondary Alternator Example Power System - Nations, Wakespeed & Victron
Jump To Example Wiring Diagram This post details how to install a powerful, super off-grid capable camper van power system that uses a Nations secondary alternator paired with a Wakespeed WS500 regulator, Victron Energy Smart lithium batteries, and a bunch of other Victron Energy equipment! This is part of a series of posts and we highly encourage you to check out the others! This post is an introduction to a 12-volt secondary alternator electrical system and why you might want to consider one for your van, RV, or other mobile application as well as a FREE example wiring diagram (see below) using Victron batteries and other gear that corresponds to our best price product bundle which makes it easy to get you everything you need at an awesome price! A video tour of this system installed into a Sprinter van that shows how it works. A technical deep dive video about the Wakespeed WS500 alternator regulator used in these systems. Other blog posts about a 24-volt secondary alternator power system and a 48-volt secondary alternator power system that also includes a FREE example wiring diagram and product bundle. Since this post was first written in September of 2021 we’ve helped many customers install these systems and we have them in our own personal vans, which are truly incredible! Update 2025: Our diagrams have been updated to use the latest Victron NG battery systems. This is a super long post where we’ve attempted to take all the knowledge we’ve gathered about a secondary alternator system for a van or RV and organize it into one place! Example Wiring Diagram We worked extensively with Victron Energy and Wakespeed to design a system that will work reliably and safely! However, electrical systems are complicated and we recommend that you either have your system installed by a professional or, if you do it yourself, have it inspected by a professional when it’s completed. Please use the information provided at your own risk. Follow this link to gain access to our library of FREE Camper Van Electrical System Wiring Diagrams. Use the PDF files to print/zoom in. After following the link, open the Vanlife Outfitters 12V Secondary Alternator Wiring Diagram for our example wiring corresponding with this blog post. Why Use a Secondary Alternator? In the last year or so, we’re seeing many more van builders including 400 to 600 amp hours (or more) of battery storage capacity in their rigs. Prior to that, a “large’ system was maybe 300 amp hours. These higher capacity systems are absolutely fantastic for powering your loads for long periods of time while boondocking off grid. Massive battery banks even open up the possibility of using an energy efficient 12-volt air conditioner overnight (check out our comparison of these). However, there are three main problems with these large battery banks. First it’s bloody expensive. But, if you want top-quality batteries with intelligent CAN bus-enabled BMS systems like our Victron Energy Smart Lithium battery example, you’ll just have to bite that bullet. Secondly, it takes up a lot of space. Using fewer, higher density/higher capacity batteries, as we recommend in this post makes this much less problematic. Finally, with that much battery capacity – especially if you’re using a lot of it regularly – it becomes nearly impossible to adequately recharge with solar or DC-DC chargers. As your battery bank grows in size, so does your need for charging. We think adding a powerful secondary alternator is the best solution to this problem. And here’s the thing about a camper van…. you’re going to drive it – that’s sort of the point, right? So, if you can power everything in your van from the engine while driving (or the fuel tank you already have), you are going to have an incredibly capable off-grid rig. Imagine this: fast and reliable battery charging from a secondary alternator, water heating from your engine coolant lines with an Isotemp water heater, and perhaps a Webasoto gasoline or diesel heater sipping tiny bits of fuel from your van’s tank. In fact, in many ways, this system makes having solar panels superfluous which can free up roof space on your van for vent fans, air conditioners and rooftop decks! But, What About Solar? Solar panel charging is a great “bonus” charging source when conditions are “just right” but it’s not reliable like driving since conditions are often not optimal. Obviously, solar charging is only possible during the day and they have to be in the sun and, of course, you also have weather and seasons to contend with. We’ve seen some van builds that have their entire roof covered with solar panels so that they can generate enough power to run a residential-style “split” AC system which is a very complex installation by comparison to a rooftop unit and frankly, may not work correctly after bouncing down the road for thousands of miles. Think about this… they have to be parked in the hot sun during the day in order for this to work at all which is defeating to the goal because it will cause the air conditioner run more which means that there is less energy available to charge the batteries which will be needed to run the air conditioner through the entire night. In this example system we don’t have any solar panels but they could certainly be added in the same manner as we have them on our other example camper van electrical system wiring diagrams. 1. The Nations 280 Amp Secondary Alternator Kit Our kit from Nations Alternator includes the powerful alternator itself which outputs an average of 200 amps and can surge up to 280 at high RPMs! When you compare that to a pair of 30 amp DC-DC chargers that are commonly used in a more “traditional” camper van electrical system, it’s nearly 3.5 times more charging capability. In our testing, we see anywhere between 120-150 amps of charging current at idle and around 200 amps or higher when driving (depending on vehicle and engine RPMs). To put this into practical terms, without considering any solar charging, recharging a 600 amp hour battery bank at 30 amps while driving would take nearly an entire day (20 hours). If you used two Orion DC-DC chargers (which is fairly common), you’d still need to drive for about 10 hours to recharge. With this system, you can charge at an average of 200 amps which would take just over 3 hours of driving which is much more in line with real-world vanlife. You might spend two or three days at a campsite, off-grid, drawing down your battery, and then drive to your next destination. With this system, just a few hours of driving will restore your battery bank. The Nations alternator kit comes with everything you need for the installation including a vehicle-specific mounting bracket, hardware, belts, etc. The installation is not difficult for anyone who has some experience working on cars. It’s also possible to hire your local mechanic to install the secondary alternator – something any qualified mechanic can help you with easily. One important feature of the Nations alternator that wasn’t immediately obvious to us but was explained by our friends at Wakespeed is that it uses something called “avalanche diodes”. Why is that important? Imagine your secondary alternator system is up and running, charging away as you drive and something goes wrong such as the fuse connecting the alternator output to your 12 volt DC bus blowing or someone accidentally disconnecting the battery(s) from the system using the disconnect switch. That situation is referred to as an “uncontrolled disconnect”. When that happens the Wakespeed regulator (more on that below) can detect this and respond quickly with the alternator to dissipate the remaining electricity that now has no place to flow to (often referred to as a “load dump“). However, there is a brief period of time when voltage spikes significantly. If the alternator didn’t use avalanche diodes, this voltage spike would be up to 130 volts (!) going into a 12 volt system, which is as bad as it sounds. However, with the avalanche diodes, the voltage is moderated to about 30 volts, and, get this, apparently, 12 volt systems are designed to handle voltage spikes up to 45 volts. Those diodes just saved your van! Nations Alternator Charging Capabilities Table 2. Wakespeed WS500 Regulator The Wakespeed WS500 regulator is the brains of the operation and interfaces with the alternator and batteries to charge the batteries with the correct voltage, current, and temperature parameters. You can think of the regulator as the device that turns the alternator into an intelligent battery charger rather than just producing current. And, like all battery chargers, it must be configured/programmed to charge the specific batteries you’re using. The Wakespeed regulator is the most advanced regulator of its kind and is regarded by many in the marine/boat world as the very best and most reliable option. It constantly monitors 5 parameters of charging and is highly configurable. Want to learn more about the Wakespeed WS500? We have another post that is a technical deep dive on the Wakespeed including a 1.5 hour video with the founders! 3. High Quality, CAN Bus Enabled Lithium Batteries In a system this powerful, it’s essential that the batteries are up for the job! They must be reliable, robust and one of the brands/types that is officially supported by Wakespeed to work correctly and safely. You can visit the “technical” support tab on the Wakespeed product page to see which battery brands are qualified for safe and effective use. Each of the qualified battery types has a corresponding configuration file available. In order to be considered for qualification, the manufacturer must provide batteries to Wakespeed for testing and engage in “engineer-to-engineer” level conversations with the Wakespeed team. These measures are to ensure that installers can have the highest level of confidence in the functionality and safety of their systems. We also highly recommend batteries that have CAN data connection to their BMS. CAN stands for “controller area network“. It is a highly reliable standard that uses messages to allow many “devices” inside a system to communicate with each other. CAN is used extensively in the automotive industry and has various implementations in the mobile world including RV-C for RVs and NMEA 2000 in the marine world. If you have lithium batteries that have a CAN connection that the Wakespeed can read (or a “language” that it can “translate”), the Wakespeed will use the data available digitally on the CAN bus such as voltage, current, and temperature to very accurately control charging. It can also monitor other messages from the batteries such as disconnect warnings to prevent situations like load dumps. At Vanlife Outfitters, the CAN-enabled batteries we use in secondary alternator camper van electrical systems are Victron Energy Smart batteries (paired with a Lynx Smart BMS and Cerbo GX). Links to example wiring diagrams can be found at the top of this post! In addition to the compatibility, quality, and CAN bus, Victron batteries pack a lot of storage into a small space compared to most of the internal BMS batteries on the market which is, of course, a huge advantage in a camper van or RV! Installing Nations Alternator Installing the alternator onto your vehicle can be one of the most difficult parts of this system if you’re not mechanically inclined and pretty familiar with working cars. That said, if you’re up for the job, one of the things we love about the Nations alternator kits is how complete they are. The kits are unique to each vehicle and engine and come with everything you need to mount the additional alternator – from adapter brackets to