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Kick The Tires And Light The Fires: Turning On Your Camper Van Electrical System For The First Time! Part 2
If you’re building a camper van electrical system, or planning your vanlife power setup, the first power-up is a big milestone. This blog is Part II of a two-part series on powering up your camper van electrical system for the first time. Part I discusses steps to think about before or during your build, and Part II focuses on the steps to energize & configure your mobile power system. To be honest, planning for & commissioning your electrical system is a process, so if you missed Part I, give it a read first before diving in here. This blog hopes to provide some of the why to go along with the what when commissioning your electrical system. Your build is progressing, and you're almost ready to Turn. It. On. Does it feel a bit daunting? Turning your electrical system on for the first time can be as exciting as putting that first hole in your new rig. How many times did you measure before you cut? Working methodically to power your system on is the same idea! It's going to be okay, and here is a checklist for getting your system up and running. Every system is different, and you can find a bunch of different how-tos on the interwebs. Some manufacturers provide commissioning steps in their manuals too, as an example this procedure is a good list even if you don't have a Victron BMS. You did read the manuals for your equipment, right? Here’s our take on a solid approach to getting your electrical system up and running. Double check At long last, can we finally get on with the steps? Yes, of course, as long as you consider checking your connections as part of the turn up sequence. Incorrect wiring can cause damage. This section is called double check, but we really mean triple check. Step 1 - Test Your Lugs, Terminals & Ferrules Check that your lugs and ferrules are done properly. You are not trying to treat those connections with "kid gloves" either. If you can yank on a lug and it comes off, that's not good! You're relying on those connections to handle high currents and keep you safe. Lugs, ferrules and terminals should be secure and difficult if not impossible to remove with a simple pull. Let’s briefly touch on ferrules too, which can be new or difficult for some customers. Since tinned, stranded wire from brands like Ancor is preferred for environmental & vibration tolerance (e.g. your safety!) in mobile power systems, wire ends for screw terminal connections should use a ferrule. Generally, a hex ratcheting ferrule tool is preferred, as the round shape formed after the crimp fits best in most screw & spring clamp terminals. In some cases, for instance with the Orion XS DC-DC chargers using the recommended 6 AWG wire in our free example wiring diagrams, only a hex crimped ferrule will fit (and a square crimped ferrule will not due to the resulting shape). The Victron Multiplus II inverter/charger AC terminal blocks require 18 mm bootlace ferrules that are longer than what is provided in most ferrule kits, and using shorter ferrules may cause the terminal block spring clamps to come loose. Do yourself a favor and use the correct ferrules, even if you need to go replace a few connections before powering on your system. Part of double checking can include learning that a few minor changes can go a long way to improving the safety and reliability of your system. Step 2 - Properly Tighten Your Connections Not only do your connectors need to be done properly, but those connections must be tightened properly. Properly means that you're not a tire jockey tightening nuts with your air wrench! Whether it's Victron, Blue Sea, or any other manufacturer, your device manual provides torque specifications for the connections. If you don't already have one, we recommend a torque wrench that you can pair up with any standard socket set and this tool for torqueing screw terminals. Step 3 - Review Every Connection in Your Wiring Diagram Review your wiring diagram. Review our complete set of example wiring diagrams. Depending on your system, you may use sections from more than one diagram. We recommend printing out your diagram(s), then highlight each wire & connection as you go through the double check on your system. While you're in the diagram, you did note all of the case & chassis case grounds, right? These safety connections are not optional. Check your MPPT case ground, your Multiplus PE connection, and of course your vehicle chassis ground connection. Step 4 - Check Your Fuses & Breakers Are all your fuses and safety devices installed? Remember that a fuse is sized to protect the wire. Double check that the correct fuse rating is installed in every location. Check your circuit breaker sizes too, and since we're almost ready to turn things on, go ahead and flip those breakers to the off position for now. Here's a quick tip for the Lynx Distributor: if you're not using every Mega fuse position in the Distributor, the LED will