belts. Typically you’ll receive two boxes from Nations: one with the alternator itself and the second with the other parts. The kits include very good/detailed instructions so we won’t dive too deep into the vehicle-specific installation process. In our experience, the Promaster kits are the most complicated and the Sprinter kits are the easiest and quickest. The Transit installation sits in the middle of this spectrum. One thing that does trip folks up during the installation is that there is only one “marked” terminal for wiring the charging current output to your system. It’s labeled “B+” and is for the positive charging cable. The negative charging cable can connect to one of the large mounting bolt locations. Below is a photo of these wires connected to the Nations alternator on a Promaster van. We show 4/0 AWG wire used for these runs. If the length of this wire run is less than 15′ you can use the smaller, 2/0 AWG wire instead. In our experience, the Nations 280 amp alternator will output anywhere between 120 and 150 amps at idle and considerably more – 200 to 250 amps when driving. The range you’ll see depends on your vehicle and the engine RPMs. Even the lowest output from the Nations alternator is very substantial compared to most other charging sources that are typically used in a camper van or RV such as solar or shore power. There are dozens of factors that determine how much power you’ll get from a solar panel array (time of day, time of year, how dirty or clean they are, temperature, etc.), but a simple rule of thumb for averaging this range is to predict 5 amps of charging current to a 12 volt battery for every 100 watts of solar. So, even on a perfect sunny day, a roof smashed full of solar panels doesn’t close to the alternator’s output. Shore power is typically one of the most powerful and reliable charging sources. In this example system, the Victron MultiPlus 12/3000/120 inverter/charger can charge up to 120 amps. With these comparisons, you can see that charging at 200 amps or more is really amazing! Victron Smart Lithium Batteries The Victron Smart lithium batteries used in this example system are available in various capacities. We recommend either the 200 amp hour or 330 amp hour versions. Whichever size you pick, you should stick with the same capacity in your battery bank, and, importantly, you’ll need at least 2x batteries (ideally 3x or more) in the system. All lithium batteries have a recommended maximum (continuous) charging current as well as a maximum (continuous) discharge current rating. Below is this information for the Victron Smart lithium batteries used in this example system. Looking at the 200 amp hour version of the battery (circled in red), you can see that the recommended charge current (highlighted in green) is 100 amps which is far less than the alternator is capable of charging. By adding two batteries, you aggregate this capability for a maximum recommended charge current of up to 200 amps. This is cutting it close since the alternator can charge beyond 200 amps – particularly if you have other charging happening at the same time – perhaps something like solar panels. While not ideal, it would work since the Wakespeed is aware of the charging current that’s being generated AND the capabilities/limitations of the batteries so it will respect the limitations and state of the battery. More on this is below in the Wakespeed configuration section of the post. If you use the 330 amp hour version of the Victron Smart lithium batteries, the recommended maximum charging current goes up to 150 amps per battery giving you plenty of extra headroom. On the discharge (load) side of the equation, in most systems, the inverter/charger is the biggest draw since it can power energy-hungry things like microwaves, induction cooktops, 120VAC air conditioners, etc. In the example system, we’re using the popular Victron Energy MultiPlus 12/3000/120 inverter/charger. Taking another look at the specs for the 200 amp hour version of the Victron Smart lithium batteries, you can see the recommended discharge is 200 amps (highlighted in yellow). Meanwhile, the MultiPlus inverter/charger can run loads greater than 3000 watts for long periods of time which is 230-250 amps depending on the load and the battery voltage at the time. So, once again, having 2x or more batteries in parallel gives you the performance you need. The Brains: A Lynx Smart BMS with the Cerbo GX The Victron Smart lithium batteries require an external Battery Management System (BMS). Externalizing the BMS has quite a few advantages that we detail in this other blog post. One major advantage of this particular system is that it enables the Wakespeed regulator to communicate with the BMS (and therefore the batteries) digitally via a CAN bus which makes the system more robust and reliable. It also opens up the possibility for some pretty cool monitoring. More on that later! The external BMS also means that the batteries themselves pack more power into a smaller space compared to batteries with an internal BMS as illustrated in the image below. The BMS we’re using in this system is the Victron Energy Lynx Smart BMS. By the way, any Victron Energy component that has the word “Smart” in its name means that it can be configured, monitored, and controlled via Bluetooth with their free VictronConnect app. In addition, this system uses a Victron Energy Cerbo GX. You can think of the Cerbo GX as a tiny computer with an operating system that is specifically designed for mobile power systems like your van or RV (VenusOS). You connect up all your electrical system components to the Cerbo GX using its wide range of “inputs” and the Cerbo GX allows you to monitor and control them through a simple touchscreen interface. Typically this is facilitated through either the 5″ Touch 50 display or the 7″ Touch 70 display but you can also be done via Bluetooth or even remotely through the Victron Remote Monitoring service called VRM. You can also connect things like water tank sensors, temperature sensors, and more. If you take a close look at our example wiring diagram, you’ll see that the 3x batteries have a short cable coming out of them with circular (M8) connectors. You connect each battery together (daisy chained) with these cables and then that chain of batteries is connected to the Lynx Smart BMS with a longer set of these same M8 cables. Then, the Lynx Smart BMS is connected to the Cerbo GX using VE.Can. CAN stands for “controller area network“. It is a highly reliable standard that uses messages to allow many “devices” inside a system to communicate with each other. CAN is used extensively in the automotive industry and has various implementations in the mobile world including RV-C for RVs and NMEA 2000 in the marine world. Victron’s version is called VE.Can and uses RJ45 (ethernet style) connectors. With all this wired up, the batteries can communicate with the Lynx Smart BMS which can, in turn, communicate with the rest of the power system through the Cerbo GX. OK, back to the BMS. Its job is to listen to the batteries to make sure that they are never damaged. Specifically that they don’t get overcharged (over voltage), too discharged (under voltage), too hot, or too cold. The Lynx Smart BMS is part of the Lynx system from Victron. Many people use the Lynx Distributor in their power systems because it’s a very clever combination of two high-capacity bus bars (DC positive and DC negative) with circuit protection with (Mega fuses) on each of the DC positive terminals that are packaged up in a compact case with a cover. The Lynx Smart BMS bolts right onto one or more Lynx devices. In our example system, we use 1x Lynx Power In and 1x Lynx Distributor as illustrated below. The Lynx Power In is on the left side and is used to connect each of the batteries to put them in parallel. The wires from the batteries to this Lynx Power In should be the same lengths and the positive cable run is protected by a 250 amp terminal/MRBF fuse. Note that you can use a Lynx Distributor for this left-side/battery connection point but the fusing inside the Lynx Distributor would be slightly redundant. In the middle is our Lynx Smart BMS. Inside the Lynx BMS are two important things. One is a current shunt on the DC negative side. This allows the BMS to also serve as a “battery monitor” which is similar in function to the popular BMV-712. The second is an integrated, 500 amp “contactor” which is the equivalent of those large, typically red, main disconnect switches you see in so many power systems. Finally on the right side is the Lynx Distributor that is wired up to all the loads and charging sources. Now that you can visualize how all these components fit together, let’s discuss how they work together. Think of the batteries as the boss. They are one of the most expensive parts of your power system, so it’s important to protect them from distress (over voltage, under voltage, too hot, too cold). The Cerbo GX is the brain. It’s connected to the BMS and most everything else in the system (inverter/charger, solar charge controller, etc.). And, of course, the BMS is the manager (remember, it stands for Battery Management System). The BMS is always listening to the batteries and is responsible for responding if they are distressed. Meanwhile, the Cerbo GX can communicate errors or issues to you and other system components which should respond to the boss. Disconnecting Loads & Chargers to Protect the Batteries Let’s consider how the Lynx Smart BMS can manage some key functions: Disconnect loads from discharging when necessary which is typically when they are overly discharged (low voltage) or too hot or too cold. Stop any charging when necessary – typically when the batteries are overcharged (high voltage) or too hot or too cold. Discharge ControlIn this system, there are what we refer to as “smart” loads that are connected directly to the Cerbo GX which can relay messages from the BMS on behalf of the batteries and control those connected loads digitally. For example, the Victron MultiPlus inverter/charger can stop powering loads when told to by the system. Very smart. Then there are the “dumb loads”. We refer to them as “dumb” because they can’t communicate directly with the Cerbo GX the way the “smart” loads can. In this example system, that would be everything that is wired up to the AD/DC load center on the DC side – things like lights, refrigerator, vent fans, and 12 volt outlets. Another example might be a 12 volt air conditioner that is wired up to a terminal on the “loads and chargers” Lynx Distributor (right side). But, take a look at the illustration of the Lynx system above. These “dumb” loads are electrically “downstream” from the main disconnect switch (contactor) that is built into the Lynx Smart BMS. This opens up two ways to handle load disconnects of “dumb” loads. The simplest approach is to let the BMS turn off (open) its integrated contactor/switch which will electrically disconnect (turn off) everything connected on that right side Lynx Distributor (including charging sources). This is what we show in our example diagram. Obviously, you don’t want this to happen while you’re out there camping in your van so you’ll want to pay attention to any warnings on your touch screen and monitor your battery state of charge. The other way is to make use of the ATD (allow to discharge) relay available on the Lynx Smart BMS to create a sort of “staggered” shutdown where specific, chosen loads, such as your 12 volt load center are disconnected before the entire system shuts down. This might be particularly important in a marine environment where you would want to shut down something like your refrigerator before everything on the boat, including your navigation equipment! The Lynx Smart BMS has a bunch of terminals on the bottom that Victron calls the “multi connector” (see photo below). Our example wiring diagram illustrates how we will connect to many of these. If you wanted to have the type of staggered shutdown we describe above, this is where you could also wire up a Smart BatteryProtect device to the so-called ATD (allow to discharge) relay that can be configured to disconnect the loads that is supplies power to (such as a 12 volt load center/fuse box or a 12 volt air conditioner, etc.) BEFORE the entire system shuts down as a result of the main contactor/switch in the Lynx Smart BMS opening/shutting off. Charging ControlOK, now let’s turn our attention to disabling charging side of the equation in situations when the batteries tell the BMS they don’t want to be charged. Here again, the so-called “smart” chargers that are communicating directly with the Cerbo GX/BMS can receive and respond to the triggers digitally. So, just like the discharge example above, the MultiPlus inverter/charger can be controlled in this way to stop charging. The same is true for a Victron Smart MPPT solar charge controller that has a VE.Direct connection to the Cerbo GX – which is the majority of them. The last charging source in our example system is the dedicated, secondary alternator that is being regulated by the Wakespeed WS500. Similar to the ATD (allow to discharge) relay on the Lynx Smart BMS that’s described above, the Lynx Smart BMS also has an ATC relay (allow to charge) relay. In this system, we will be wiring up the “feature in” (white wire) from the Wakespeed “van harness” such that it receives this ATC (charge disconnect) signal to stop charging when the batteries trigger this state. This is illustrated in the example wiring diagram and detailed more in the Wakespeed wiring harness and configuration section of this post. This ATC circuit is actually a backup to the main communication over the CAN network. Wakespeed WS500 Regulator Now that the batteries and BMS are all sorted out, let’s talk about the Wakespeed WS500 regulator and how it’s used in our example system. We’ll keep this fairly basic, but if you want to take a much deeper dive, you can check out our video with the Wakespeed creators. The Wakespeed regulator turns a fairly basic, but very powerful Nations alternator, into an intelligent, reliable, and smart charging source for your batteries. As we mentioned before, you’ve spent a ton of money on the batteries, so it’s essential that the charging equipment is compatible and will respect the charging profile of the batteries and that’s exactly what the Wakespeed does! Later in this post, we’ll discuss how to configure the Wakespeed to charge the Victron Smart lithium batteries used in this system. CAN Wiring and Wakespeed “Van Harness” Check out our other blog post/video that details every connection on the Wakespeed WS500 van harness. The Wakespeed regulator should be located near the rest of your primary electrical system components such as the batteries, inverter/charger, etc. In a camper van, this is quite often near a rear wheel well in the back of the van. In our example system, we’re using the “white box” version of the Wakespeed regulator that incorporates two RJ45 CAN connections on the bottom of the unit which are the same “ethernet style” jack that you’ll find on the VE.Can port of Victron Cerbo GX. Note: in early 2024, the formerly “white box” version of the Wakespeed regulator starting shipping with a black, plastic case. However, the Victron equipment uses a different wiring configuration than the Wakespeed so you’ll need a special Victron to Wakespeed crossover cable that has a blue connection on one end which plugs into a VE.Can port on the Cerbo GX and a black connection on the other end which plugs into one of the Wakespeed’s CAN ports. This crossover cable comes with a black resisting terminator that should plug into the other CAN port on the Wakespeed and your Cerbo GX will come with a few blue resisting terminators that you’ll put into all the empty VE.Can ports on your Victron equipment (typically one on the Lynx Smart BMS and one on the Cerbo GX). In the example system, we illustrate how to wire up the “van harness” for the Wakespeed regulator. It has a large, main connector that plugs into the big multi-pin connector on the bottom of the Wakespeed. From there the harness has three legs which are detailed in the example wiring diagram and outlined below. If you want to see photos of the real thing on our messy work table, you can check this photo album. Alternator LegThis leg is the longest (about 27′) and is designed to run from the back of your van where the Wakespeed is probably installed, all the way up to the engine area where the Nations alternator will bolted onto the engine. There are two connectors on this leg: one is a black connector with green heat shrink that plugs into the temperature sensor connector coming off the Nations alternator. The other is a grey connector with a blue and a yellow wire. This connector (circled in red in the photo below) should be cut off. Then, the yellow wire that was part of that connector is not used (can be tapped off) and the blue wire that was part of that connector should be butt spliced onto the green wire coming off the Nations alternator. Power System LegThis leg is the shortest since the connections on this leg are typically installed near the Wakespeed which is typically located with the rest of your primary power system components. It has a connector with blue heat shrink that can be connected to an optional battery temperature sensor which we don’t use in our example system. Then there are four unterminated/bare wires: The red wire should be connected to the same terminal on the DC positive bus bar of the Lynx Distributor that the Nations alternator’s DC positive charging output is connected to with an inline, 5 amp fuse. The black wire should be wired up to the DC negative bus bar of the Lynx Distributor. The white wire is called the “feature in” wire and it’s the one we use to send the ATC (allow to charge) signal that was discussed above into the Wakespeed to disable charging if the batteries trigger the BMS to do so. Specifically, it’s wired into terminal #9 on the multi connector of the Lynx BMS and there is a short “jumper” wire between ATC terminal #4 to the relay “common” terminal #8. This is confusing! Please see the example wiring diagram for an illustration and zoom into the detail of this multi connector’s wiring. If you’re using a current shunt (strongly recommended), the purple wire is connected to the small terminal on “alternator” side of the shunt and the grey wire should be connected to the small terminal on the “battery” side of the shunt for current monitoring. Ignition LegFinally, there is a long, brown wire that is designed to be connected to an ignition-controlled circuit. This brown wire turns the Wakespeed on/off (and thus the alternator charging system). If the brown wire “sees” 8.5 volts or higher, it will turn on and enable charging. Typically you would wire this brown wire up to a circuit in your van or RV that is only on (providing voltage) when the ignition switch is enabled or the engine is running. We further recommend that you wire in a toggle switch on the brown wire circuit so that you can turn the Wakespeed/alternator charging off when desired – even when the vehicle/ignition is on. Why This Is Awesome Example #1Running a Mabru 12-volt Rooftop Air Conditioner Overnight with 600 Amp Hours of Battery Capacity Let’s run a scenario where you run a Mabru 12,000 BTU air conditioner in your camper van overnight for 8 hours. Let’s assume it’s cycling on and off about half of the time such that the compressor is only operating for 4 hours during that 8-hour block of time. I’m choosing the Mabru unit in this example because of its extreme energy efficiency. If you take a look at our comparison spreadsheet, you’ll see that the Mabru uses about the same amount of power as the Dometic 2000 RTX while producing nearly twice the cooling capacity! The reason is that Alain Mabru has leveraged his decades of marine cooling experience to engineer an innovative “inverter” system for the compressor. This design provides substantial improvements in energy efficiency, quieter operation and longer longevity than traditional compressors. Scenario #1, it’s freaking hot. So, you’re operating the unit on “high” with medium fan speed. That’s going to draw about 55 amps. Running for those four hours (50% duty cycle overnight) would consume around 220 amp hours from your battery bank. This means that, with no other loads,you have something like 380 remaining amp hours of capacity for other loads throughout your day and you could fully restore the energy consumed by the air conditioner by driving (or idling) for just over one hour! Scenario #2, it’s hot but not freaking hot. In this case, you’re operating the unit in the “eco” mode drawing around 25 amps for the same 4 hours (50% duty cycle overnight). In this scenario, you would consume only around 100 amp hours from your battery bank which means that you have something like 500 remaining amp hours of capacity for other loads throughout your day and you could fully restore the energy consumed by the air conditioner by driving (or idling) for only around a half hour! Configuration With everything wired up, let’s dive into configuring the system! Given the nature of this post, we’re only going to focus on the configuration steps for enabling the secondary alternator and Wakespeed regulator. One awesome feature of this system provided with the Lynx Smart BMS is that the charge profile for the other Victron Energy chargers in our example system (MultiPlus inverter/charger and solar charge controller) is managed intelligently by the Cerbo GX using DVCC. This is possible because all of these devices are “talking” to each other digitally through the Cerbo GX. If you want to learn more about this DVCC magic you can read this section of the Cerbo GX manual. But, If your system has other chargers/devices that don’t have a data connection on them (no VE.Bus, VE.Direct, VE.Can, etc.), such as an Orion DC-DC charger, and therefore cannot be managed by DVCC, you’ll have to configure that device the “old fashioned” way with VictronConnect which is beyond the scope of this post. We also won’t discuss all the setup possibilities of the Cerbo GX – you can check out this other post about that. Instead, we’ll only focus on what’s necessary to make it work with the Wakespeed regulator. However, we’ll be dedicating another post to the Cerbo GX including connecting it to VRM so “stay tuned” for that, or consider signing up for our email newsletter which is available at the bottom of all of our pages. Victron Lynx Smart BMS Configuration with VictronConnectRemember that any Victron product with the word Smart in the name means that you can configure, monitor, and control it via Bluetooth using the VictronConnect app. So, if you haven’t done so already, you’ll want to install VictronConnect. Links to download the app are available for iOS, Android, Windows, or MacOS on the VictronConnect page. Most folks find the app simple to use but you can read through the manual if you need it. To use it, you’ll need Bluetooth enabled on your mobile device or computer so that it can communicate with the various Victron products. Once you open the app, you’ll see a list of all the Victron products that are within Bluetooth range -all with their factory default names. You can easily rename each device to make it unique to your install if you’d like. To configure (or monitor/control) a