remain orange and not a happy green. With a Lynx Shunt or Lynx BMS connected to a Lynx Distributor, an empty Mega fuse slot will show up as an alarm because a blown fuse (i.e. an open fuse) looks no different than a missing fuse. We recommend mounting spare fuses in your unused Mega fuse slots. Hopefully you'll never need them, but maybe you'll be glad to have one handy in the future. Step 5 - Test Wiring with a Multimeter Use a multimeter to triple check those connections. Just to be clear, we're doing all of these checks before the system is energized! Check each load branch wiring for no "dead shorts", where the power and ground wires should show resistance and not be shorted together. Same for the AC wiring, where the hot and neutral should not be shorted. (Keep in mind that a Multiplus inverter/charger contains a ground relay that automatically connects neutral to the chassis ground if no AC input is supplied, so those AC wires may read as shorted.) Step 6 - Wrap It Up As you are wrapping up your double checks, it’s a good time to cover any exposed terminals to prevent damage from any accidental tool drop. Dress your cables with cable ties to minimize vibration and torque on equipment connections. Checklist for your wires and safety devices Test & inspect that you properly crimped your lugs, terminals, and ferrules Check that your connections are torqued to manufacturer specifications Review your wiring diagram and mark off that all wiring connections are as intended Check that your fuses & breakers are sized properly Test wiring for shorts & opens using a multimeter Install cable housings and cover any exposed terminals Finally! This is the moment where it all comes together. Start will all equipment switches turned off. Make sure the master battery switch or contactor in your BMS is off. If needed, temporarily remove fuses to keep sources and loads un-powered. Make sure your Multiplus inverter/charger switch is in the off position. As a reminder from Part I, we’re presuming that your batteries are fully charged before reaching this step. Work methodically! If something doesn't look right as you go through the steps, stop and assess. It's okay to power down, make a fix, and start over. And if you listened to our guidance for working on a testbed prior to a full camper van system, do as many steps as feasible...then get back to testing & building that rig! Here is our recommended turn-on procedure: 1) If your batteries have an on/off switch, go ahead and turn them on. If your system has a BMV-712, check your battery bank voltage now. Also check your battery using the manufacturer’s app if it has Bluetooth support. You’re looking to confirm that the batteries have no alarms and show very similar voltage readings. This tells you that your battery bank is successfully connected and ready to serve as an energy source for your system. 2) Turn the master switch or contactor on. Use a multimeter and check the voltage on your Lynx Distributor, it should (nearly) match your charged battery voltage. Use the battery and/or BMS app to check the battery voltage, current (should be a low number), and status. If you haven't already, make sure your battery BMS firmware is up to date. Some customers with a Victron BMS may run into a snag here and notice a pre-charge error. The BMS can be sensitive to capacitance and loads, particularly in complex systems with a Multiplus inverter/charger, a secondary alternator, or many other connections on the Lynx Distributor. If you get a pre-charge error, first check for real problems such as a short or incorrect connection on the distribution. If the connections are okay, you may need a simple workaround to sidestep the pre-charge error. One method is to enable one of your charging sources (see Step 4) to power-on the distribution side of the BMS before enabling the BMS contactor. This workaround pre-charges the distribution with a source other than the batteries through the BMS, therefore the BMS will correctly finish its turn-on sequence with no errors. Most customers can leave their system in on or standby modes after the commissioning steps are complete, so the pre-charge workaround is just a temporary annoyance. 3) If you have a Cerbo GX, it should be powered-up through your distribution. On your touch screen or app, check your Devices list and make sure your battery monitor is reading properly. This confirms that your shunt connection (either VE.Direct to a SmartShunt or CAN to a BMS) is correctly done. If your batteries have "Victron communications", also check your Cerbo Devices list to verify that your battery(ies) are present. You may need to change the CAN bus profile setting in your Cerbo GX to match your batteries and get Victron communications established. 3plus) Give your Cerbo GX some internet access! This step helps provide troubleshooting information for all the subsequent steps and makes it easy for you (and easy for us to help you). Ultimately, get access to your electrical system using the VRM as discussed in this blog. Using the touchscreen, connect to a WiFi network and set up the VRM. Make sure your Cerbo has the latest firmware. 