device simply click on its name from the list in VictronConnect. The first time you connect you’ll be asked to pair with that device. For “older” models, the default pairing PIN is 000000. On “newer” versions the default PIN code will be printed on the sticker on the device. We recommend you change the PIN on all your devices so that other users of VictronConnect don’t mess with your system! Keep in mind that if you find yourself in a place with other camper vans/RVs that have Victron components you might see a bunch of other devices listed in VictronConnect – basically anything that’s within Bluetooth range. By the way, if you don’t have any of this equipment yet but are curious how it all works, you can actually use VictronConnect with “virtual” (demo) devices. In other words, you can go through the settings and screens available in VictronConnect for any Victron Smart product by using the demo library available in VictronConnect. This is a great feature to use when planning a system. Let’s start with the Lynx Smart BMS. Connect to this device in VictronConnect. The first screen you’ll see is the “status” tab that displays the same kind of information as other battery monitors from Victron including the calculated state of charge (SOC) as a percentage and if you scroll down, a bunch of other information about the battery including voltage, current, etc. Below is a screenshot of this screen. Take note of the area circled in red: “allow to charge” and “allow to discharge”. Earlier we discussed these modes that get triggered by the batteries when they are in distress. This is where you can see if these states are triggered. There are several other screens that we won’t detail here but you can read more about them in the manual. Next, click on the “gear icon” in the very top right of the screen to enter the settings. You can use the following screenshot as a guide to these settings however, be sure to set the “Battery bank capacity” and “Number of batteries in parallel” to reflect what is in your particular system. These settings are outlined in red below. In the screenshot, they are set to 600Ah and 2x batteries to match the example system. The rest of the settings we show are fairly universal and typically a good starting point for your system. Also note the “Relay mode” setting that we’ve outlined in green in the screenshot above. This is how the “white wire” (feature in wire) that we wired from from the Wakespeed harness into terminal #9 on the multi connector of the Lynx SmartBMS is interpreted by the BMS. It enables the ATC (allow to charge) relay to disable charging from the Wakespeed/Nations if the battery triggers that state. Note: if you’ve ever configured another Victron Energy battery monitor such as the BMV-712 or SmartShunt you may notice that the settings presented here are different and, in some ways, more simple than you’d see on the other products. That’s because, in this example system, you can literally only use one single type of battery – a Victron Smart lithium battery. The batteries may be different capacities (200 vs. 300Ah, etc.) but they are the same baseline so many of the settings about the battery that you have to change/set in other systems are already known/assumed in this case. Wakespeed WS500 ConfigurationIf you buy your Wakespeed regulator from us as part of a best price secondary alternator product bundle, it will ship pre-configured based on the information we collect when you add the stuff to your cart. However, configuring a Wakespeed WS500 regulator is pretty simple when using the Wakespeed Android app. Note, at the time we’re writing this post, there is a version of the Wakespeed app available for Apple, iOS devices but it can’t connect to the Wakespeed via USB so it can only create and manage configurations – not communicate or send them to the Wakespeed. In addition to the Android app and device, you’ll a USB “on the go” (OTG) cable with one end matching the USB connection on your phone (most Android phones now use USB-C) and the other end having a standard, USB-A female plug such as this one. You’ll also need a short USB-A to USB-B cable. The USB-A end of this cable will pair up with the OTG cable and the other will plug into the USB port on the Wakespeed regulator that is accessed when you remove the lid. Once you have this all connected you can take a look at the following video that does a great job at introducing how to use the Wakespeed app for configuration. Now that you know the basics of how to use Wakespeed app, below is a video of us configuring the Wakespeed regulator for this example system. Note that we’re showing 2x batteries instead of three. This is another place where your particular settings need to be adjusted to match your system’s battery count and storage capacity. In the video, we show the settings you would enable or disable depending on if you have an analog current shunt. More on that is below. Optional Analog Shunt for Monitoring Nations/Wakespeed Current On Cerbo GXIn our example wiring diagram we show an optional Victron Energy analog shunt wired into the Nations alternator’s DC positive charging output wire. We recommend you include this in your system but it is not required. You’ll probably want to locate this shunt close to the rest of your power system components – near the “loads and chargers” Lynx Distributor. The purpose of this shunt is to measure the current flowing from the Nations alternator distinct from the “main” current shunt in this system which is one integrated into the negative bus of the Lynx Smart BMS. In other words, if you add this shunt, you’ll be able to see the current (in amps) and power (in watts) being generated by the Nations alternator when you view the Wakespeed in your system on the Cerbo GX as illustrated below. The left side screenshot is before a shunt was installed in our demo system (outlined in red) and the right side is after (outlined in green). This is pretty cool and allows you to see how much current is coming from the alternator alone without the other charging sources or loads being considered – much like you would be able to see on a solar charge controller. For instance, if your Nations alternator is charging at 150 amps and your solar array is charging at 20 amps and, at the same time, your 12 volt rooftop AC is running and using 55 amps, if you were to look at your primary battery monitor (the Lynx Smart BMS) you’d see an aggregate current readout of something like 155 amps (170 being supplied and 55 being used). Meanwhile, you could take a look at the solar charge controller specifically and see that it was charging at 20 amps alone and look at your Nations/Wakespeed and see it’s charging at 150 amps alone. Note that the Wakespeed can be “powered” in two ways. Normally it would be powered by your van’s power system via the “brown wire” discussed above (ignition trigger wire, on/off wire). Alternatively, when configuring the Wakespeed via USB, the USB cable will supply enough power to turn the unit on. This is very handy for configuring a Wakespeed regulator prior to installation into a system. About “Reading” the Configuration of a Wakespeed Regulator One thing you may notice if you experiment with the Wakespeed Android app enough is that if you edit the settings in the configuration screens and send that configuration to the Wakespeed using the “configure device” and then use the “copy” feature that reads the config file from that device back into the configuration screens of the app, most of the settings you’ll see in the configuration window will NOT match what you think you had set up. The same thing can happen if you connect up to any pre-configured Wakespeed regulator using the Android app expecting to see the configuration options “match” the options in the user interface. Why is this? When you’re configuring a Wakespeed using the app interface, what is happening “behind the scenes” is that your selections are getting “translated” into a “lower level” configuration file that looks something like the screenshot. In other words, the app is allowing you to create a config file in a user-friendly way but, at a deeper level, many of the choices you’re making are getting converted into the values and formatting the Wakespeed actually needs to be programmed. When you “copy” a current configuration of a Wakespeed, you’re retrieving this ‘lower level” file that, when opened in the app, doesn’t line up with the selections available in the user interface. Thus, when you do a “copy” you’re actually creating a brand new configuration file. Firmware If you’re experiencing problems with your system be sure that the firmware is up to date on all the devices. On the Wakespeed you do this from the Wakespeed app. Tap on the “home icon” at the top left and then select “device” and finally “firmware update”. You need version 2.5.0 or higher for the system to work correctly with the Cerbo GX. On the Cerbo GX you’ll need to have version 2.90 or higher of the Venus OS. You can check this by opening the menu, navigating to “settings” then “firmware” then “online updates” and then press on the “check and update” button. On the Lynx Smart BMS you’ll open that device up in VictronConnect then press on the “three dot menu” in the top right part of the interface and choose “product info”. Find the “firmware” link and press update. Flashing Orange Light When the Wakespeed is up and running and configured correctly in this system you should see its LED light flashing a “reddish orange” color. This has alarmed some of our customers who think that the flashing LED indicated some kind of problem but, in fact, it means that the Wakespeed is being controlled by an external BMS which is exactly what you want in this example system. Common Errors/Conditions with the Wakespeed WS500 Regulator Error 51If you’ve wired your Victron Lynx Smart BMS remote terminals to a toggle switch in order to be able to use the built-in “contactor” to turn the system on/off as you might with a typical main battery switch (those big red switches) you will get an error 51 thrown by the Wakespeed regulator when you use the toggle switch to turn off the system. The reason is actually good news. When you trigger the remote off function, the Lynx Smart BMS is able to send a message over the CAN bus to the Wakespeed regulator that puts it into this fault code and disables charging before it actually turns off the system (opens its internal contactor). This allows the Wakespeed to stop the Nations alternator from charging before the batteries are disconnected preventing a “load dump” which can be harmful to the alternator and your system. Think of it as a helpful “head up” prior to the disconnect. If you see an error 51 in this context, this would be the most likely reason. The only way we’ve found to reset this error is to make sure the Wakespeed is switched off (ignition/brown wire) and then the RJ45 CAN connection out of the Wakespeed regulator for a few seconds and then plug it back in. Error 91This error indicates that the Wakespeed has lost its connection with the Lynx Smart BMS and it will go into a “get home mode”. As soon as the communication is restored it will revert to the charging goals set by the BMS. Error 92The ATC (allow to charge) state has been triggered by the batteries and the Lynx Smart BMS has communicated this to the Wakespeed and, as a result, the Wakespeed has been turned off to disable charging. Error 44The WS500 is capable of providing a broad range of error and advisory codes, which are displayed by the LED that’s exposed via the jewel on the lid of the regulator. Error codes are preceded by two red “bursts” of flashes, followed by a two-digit display of flashes. In the case of an error code 44 (indicated by four flashes, a space, and four more flashes), the regulator has monitored an excessive voltage difference of greater than 2.5VDC between the regulator’s positive voltage sense (red w/yellow tracer) wire and positive power (solid red) wires. This may indicate an excessive voltage drop between the two wires, or the existence of a damaged fuse in one or the other wire. A full list of error/advisory codes is available in the WS500 Communications and Programming Guide, available on our website. Powering Up and Testing Power up the DC system by turning “on” the switch wired into the Lynx Smart BMS “remote” terminals thereby closing the contactor inside the BMS. Confirm that the small loads like the Cerbo GX are powering up. Turn on the MultiPlus inverter/charger with the power switch on the unit itself. When the Cerbo GX running, try controlling the MultiPlus from the Touch 50/Touch 70 screen (switching modes from off/charger only/on, etc.). If you have issues with this, make sure the VE.Bus connection between the MultiPlus and the Cerbo GX is correct (RJ45 UTP network cable) and you’re using a manufactured (not hand-crimped) cable. Confirm that you are getting 120 volt AC to your load center (from the AC output 1 terminals on the MultiPlus). Confirm that you are getting 12 volt DC to your load center. Configure the various Victron Smart devices using VictronConnect via Bluetooth. Configure your Cerbo GX and connect to the free Victron Energy VRM cloud service. Test the secondary alternator by starting the vehicle and then turning on any switch that may be wired into the “brown, ignition trigger wire” of the Wakespeed WS500 harness. Once the vehicle is running and the Wakespeed is powered up, you should see the LED light on the Wakespeed flash an orange/amber color indicating that it’s being controlled by a BMS. In this case, that’s the Victron Lynx Smart BMS. Confirm that you’re getting a charge current from the alternator by looking at the battery monitor (shunt inside the Lynx Smart BMS) information on the Touch 50/Touch 70 connected to your Cerbo GX. Note, if the batteries are close to full this will be a small amount of current necessary for an absorption charge. You can discharge the batteries using a heavy load such as a heat gun or similar high-wattage appliance in order to see the alternator’s output during a bulk charge. Test your shore power input to make sure that the MultiPlus syncs to the incoming 120 volt AC power and that the internal transfer switch transfers the loads to the shore/utility power. You’ll hear an audible click. Additional Resources Wakespeed WS500 Technical Deep Dive Video Wakespeed WS500 Regulator Manual Wakespeed Video Resources
Learn more
How To Insulate Your Camper Van
wI’ve probably put more thought into insulating my camper vans than is considered sane or healthy. I can’t exactly say why I choose to obsess over this more than almost any other part of the van build, but that’s another conversation between myself and my therapist. You might be asking: “Who are you and what makes your system so great?” Well I don’t consider myself an insulation expert and I don’t know if that title exists in vanlife. But I’ll tell you a little about my experience. Since getting into vanlife in 2017, I’ve built or been involved in the build of over 15 camper vans and I’ve seen countless other vans being built. I’ve also done dozens of hours of research, reading and YouTube rabbit-holing. I’ve personally seen wool, thinsulate, reflectix, EPS foam board, spray foam, rock wool, fiberglass, denim and every other type of insulation and insulation method or system in the universe. All of that research and observation has led me to the creation of a system that I use in my vans and recommend to any of my friends, family and vanlifers who are building their van. In this blog post I’m going to keep it as simple as possible. I won’t be going deep into the science and analytics behind my system because that blog post is far too long and boring. If you have any questions or want a more technical discussion please feel free to reach out to me via e-mail or attend my Camper Van Insulation Analytics Ted Talk at MIT this Summer (just kidding). What You’ll Need Of course, the specific quantities will depend on your van. Materials: ¾” EPS Foam Board ¾” Plywood ½” Plywood Marine Sealant Sound Deadener (80 Mil Preferred – Noico, Killmat, Etc.) Thinsulate SM600L (Automotive) 3M 90 Spray Adhesive Low-E Reflective Foam with Low-E Tape Rivnuts Wood Screws (1″ or dependent on your plywood choices) Tools: Heavy Duty Scissors Heavy Duty Caulking Gun Rivnut Installer Tool (Pneumatic/Hydraulic recommended) Drill Table Saw or Circular Saw Phase One: Sound Deadener (Noico or Killmat) I start by applying a sound deadener product like Killmat or Noico that volume to the sheet metal of your van which, in turn, reduces vibration that adds a lot of noise to an empty van. Some people choose to line their entire van with sound deadeners which in my opinion is an incredible waste of money and weight. In my experience, you only really need to cover 25% of each panel and I highly recommend you also cover the floor and wheel wells of the van completely as these especially are a high source of noise. Sound deadener is easy to use, just cut to size, peel the back, stick in on the sheetmetal and press or roll in on. Phase Two: Insulation (Thinsulate SM600L) I have an entire blog post on why I like Thinsulate over wool. It’s a superior product to everything else on the market. I apply Thinsulate to the skin of the van over sound deadener with 3M 90 spray adhesive (spray the wall and the white side of the Thinsulate, wait 10 seconds, then stick the white side of the Thinsulate to the wall. I apply Thinsulate to every inch of the visible walls of the van. I also tuck Thinsulate into the door, ribs and crevices of the van (everywhere you can). I also take down the headliner over the cab and stuff Thinsulate and Low-E (see below) in there as well. The only place I don’t install Thinsulate is on the floor (more on that later). Once the Thinsulate is completed, I prewire the van and run all the branch wires to where the electrical system will be located. Phase Three: Floor (EPS Foam Board, Silicone, Plywood) Once you’ve installed the sound deadening and Thinsulate, this is a good time to think about installing your subfloor. The process of installing the subfloor is a little different from the rest of the van. I cut three-quarter-inch plywood into three inch wide furring strips and attach them to the floor using marine sealant. I install the furring strips in a grid pattern with each strip about sixteen inches apart vertically and sixteen inches horizontally. Your floor should look like a giant tic-tac-toe board. I then cut three-quarter-inch thick EPS foam board (the kind with the foil on one side) into squares to fit the empty spaces between the furring strips. I place the EPS foam squares with the foil side facing up and tape them in using foil tape. At this point your floor should look like it’s covered in aluminum foil. The last step is to template out your floor onto three-quarter-inch plywood and screw your subfloor into your furring strips with wood screws. Phase Four: Furring Strips (Plywood) In this phase, I install half-inch furring strips (half-inch plywood cut into three-inch wide strips) on all the ribs of the van using Rivnuts (or Plusnuts) but I don’t fully tighten them yet since I will eventually take them down to re-install to hold the Low-E (Phase Four) in place. Furring strips are important for a couple reasons. The first reason is that it gives you something to screw your walls and ceiling into. When you screw directly into the ribs in the van it creates metal on metal squeaking, it creates many more holes in your metal than is necessary (potential for rust) and most importantly it allows heat to be transferred (I will save you a boring lesson on the dynamics of heat transfer) from the metal of the van into the screws and then into your van. Imagine each screw head as a tiny heater giving off heat in your van, hundreds of those tiny heaters give off a lot of heat. The second reason furring strips are important is that they give you the opportunity to create air gaps. Air gaps provide an additional thermal break between your insulation and your interior wall. I will also save you a boring lesson on thermal breaks, but just know that they’re good. I also have a theory that having an air gap creates additional sound insulation, but this is just a theory. The only drawbacks I see to using furring strips would be additional weight, additional cost and losing a half-inch of height and an inch of interior width in your van. Phase Five: Radiant Barrier (Low-E) Low-E is similar to Reflectix, but it is superior in quality. Low-E is a 7/32″ closed cell foam that is backed on both sides with pure aluminum foil (not “metallic looking” plastic like Reflectix). It acts as a reflective radiant barrier to deflect heat from away from the living space. It also acts as a very good vapor barrier and reduces condensation if installed properly. Many automotive window shade manufacturers use Low-E inside their window shades to reduce the amount of radiant heat that is allowed into the vehicle. The Low-E comes in six-foot wide rolls. This means that one piece can cover the entire ceiling, another single piece can cover the passenger wall, and another single piece can cover the driver side wall. I measure and cut a single piece for each wall and another for the ceiling. I also cut pieces for the doors and the headliner over the cab. If you have any Low-E left over and you’re crafty then you can make window shades. I take the Low-E piece I cut for the ceiling and put it up on the ceiling with magnets to hold it in place. I then mark out where all the rivnuts for the furring strips are. I reattach the firring strips to permanently hold the Low-E in place. I repeat the process with the driver’s and passenger side walls. I then tape the seams where the Low-E for the walls and ceiling meet with foil tape. (Don’t forget to make small holes to pull your wires through and make sure the holes are as tight as possible to the wire). You should have a seamless Low-E “shell” inside the van when this stage is completed. There will be an air gap between the Thinsulate and Low-E of about 1/2″+/- depending on the make/model of your van (this is your first air gap). This photo shows the Low-E on the walls with furring strips locking it in place. There is an air gap between the Thinsulate and the back of the Low-E and there will be another air gap between the front of the Low-E and back of the plywood wall. The next step in the photo would be to take the furring strips off the ceiling and install the Low-E and put back the furring strips on top and then tape the seam where the wall and ceiling are joined. (The Low-E on the wall in the photo is cut because there is a window there). Phase Six: Walls & Ceiling (Plywood) Lastly, I install my plywood walls and ceiling by screwing them into the furring strips with wood screws. The space the furring strips creates between your Low-E and plywood walls is your second air gap. Theoretically, any heat that isn’t reflected back by the Low-E would have less of a chance of transferring to your walls. Vanlife Outfitters has been supporting DIY camper van builders since 2016. We have a large collection of blog posts, videos, tips, resources, information and products to help you on your journey into vanlife. If you got any useful information from our site please let us know and if you’re in the market for products to build out a van please consider supporting our store!