4) Turn on charging sources one at a time. The order of charging sources to enable is not critical, but we suggest prioritizing the Multiplus inverter/charger, solar, DC-DC charger(s), then the secondary alternator kit. For each charging source, use the following steps: Check your battery monitor. Charging current should increase (and be a positive value) when the charging source is on. Check your Cerbo Devices list to make sure the device is communicating with your system. Update the firmware. Check and/or update the configuration to match manufacturer specifications. Periodically check your cables by hand or with a thermal imager. When charging heavily, some cables may be warm to the touch but not crazy hot. After checking one charging source, turn that source off and iterate on a different charging source. Keep it simple and methodical to safely check each part of your system. Once you've individually checked out each charging source, then you're ready to turn on multiple charging sources. There are some things to watch out for when turning on your charging sources. Apply battery power and turn on your Multiplus before connecting shore power. Here are some tips for programming your Multiplus. Charger settings: The devices do not come preconfigured for lithium batteries, so change that charge profile! Inverter settings: We recommend that the low voltage shutdown thresholds are set slightly higher than your BMS low voltage disconnect value. The inverter should turn off before completely discharging the battery bank, which could turn off your entire system. General settings: The default AC input current limit is 50 Amps, which is too high for most DIY garages & driveways using a standard 15 Amp household receptacle. Set that current limit before applying shore power, and let's not pop your circuit breaker or potentially damage your shiny new Multiplus, please?! We touched on solar in this blog. Your Victron MPPT PV (photovoltaic) voltage must be 5 Volts higher than your battery voltage for a charge cycle to start. Check that your alternator-based charging sources turn off when the engine is off but turn on when the engine is on. You want to ensure that your camper van starter batteries are not depleted by leaving a DC-DC charger on with the engine off. Our Victron & Sterling DC-DC chargers can be configured to detect voltages, detect vibration, and/or utilize external "remote" on/off connections to keep your van's two battery systems properly isolated. VictronConnect tip: After connecting to a MPPT or DC-DC converter via Bluetooth using the VictronConnect app, if your device is powered on but in the off state (i.e. not charging), you will see a Why is the charger off? line on the status page. Victron tells you the reason your device isn't charging, and that can be pretty handy! Even with your battery switch or BMS contactor open, any charging source that is enabled will energize your Lynx Distributor. Why? Because your charging sources and your loads are interconnected on your distributor. Your master battery switch or BMS contactor separates energy stored in your battery bank from the distributor but does not disconnect the other sources of power. Be cautious while testing or doing maintenance, and make sure that all batteries and charge sources are off when required. DVCC tip: DVCC is an algorithm running in your Cerbo that intelligently coordinates your smart charging sources to provide only the charging current desired by your batteries & BMS. It's not quite magic, but testing with DVCC enabled can yield confusing results. Typically, if your batteries are mostly full (above the SoC threshold, State of Charge in your battery monitor), then your charging source(s) may be throttled to optimize battery lifecycles. Don't panic if your DC-DC charger doesn't put out a full 50 Amps in that case. Another source of throttling is heat, so testing mid-summer in high ambient temperatures may limit charging performance. You may need to move on to the next step, enabling loads to discharge your battery bank with charging sources off, then return to re-examine your charging performance with a lower battery SoC. Need troubleshooting help? Don’t forget the cutting it in half approach as discussed in Part I. Our tech support team has tons of vanlife experience, so we’re here to help too. 5) Turn on loads one by one. Work through your checklist of all AC and DC loads. For each load, check with a voltmeter and look at your battery monitor or touch screen display. You should see an appropriate increase in AC or DC Wattage for each load. If your load reporting looks incorrect, double check your cabling, especially the chassis ground. Only the battery cables should be on the Battery Minus terminal of your BMS & shunt, and every other connection (like chassis ground!) should be on the distributor side. As with your charging sources, inspect your distribution and load cables & connections for