Learn more
Sizing Your Electrical System & Load Calculations
One question we are asked all the time is “how many batteries do I need for my van’s power system”? Or, how many solar panels do I need to run my AC?” This is a very simple question with a stupidly complex answer. I mean, look at how long this blog post is. Ugh. First, solar panels are a charging source – typically one of many. Don’t conflate a “solar system” with what you actually need, which is a complete power system. We’ll dive into that more later but, for now, let’s start by rephrasing the question to “how much battery capacity do I need to be off-grid in my van”. Water Analogy One simple way to think about this is to use a slightly more familiar analogy: how much water do you need in your van? Which, of course, depends on how much water you’ll be using. Do you shower every day? Do you never shower (don’t be like that)? Are we talking about a long luxurious shower or a quick rinse? How much water do you drink? How often do you do dishes? You get the idea. Everyone’s answer is going to be different. So, let’s start by thinking about batteries as tanks of water – each containing a specific amount of water measured in gallons since many of our readers/customers are ‘Mericans. In batteries, we’re measuring stored energy – just like the stored water in a tank but, instead of gallons, the metric is amp hours or watt-hours. In water systems, the amount of water you use depends on the flow of a tap/valve. If you turn the faucet on full blast your tank will empty much quicker than if you have it running at a trickle. In electricity, your faucets are what we call “loads”. Some loads, such as LED lights or charging a phone, are small (a trickle of water). Other loads are large (a firehose of water) such as an air conditioner or an induction cooktop. In power systems, the flow rate is called current (amps) and the pressure is called voltage (volts). So, just as you have a finite and measurable amount of gallons in your water tanks, your batteries also have a finite and measurable amount of amp hours in them. How to Monitor Consumption Every electrical system should have a capable battery monitoring system such as the Victron Energy BMV-712 or SmartShunt. It gets wired into your electrical system like a water meter is installed onto your house. As you use power it will track your usage against how many amp hours you had to start with when the battery bank (tank) was full. With this information, it can tell you, with reasonable accuracy, how much power you have left in your batteries (and other stuff). Load CalculationSucks, But Worth It So, how many amp hours do you need in your tank? It’s going to take some math kids! You need to do what’s called a load calculation. Fair warning, this is going to take an hour or two and isn’t particularly fun (it sucks) but it’s worth the effort. To get you started, we have a free example load calculation Google Sheet. If you click on the link it will open up and prompt you to make a copy. Note, that you’ll need a Google/Gmail account to use this Google Sheet. Once you have your copy you can experiment with it and edit the values as you see fit. There are three example sheets that you can use as launching pads for your system: The first sheet/tab (named “Ex. 1: 600 Watts Solar, Moderate Driving, 12v AC”) is a larger system – it has pretty typical loads but also adds a Mabru 12 volt air conditioner that is run for a few hours every day. It has three, standard charging methods (much more on that later). In a system like this, you’d probably want to use external BMS batteries to take advantage of the significant space savings they provide and this best price product bundle would be a good starting point. The second sheet/tab (named “Ex. 2: 400 Watts Solar, Moderate Driving, No AC “) is a more modest system that is similar in loads but has a smaller solar array and omits the air conditioner making the total consumption much lower. It’s a good candidate for 2-3x internal BMS batteries and this best price product bundle. The third sheet/tab (named “Ex. 3: No Solar, Driving w/ 2nd Alternator, 12v AC”) is the most powerful system that uses a dedicated secondary alternator for rapid charging and doesn’t have/need any solar panels at all. It has all the same loads but assumes the AC unit will run all night. In this van, you can imagine the owner having a nice roof deck or other ways of using that roof space. We have a best price product bundle for secondary alternator power systems as well! But, hang on. Resist the temptation to dive into those spreadsheets right now and start tweaking the numbers. We suggest you read on a bit further to know what they mean first. The first step is to identify all your loads – everything that is going to be powered by your electrical system: lights, Maxxfan, refrigerator, microwave, blender, coffee maker, chargers, Christmas lights, flame throwers, all of it. As you do this, keep two lists: one for things that run off 12 volt DC – directly off the battery. And another for things that require household power – 120 volt AC – things that have a plug that you’re used to using in your house – a normal outlet. To power 120 volt AC loads, you need something called an inverter. It is wired to your batteries and converts (inverts) the 12 volt DC (direct current) to 120 volt AC (alternating current). OK, take a quick peep at your copy of the load center worksheet. In all of the examples, you can see that there are four sections/tables. Go ahead and list out your DC loads in the top table and the AC loads in the next table below – into column A. Don’t worry about the numbers yet but feel free to add “rows” if needed to accommodate your list of loads. Now that they’re all listed you have to find out the power consumption of each. Going back to our water analogy – is this thing a drip or a firehouse? We want to put those numbers into this “amp draw” column (column B). DC Loads You can start with the DC stuff since it’s typically easier because often the sticker or info you find will already be listed in amps. That’s handy and will save you some math. AC Loads Now let’s do some of the AC loads. Quite often the power consumption of AC devices are listed in watts. To convert that into amps, we’ll use the following formula. I know, math. I agree. It’s simple tho. The formula is:Amps = Watts / Volts In this case the volts in your battery voltage. We talk about 12 volt batteries but that’s honestly a pretty deeply discharged battery. The “nominal” voltage on a battery you’re likely to use is 12.8. So, here’s an example. An induction cooktop says it uses 1800 watts. However, that’s the maximum draw on super-duper-high. Typical consumption is closer to 1200 watts. Even so, it’s typically best to plan for the “worst case scenario” in these load calculations. So, our math to convert this into amps is 1800 divided by 12.8 which is 140 amps. Yipes! Compare that to our LED puck lights at 1.5 amps. Those are the drips and the cooktop is a true firehose. So, go ahead and list out all your AC load values into column B of that middle table. Time Now we can get into the last variable – time. Going back to our water analogy, we know that long showers consume more water than short ones – even when the flow rate is the same. Of course, it’s the same with electricity. Go through each of your DC and AC loads and add something into the “Estimated Hours Used Per Day” column (column C) for each. We can start with that cooktop which was a monster firehouse of consumption. However, if you only use it for 5 minutes it makes a big difference. This is why the answer to the original question is not universal. Some people cook a lot, some people don’t cook at all. So each electrical system and battery bank needs to be customized to your particular needs. Everything should be entered in hours. So, in the case of the cooktop, we need to divide 5 minutes by 60 to arrive at .08 of one hour. Let’s do the refrigerator next. This is tricky because there are a ton of factors that determine how often the refrigerator is going to be running. How hot is it in the van, how often are you opening the door, how much stuff is in there, etc? In this example, we’re estimating for an Isotherm Cruise 130. According to the manufacturer, the “average” draw of this model is 34 amps a day. If we divide that by 24 it comes out to be 1.5 amps per hour on average. So, that’s what we’ll use. It will be running all the time so we’ll use 24 in the hour column. Now check this out. That firehose of electrons, the cooktop only consumes a bit over 12 amp hours per day in this estimate. Meanwhile, the fridge, which is a drip by comparison (1.5 amps), is predicted to use nearly three times as much energy at 36 amp hours. This illustrates how important run time is. And, getting back to the original question: how many hours can I run my AC off my batteries? Let’s reverse the question for a minute like you’ve done with the other loads. How long do you want to run that AC every day and what is the flow rate or energy utilization of the AC? And, well, it gets even more complicated. What KIND of AC unit are you going to have in your van? To keep this complex answer as simple as possible, we’ll narrow this down to two choices: a traditional, RV, style, 120 volt AC rooftop unit (think Coleman, Dometic, etc.) or a newer, 12 volt DC rooftop unit (think Mabru, Dometic RTX 2000, etc.). If you dive into the specs of these options (check out our comparison sheet), the 120 volt AC models use right around TWICE the amount of power as a 12 volt model. But, the 12 volt options are also somewhere around TWICE the cost. Despite that, when you consider the cost of batteries, they tend to be a better value. So, let’s consider a Mabru, 12,000 BTU 12 volt unit. It uses anywhere between 22 and 55 amps depending on the cooling mode and fan speed. Let’s plan for a hot day where we will be running it on high overnight. But, our van is insulated, we have window coverings and we’ve set the thermostat to a reasonable temp. So, it won’t be running constantly all night. How often will it cycle on/off? Of course, it’s impossible to know for sure but let’s say the compressor is running about half the time. So, we’ll put 55 amps into the amp draw and 4 hours into the time column (half an eight-hour night). That totals 220 amp hours in a single day. There’s one version of the answer about air conditioners… But there is more! Consumption Totals Once you put in the time values for all your loads you’re halfway done. Ha ha, not really – you’re a bit more than halfway done. Told you this was a lot of work! At this point you know how much power your system is going to use – you can see in the bottom table (totals table) in the sheet. Look for the row called “Total Estimated Daily Consumption (Amp Hours)”. You can use this number to estimate how many batteries you need. In the first example sheet (named “Ex. 1: 600 Watts Solar, Moderate Driving, 12v AC “) the total consumption (before any of your customizations) was 358 amp hours per day. Recharging However, before you rush out and buy 400 amp hours of battery, let’s talk about recharging. How do you refill your empty tank? The next exercise is to model your charging sources. In a van, it’s very common to have 3x of these: solar, alternator charging of some kind when driving and shore power which is when you’re connected to the grid at a house or campground and can use that utility power to charge your batteries. Therefore, we’ve provided a row for each of these methods. We recommend that your van have all three. So, let’s start with solar and make it as simple as possible by ignoring all the real-world complexity of solar systems that affect their performance such as time of day, time of year, how cloudy it is, angles, how dirty or clean or panels are, and so on. We’ll use a simple rule of thumb for solar charging: for every 100 watts of panels you have on your roof, we’ll assume 5 amps of charging output to the batteries. So, if you have 400 watts of solar, you can enter 20 amps for that charging source. Of course, you’re welcome to do a more nuanced calculation here if you happen to have a very good idea of the places and light conditions you’ll be traveling in and knowledge of the panels you’ll be using. Just like loads, the amount of time you’re charging makes a huge difference! In this example, we’ll assume we’re parked in the full sun while we’re off at the beach all day and enter 8 hours which will produce an estimated 160 amp hours of power to charge the battery bank. The second way most people charge is with their vehicle’s alternator. We have a bunch of example power systems on our blog that you can take a look at. The most common options are either using one or more DC-DC chargers. The Victron Energy Orion DC-DC chargers can charge at up to 30 amps and most of our customers use two of them in parallel for 60 amps of charging. Blog update 2025: one or two Victron Orion XS 50 DC-DC converters is a great choice. Typically you don’t want to exceed 60 amps or 45% of your vehicle alternator’s rating. This is a substantial charge while not overtaxing your vehicle alternator. In fact, even if you use a single DC charger, that’s typically more charging current than having 400 watts of solar! In our example sheet, we’ll use two of these (60 amps) and expect to drive for 3 hours each day. Finally, so-called shore power which is whenever you can plug your rig into utility power. Often this is at a house or a campground. Remember that inverter we talked about that converts 12 volt DC power from your battery into 120 volt AC power for household-style loads? Often these things have a charger component that does the opposite – takes the utility power and converts it into some flavor of 12 volt DC power to charge your batteries. These are called inverter/chargers and we definitely recommend your inverter has this feature. Our most popular inverter/charger is the Victron Energy MultiPlus 12/3000/120 which can recharge your batteries at up to 120 amps! Notice how the charging capacity ramps up with each of these in this hypothetical example with solar being the sort of drip and shore power being more like the firehose. However, most of our customers prefer to stay off grid (boondock). For this reason, our example sheets have 120 in the amps column but zero into the time column. But, if your adventures lead to places with hookups, shore power can be a tremendously powerful charging source – even if it’s only once in a while. A Delicate Balance Now that we know about our loads (water going out) and our charging sources (how we refill), we can see how they balance out! In our first example sheet (again, before any changes were made), our expected daily utilization is about 62 amp hours less than our expected daily charging. That’s pretty good. If you see the opposite, where you’re using more power than you’re recharging, that is where your batteries come in. You want to size the capacity of your battery bank so that it is larger then your daily loads. If you expect your charging sources to be more variable (some sunny days, some days with less driving) you may want to have a larger battery bank to compensate and allow for these flutuations. Typically in a camper van power system a battery bank is comprised of two or more 12 volt batteries that are identical wired up in parallel. This method of creating the “bank” keeps the voltages the same but adds up the amp hour storage capacity. In the example described in the first sheet, we might use 2x or 3x of the Victron Smart 200 amp hour batteries to create a nominal 12 volt battery bank with 400 or 600 amp hour of storage capacity. Another reason to use multiple batteries is to ensure that your “bank” is capable of running your heaviest loads. Lithium batteries have a “maximum continuous discharge” rating that is often in the 50 to 100 amps range. Combining batteries together into a bank allows you combine this specification as well. So, if you have 3x batteries, each capable of 100 amps of continuous discharge, the combined bank of batteries would enable a maximum continuous discharge of 300 amps. Consider a 3000 watt inverter – if you max that out, you’d be looking at around 235 amps. That means the same batteries combined into a bank of 2x batteries wouldn’t provide enough juice to run that continously but 3x batteries would. While lithium batteries are a lot more resiliant to being discharged deeply compared to older lead acid/AGM batteries, most manufacturers recommend keeping your batteries above 20% state of charge to ensure the longest lifespan. So, if you have a battery that’s rated for 100 amp hours, you should consider only using 80 amp hours in your calculations. Going back to the water analogy, you could simply add a bigger water tank so that you can go longer without refilling or, in this case, recharging. But, the more balanced your consumption is with your utilization, the less you’ll have to worry about power. One of the key things to take away is that simply adding batteries for additional capacity isn’t a sustainable option without recharging sources. Now that you have a reasonable idea of what a day in the life of your power looks like, the last big question is how you’ll be using the rig over time. Are most days the same? Do you expect to drive a lot on certain days for additional alternator charging? Perhaps you expect to be at a campground or back at your stationary house every few days so you can use shore power to recharge your rig every night? There are so many unique scenarios. With the information you know from your load calculation, you can project how these scenarios would play out. Ultimately, these scenarios give you the insight you need to size your battery bank. Obviously, it’s best to have a little margin so that if your projections are wrong you have some extra juice. Another tip is to consider leaving space for one more of your chosen batteries. If you do find yourself with an energy deficit regularly, wiring in another battery is really simple if you have the space. Dedicated Secondary Alternators for High Power Recharging As battery banks get larger and larger an increasingly popular option is to add a secondary, dedicated charging alternator to your rig. So, instead of using DC-DC chargers that top out at 60 amps of charging to protect the vehicle alternator, you bolt on another high-current alternator from a company like Nations. These charge at anywhere between 120 to 200+ amps depending on your vehicle and the RPMs of the engine which means they can recharge large battery banks in a few hours. You can see the effect of this in the third sheet in our example load calculations (named “Ex. 3: No Solar, Driving w/ 2nd Alternator, 12v AC”). Next Steps If you made it this far and your head has not exploded, you rock and you’re a good candidate for installing your own DIY electrical system. We have a ton more information on our blog – many of which were linked to from this post. If you stopped reading because your head was about to explode, we have real people to talk to. Consider reaching out!