excessive heat. 6) Check your battery monitor (i.e. shunt). Now that you can comfortably charge and discharge your batteries, make sure that your battery monitor is properly configured. In Victron-speak, you want to allow a successful synchronization so that the battery monitor correctly reports your SoC. After the first power up, the battery monitor may not show the correct SOC. To reach a synchronization (which can be checked using the VictronConnect app under History), first discharge the batteries to around 50% SoC using your loads, then turn off your loads and charge the batteries to 100% using a charging source (such as shore power which typically provides the fastest charging). Allow your system to complete a full lithium charging profile, transitioning from absorption (higher, constant current) to float (low current, constant voltage). If your battery monitor reports 100% SoC and shows a synchronization event, your battery monitor is properly configured and will provide correct SoC reporting. This step also ensures that any paralleled batteries in your battery bank are balanced, promoting equal sharing of the charging sources and loads from your batteries to prolong battery lifecycles. 7) Use your system and enjoy! Take advantage of the VictronConnect app and VRM to monitor your system performance. While this blog is about turning on your system for the first time, many customers are already thinking ahead about maintenance & battery storage. Self-discharge of lithium batteries is quite low, so typically we recommend that you don’t need to completely turn off your system when not in use. If you have internet access and are using the VRM, then leaving your system on and idle is quite helpful for remotely checking in on your rig. You may find it handy to turn your Multiplus inverter/charger to Charger mode, which disables the inverter and saves you the 20-30 Watts of idle power from being constantly consumed while you’re not using your system. To maximize your battery lifecycles, it’s recommended that lithium batteries are stored between 50%-70% SoC. Most importantly, lithium batteries have improved lifecycles when not exposed to high currents near 100% SoC. In other words, don’t leave your system plugged into a charging source constantly with your batteries at 100% SoC. If you have a system with Victron NG or Smart batteries with DVCC enabled, the good news is that your system is automatically being optimized and you don’t need to take any special storage precautions. Victron automatically keeps the SoC optimized while allowing charging to 100% once per month, which keeps the battery cells balanced. For more basic or value battery-based systems, you may need to be a little more mindful about lithium battery storage. You may wish to manually enable/disable charging sources to manage your battery SoC. If you can store your electrical system with shore power, an alternative is to adjust your configuration profile to a lower absorption voltage that will limit charging to around 70%. Don’t forget that you need to charge up to 100% every month or so to keep those battery cells balanced. Change your system configuration into normal mode to allow charging up to 100%, then return to a storage mode configuration until you’re ready to use that rig. Don’t forget to change back to normal mode to get the most performance out of your electrical system while you’re on that trip! Super-condensed power-on checklist Start will all loads and charging sources off Pre-charge your batteries and make parallel connections before turning batteries or battery switch on At each step of your power-on, use your device’s Bluetooth app and a multimeter to check status & power. Also check for excessive cable heating Use your battery monitor to check battery voltage, status, and current Update firmware on each device as you go If applicable, use your Cerbo to check that device communications are established. Set up your Cerbo VRM for remote monitoring and troubleshooting Turn on charging sources one at a time. Test each charging source by itself before using multiple charging sources together Turn on loads one at a time After checking your charging sources and loads, take your system through several discharge then charge cycles to balance your batteries and synchronize your battery monitor Don’t forget that storing & maintaining your batteries should be done at a lower State of Charge than your typical 100% pre-trip SoC Summary Successfully powering up your camper van electrical system for the first time is all about being methodical. There are four major steps in planning for & commissioning your system: Prepare your batteries Get familiar with your system with bench testing & incremental building Double check your wiring and connections Power up your batteries, charging sources, and loads in an orderly fashion, checking for voltage & heat at each step. Configure each device as you go. FAQ: Commissioning & Configuring Your Camper Van Electrical System What should I check before powering up my electrical