Learn more
Tech Deep Dive - Wakespeed WS500 Regulator
This post includes an extensive deep dive video with Wakespeed founders, Al Thomason and Rick Jones facilitated by Zach from Vanlife Outfitters and Jesse from Valley Hi vans. In addition, we’ve summarized some of the common questions we get about this amazing product in this post. We feature the Wakespeed in our secondary alternator example wiring diagram and best price product bundle. How is the Wakespeed WS500 regulator superior to something like a Balmar regulator? What really sets the Wakespeed apart is its ability to use voltage, current, and temperature signals to regulate charging rather than only voltage compared to something like a Balmar regulator. Additionally, the Wakespeed can monitor these signals digitally when used with CAN-connected batteries such as Lithonics and Victron Smart batteries. There are many other unique features but this foundational difference is key! What is a CAN bus and how does it work in a system with a secondary alternator with a Wakespeed regulator? CAN stands for “controller area network“. It is a highly reliable standard that uses messages to allow many “devices” inside a system to communicate with each other. CAN is used extensively in the automotive industry and has various implementations in the mobile world including RV-C for RVs and NMEA 2000 in the marine world. If you have lithium batteries that have a CAN connection that the Wakespeed can read (or a “language” that it can “translate”), the Wakespeed will use the data available digitally on the CAN bus such as voltage, current, and temperature to very accurately control charging. It can also monitor other messages from the batteries such as disconnect warnings to prevent situations like load dumps. At Vanlife Outfitters, the CAN-enabled batteries we use in secondary alternator camper van electrical systems are Blog update 2025: Victron NG batteries (paired with a BMS and Cerbo GX). There are two versions of the Wakespeed WS500 regulator. What is the difference between the “white box” and “black box” versions of the regulator? The white box Wakespeed WS500 has RJ45 CAN bus connection ports and the black box does not. In both cases, the wiring harness used with the Wakespeed has a standard CAN connection. So, if you have the white box, you have two options for CAN connectivity whereas the black box simplifies this to only one. Which version you use is typically determined by which type of CAN-connected battery you have in your system. If you’re using Lithonics batteries, you would normally use the black box version since you don’t need the RJ45 connections. In a Victron system with a Lynx Smart BMS and a Cerbo GX, you’d normally use the white box since the Victron equipment communicates CAN through the Victron VE.Can standard which uses RJ45 connections. Note: in early 2024, the formerly “white box” version of the Wakespeed regulator starting shipping with a black, plastic case. Blog update 2025: all of our secondary alternator kits include the latest generation WS500 Pro regulator. When using Victron Smart NG batteries with the Wakespeed, you’ll need the “Wakespeed to Victron” crossover cable to adapt the pin configuration that Wakespeed uses on their RJ45 connections to those used by Victron Energy on theirs. In Victron systems, you’ll want to be sure the Wakespeed is running firmware version 2.5.0 (or higher) and the Cerbo GX has Venus OS 2.90 (or higher). The Wakespeed guide for Victron systems is a great resource to check out. When using Lithonics batteries with the “black box” version of the Wakespeed, you’ll need a few adapter cables. The image above shows a 2x battery set up with the Wakespeed “CAN Bus Y Adapter cable” and a Litihonics “Wakespeed/Iongauge Integration Harness”. What brands of lithium batteries have been qualified to work correctly (and safely) with the Wakespeed WS500 regulator and why are only certain brands supported? You can visit the “technical” tab on the Wakespeed product page to see which battery brands are qualified for safe and effective use. Each of the qualified battery types has a corresponding configuration file available. In order to be considered for qualification, the manufactuer must provide batteries to Wakespeed for testing and engage in “engineer-to-engineer” level conversations with the Wakespeed team. These measures are to ensure that installers can have the highest level of confidence in the functionality and safety of their systems. How do you use the Wakespeed WS500 regulator with “legacy” batteries that don’t have a CAN bus connection including “drop-in replacement” batteries with internal BMS like Battleborn lithium batteries? Unlike CAN-connected batteries where the voltage, temperature, and current are available digitally, systems that use internal BMS batteries without CAN connections like Battleborn need an analog shunt for current monitoring and a battery temperature sensor so that these signals, along with voltage can be used by the regulator for optimal charging. Currently, Battleborn is the only brand of this type of battery that is qualified by Wakespeed. In addition to using a qualified battery, you should be sure to design your system with at least 3x batteries so that if the BMS in one or more of the batteries disconnects from charging there is at least one or two remaining online to absorb the charging current so there isn’t a “load dump” situation. What is the difference between the standard wiring harness and the “van harness”? The Wakespeed WS500 regulator has various wiring harnesses that plug into the large port on the bottom of the regulator. These variations are designed to accommodate different types of installations. The most commonly used harnesses are described below. The standard harness is most often used in marine environments where the regulator is placed near the engine. It includes all of the connections/wires detailed in the quick start guide. The so-called, van harness is designed for, you guessed it, vans! It assumes that the Wakespeed will be placed near the rest of the van’s electrical system components in the rear area of the van so it has a long (approximately 27′) leg that runs up to the alternator location and another long (approximately 17′) leg that runs to the vehicle’s ignition switch circuit (brown wire). Check out our other blog post/video that details every connection on the Wakespeed WS500 van harness. FREE Camper Van Power System Resources & Wiring Diagrams If you’re confused about your DIY camper van electrical or solar system, you’ve come to the right place. We have tons of resources including blog posts, videos and detailed example wiring diagrams (see below), Our “choosing a system” page offers some additional advice and includes an example load calculation that you can use. Please consider purchasing your power system equipment from our store. Our bundles offer great pricing (yeah, better than Amazon), free shipping and you’ll have access to expert support and you’ll be supporting our ability to create more content! Finally, there are a few things that we don’t sell in our store (yet!) that you might need so we keep a list of these products in this Google Sheet of recommended camper van products.
Learn more
Professionally Altitude Adjusted Webasto Air Top 2000 Heaters
We’re really excited to be launching professionally pre-adjusted Webasto heaters for customers living at higher altitudes in cooperation with our partners at VMACS and Red Point Conversions. The first product in this line up is a pre-adjusted, gasoline Air Top 2000 STC. Back Story The Air Top 2000 STC heaters (available in both gasoline and diesel versions) are extremely popular for camper vans since they are very small, very energy efficient (both fuel and electricity) and capable of heating the small cabin spaces of camper vans. However, if their standard, factory state, they are only rated for “continual operation” at altitudes up to 4,900 feet. Meanwhile, many of our customers are living and traveling at higher altitudes. This gave rise to a variety of “hacks” where folks were their rheostat controllers to kinda follow the high altitude adjustment procedures outlined by Webasto. But, they conveniently left out the part where Webasto says to verify the C02 % with an exhaust gas analyzer after the adjustment to make sure you are within specification. In our testing, and as you might guess, this basically doesn’t work right. You’ve made an adjustment but it’s arbitrary and creates its own problems (more on that coming soon). How We Do It Correctly Comparing Standard Heater to an Altitude Adjusted Heater Still Curious? Download Test Results / White Paper More Information on the VMACS Website
Learn more
Webasto SmarTemp 3.0 Controller Overview Video
In this short video we take a look at the SmarTemp 3.0 Digital Controller for Webasto air heaters. This controller replaces the older 2.0 version of the SmarTemp and was released in 2022. The 3.0 adds Bluetooth connectivity that can be paired with a free Android or iOS app. You may also be interested in our Webasto Air Top 2000 STC vs. EVO 40 comparison video. Or our Webasto heater installation tips & tricks video.
Learn more
Video: Tetravan Shower Overview and Unboxing
One of the biggest questions in camper van design is whether or not to install a shower inside your van. Some people simply can’t live without an inside shower, while others are perfectly happy showering outside, at the gym or at campgrounds. The biggest issue with installing a shower inside your camper van is the amount of space it takes up. Another issue is that having a shower inside your van can also limit your floor plan and make it feel cramped or claustrophobic. On the flip side, the problem with NOT having a shower inside the van is that it can be inconvenient to take outdoor showers when in the city or when it’s cold outside. It can also sometimes be a hassle to find a gym or campground nearby that you can take a shower at. The best “compromise” solution we have found is the Tetravan Shower System which is a collapsible shower that folds away when not in use. It provides all the benefits of having a shower inside your van without any of the space and floor plan limitations usually associated with an interior shower. In addition to the shower itself, a really well made folding shower curtain that works seamlessly with the shower is included. Vanlife Outfitters has been selling the Tetravan shower for quite some time and our customers have been very happy with the product – so much so that we are installing this into one of our demo vans. In this video, we go over the product benefits and how it works. We also plan to do a video on how it’s installed at some point in the near future.
Learn more