system?Inspect every lug and ferrule, check torque specs, confirm correct fuse ratings, and use a multimeter to ensure there are no shorts between positive and negative wires. How do I safely turn on my camper van electrical system for the first time?Start with all switches off. Confirm battery charge and all connections before powering up. Power on your batteries then the master switch. Verify voltage before enabling charging sources or loads. How do I configure my Victron Multiplus inverter/charger for lithium batteries?Use the Victron VEConfigure software to change the charge profile to lithium, set inverter low-voltage shutdown slightly above your BMS cutoff, and reduce the AC input current limit to suit your shore-power source. What recommended order should I turn on my charging sources?Start with the Multiplus inverter/charger, then solar MPPT, DC-DC chargers, and finally any secondary alternator kit. Test one at a time before enabling them together. Why is my Victron BMS showing a pre-charge error?This can happen when capacitance or load prevents proper pre-charge. First check that there are no shorts on your Lynx Distributor. Enable one charging source to energize the distribution side before closing the BMS contactor, then retry. How do I synchronize my Victron battery monitor (BMV-712 / SmartShunt / Lynx Shunt / BMS)?Make sure to use a lithium-ion charging profile on your charger. Discharge batteries to ~50% SoC, then fully recharge until absorption transitions to float. Once the monitor shows 100% SoC and logs a “synchronization” event, calibration is complete. This can take some time, so be patient. How should I store lithium batteries in my camper van? Keep between 50–70 % SoC, avoid continuous charging at 100 %, and store in moderate temperatures. Systems with DVCC or Victron Smart / NG BMS manage this automatically.
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The Calm Before The Storm: Powering Up Your Camper Van Electrical System The First Time! Part 1
If you’re building a camper van electrical system, or planning your vanlife power setup, the first power-up is a big milestone. This blog is Part I of a two-part series on powering up your electrical system for the first time. Part I discusses steps to think about before or during your build. We hope you’ll give this a read, hopefully before you need Part II that focuses on the steps to power up & configure your mobile power system. To be honest, planning for & commissioning your electrical system should be an iterative process, so give both parts a read and let’s get to it. This blog hopes to provide some of the why to go along with the what when planning for your camper van electrical system. Planning for that first power-up involves two major pieces. One step is having your batteries charged & ready. The second step is a bit more involved, and that’s thinking ahead (thus the planning keyword) and gaining familiarity with your equipment as part of a testbed. Prepare your batteries We recommend charging your batteries before wiring them into your camper van electrical system. If you have batteries in series (not something we recommend often at this point with great battery options available at 24 and 48 Volts), then charging the batteries & balancing the internal cells is required. Here's an excerpt from Victron on why, and yes this is a prod to Read. The. Manual. for all of your equipment. The Victron manuals are an exceptional resource, and reading through your manuals makes sure that you understand the features, installation requirements, and safety guidelines for your equipment. When using batteries in parallel, it's still a good idea to charge them first. Charging those batteries individually is a good idea too. After charging, check each battery’s voltage with a multimeter to confirm that they are at the same voltage. It’s typically not possible to get them exactly the same, but charging with 0.1 Volt (closer is better!) is sufficient. Charging each battery separately to the same voltage helps minimize current flow between batteries when they are later connected in parallel, which is important to prevent damage caused by high currents from connecting different voltages. Lithium batteries are not shipped fully charged, so charging your batteries also provides more capacity so that you don't feel rushed during the steps covered later in this blog when turning on your equipment. Deeply discharging your batteries, also referred to as undervoltage, can be damaging to lithium batteries (moreso than overcharging that is typically protected by the BMS!), so there's another reason to give yourself plenty of margin during your turn on process. It's critical that your batteries are charged with a proper charge cycle, and the batteries should be charged through your Battery Management System (BMS). If you have selected batteries with an external BMS, that means you need to connect your battery and BMS to charge each battery. Whether your lithium battery has an external or internal BMS, use a charger with a lithium-ion profile and be careful to monitor temperature and overcharging during this step. This is a perfect segue into the next step (or is it the first step?!), which is working on a testbed for your electrical system. If your batteries have Bluetooth and an app, this would be a good time to use it. Connect to each battery and look at the status. Do your batteries say fully charged (100% State of Charge, SOC) and balanced? Yay! Some customers find it easiest to use an external battery charger to initially charge their batteries. Using an external charger is simple - just plug into a standard AC receptacle for power and allow each battery to go through a complete charge cycle (go through a bulk stage and get to the low current float stage in lithium batteries). If the compelling reasons to build a testbed below don't sell you, then an external battery charger may also be your best option to get those batteries charged before turning on your system. Our recommendation is to combine a test setup with your initial charging step, and use one of your system charging sources (particularly your Multiplus inverter/charger) to initially charge each battery. More on that now... Checklist for preparing your batteries Charge each battery individually using a full lithium-ion profile Use a multimeter to check each battery voltage Confirm BMS status and 100% SoC using the Bluetooth app Testing, testing, 1, 2 This camper van build is already a ton of work, and now you're suggesting that I build it twice!? To some degree, yes. If you're finding this blog after your build is done, then you could skip this section. Hopefully you'll read on and see why testing early is important and helpful. Bench testing doesn't mean that you have to build a complete system either. Go piecemeal. Our recommendation is to slowly add one piece of equipment at a time. Start with your batteries and BMS, add your Distributor, add a charging source, then turn add & turn on a load. Continue that methodical approach with other charging sources & additional loads. If you choose, test something then tear it down and test something else. You don’t need your testbed fully functioning, for example it’s okay to add a DC-DC charger or MPPT without the “source” connection. Your device will still turn on once energized, and you can start using your equipment and complete the configuration step. The whole point is to get familiar with your (future) system. Why bench test? Practice the physical connections. This is your chance to get familiar with the connections on your equipment. Many customers are stripping, crimping, and properly torquing cables for the first time. It's perfectly reasonable to throw away a test lug or two...aren't you better at something after a little practice? Particularly with the high current connections in these electrical systems, it's important that the connections are done properly. Learn that your layout can be improved. After assembling some of your equipment, it's just easier to visualize how it all fits together. How do I minimize my battery cable lengths? Gee, these 4/0 cables need a bend radius. Maybe a ML Link would be easier than a cable? Oh, the touchscreen cables aren't long enough, and it needs to be closer to my Cerbo. These are just some examples of lessons learned that are easier to resolve before your build is underway. Forget something? Testing and using your equipment before your build is "done" can reduce your panic later. Need fuses for your Lynx distributor? Need an extra VE.Direct cable so your equipment can communicate? Have everything in imperial (SAE) but one item has to be metric...and you're off to the store again. It's easier to troubleshoot and resolve issues in a testbed. Moving cables, accessing equipment, or even starting over is so much simpler before the equipment is installed in your rig. And if you’re following our advice to incrementally build & test equipment, problems are presented immediately with an obvious example of cause and effect. The manufacturer says so. We've already discussed why you should charge your batteries first. Nomadic says "always bench test AC unit before installing". Other vendors do too. Yeah, we know, those annoying manuals again. Work through failures early. Yes, we had to go there. Sometimes a mistake is made, and you need a new fuse, or worse, a new piece of equipment. Didn't notice some shipping damage inside the box? Some unlucky few experience the dreaded Dead On Arrival equipment, which is quite rare but a super bummer to deal with. Find out early by bench testing, and don't wait until you're rushing to be ready for that first road trip. Consider purchasing a small power supply (bonus tip: the external battery charger discussed above can also operate as a power supply to run DC loads). With a power supply, you can test easily without worrying about your battery cycles. Run your water pump and test those fittings, get familiar with your Cerbo and get the VRM ready for troubleshooting, trial your LED lighting or dimmer switches, the list is endless, but building familiarity with your equipment will save time & heartache later once it's in your rig. If you're still not sold on a separate testbed, then at least consider building and testing your system incrementally rather than all at once. It's so much easier to isolate problems when something works, you add a piece of equipment, then something doesn't work. That narrows down your focus to what's new rather than staring at a complete system with no clue as to where to begin. These electrical systems can be complex, and despite a methodical approach some problems may not be easy to identify. In case you run into problems, here’s a super secret (not really) testing tip: make a complex problem easier to solve by cutting it in half, meaning make methodical changes to remove components and narrow down the potential problem. This is also called divide and conquer. Some ways to cut it in half may be to: Remove charging sources one by one. If the problem persists, a removed source isn't likely to be your problem, or if the problem is resolved, that recently removed source may be your issue. Remove loads one by one. Same idea as removing charging sources: is a particular load causing you trouble? Replace a source or a load with an identical copy. This approach can help rule out physical or device problems, but be careful that software or configuration of many devices can be related to the problem. If you replace one device with an identically configured copy and the problem changes, then you're making progress towards finding the culprit. If you replace one device with an identically configured copy and the problem doesn't change, you may not have learned anything, or maybe it's time to try configuration changes. Change firmware versions or software configuration items one at a time. Change, test, repeat. Change, test, repeat. If you change 27 settings at one time and something behaves differently...did you identify the problem or just change the scenario? Or even if you did come across a configuration setting that was important, which of those 27 settings was the one? Whether you’re working on your testbed or in your rig, our tech support team is always available to help you, and you don’t have to wait until you’re “done” to reach out to us. In fact, it’s probably easier on you and us if you’ve been working methodically and have more info to get us started than ‘it’s broke,fix it’. The bottom line is that after building a testbed you're going to be better at doing something the second time than the first. You’ll be comfortable with your equipment, you’ll have confidence in your system, and you’ll be off enjoying vanlife on your first road trip sooner by planning ahead before powering up your system for the first time. Common mistakes to avoid Not using bench testing to improve your van’s build - practice those connections first, and any bench test error is simply a “lesson learned” that will make your build better and safer Building out everything, then being overwhelmed about where to start - it’s okay to be methodical and build confidence in yourself as you incrementally build & test your system Making access for maintenance difficult or impossible - connections need to be periodically inspected, or maybe you realized that a mistake was made during commissioning. Do yourself a favor and plan ahead for the capability to access & inspect your equipment after install. Summary It’s important to plan ahead before powering on your camper van electrical system for the first time. Charging your lithium batteries fully with a proper charge cycle gets you prepared to start connecting other equipment. We suggest you work methodically and consider a testbed prior to your van build, or alternatively build & use your power system iteratively. Using a testbed helps you: practice the physical connections plan an optimal layout of your components configure and test your equipment make it easy to troubleshoot issues Next Step Ready to power up? Check out Part II for step-by-step guidance on commissioning and configuration. FAQ: Powering Up Your Camper Van Electrical System for the First Time 1. Why should I charge my camper-van batteries before installation? Lithium batteries are typically shipped partially charged, not full. Charging them before installation ensures all cells are balanced and the voltages match across batteries. This prevents high current surges when connecting them in parallel and gives you full capacity when testing or powering on your system for the first time. 2. Do I need to charge each lithium battery separately? Yes – it’s best to charge each battery individually until their voltages are similar, at least within about 0.1 Volt of each other. Doing this minimizes current flow between batteries when connected in parallel and reduces stress on your system. It’s also a great opportunity to verify that each battery and BMS is functioning properly. 3. What’s the safest way to charge lithium batteries for a van build? Use a charger designed for lithium-ion profiles and always charge through the Battery Management System (BMS). Monitor temperature and voltage to avoid overcharging. Many builders use an external charger or their inverter/charger (like a Victron Multiplus) to perform the first full charge. 4. What is “bench testing” or a “testbed” for a camper-van electrical system? Bench testing means assembling and powering your electrical components on a workbench before installing them in your van. It lets you practice making cable connections, confirm proper wiring, configure settings, and verify that devices communicate and operate as expected. This reduces installation surprises and makes troubleshooting far easier. 5. How do I build a simple testbed for my van electrical system? Start small. Connect your batteries and BMS first, then add one component at a time – a distributor, then a charging source, and then loads. Power up each addition separately to confirm correct operation. You can use an external power supply to run loads without cycling your batteries. 6. What are the benefits of testing my system before full installation? Testing early helps you: Practice safe, solid cable terminations Optimize layout and cable lengths Confirm that your components communicate properly Catch missing parts or incompatibilities Identify defective equipment before it’s permanently installed 7. What are common mistakes when turning on a van electrical system for the first time? Skipping the initial battery charge and balance Connecting batteries with mismatched voltages Over-tightening or under-torquing high-current connections Failing to label or document cable routes Powering up everything at once instead of one step at a time 8. How can I troubleshoot issues during the first power-up? Take a divide and conquer approach: Remove charging sources or loads one at a time to isolate the issue Replace a suspect component with a known-good on. Revert firmware or configuration changes step-by-step Use your device apps (e.g., VictronConnect or VRM) to check for abnormal readings 9. When should I reach out for help with my van electrical system? If you’re unsure, don’t wait until something goes poorly. Contact our Technical Support Team before you’re “done.” We can help confirm settings, review the manuals, and troubleshoot issues faster when you’ve been testing methodically.
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How To Choose Solar Panels For Your Camper Van
This blog details the steps we suggest to pick solar panels for your rig. First step, play Tetris! How much space do you have available for solar panels on your roof? Start by determining if you will be mounting your solar panels to a roof rack, OEM roof rails with crossbars, or some other method. Mounting solar panels using Z brackets to crossbars is our go-to approach. Take away space for your vent fan(s), rooftop air conditioner, Starlink mount, recovery boards, rooftop deck, or other rooftop accessories. That remaining space (hopefully there is some left over!) can get filled with solar panels. Just like all of the tradeoffs inside your rig, you have to make tough decisions on what can fit on top too. Here’s the part that’s not as much fun as it sounds: play panel Tetris, looking at the dimensions of the solar panels while trying to maximize the usable space. Different vendors may have different dimensions for the same panel wattage. Roughly speaking, you will find that panels with lower wattage ratings are correspondingly smaller. Remember that you’re trying to maximize the rooftop area covered with panels, so selecting a smaller panel may allow you to fit more total wattage on your roof. Also keep in mind that mixing different panel sizes is not recommended, so you’re trying to maximize the number of identical panels to fill up your rooftop space. We find that solar arrays like this Newpowa 220 Watt panel with the long side dimensions of <57″ fit well to maximize the horizontal rooftop space on a van. Because of all those other must-have items, many customers may settle for a 400ish Watt array using two panels mounted horizontally. The good news is that the above steps are where all the tough decisions have to happen. The rest is “easy”. Let’s talk about panel voltage Solar panels are marketed in 12 V and 24 V options. One manufacturer’s 12 V nameplate does not mean that another manufacturer’s 12 V specifications are identical, and in fact those specs can vary greatly. 48 V options in solar panel sizes fitting vehicles are not readily available at this time. You picked a 12 V battery bank, you picked a 12 V inverter/charger, so naturally you pick a…well sorry to confuse you, but with solar panels the nameplate voltage doesn’t really matter. What does matter are a few details: The specifications of the solar panel, particularly the Voc, or the open-circuit voltage which is the maximum voltage that the panel will produce How the panel(s) are wired, in series or parallel. Wiring panels in series increases voltage, and wiring panels in parallel increases current. Hopefully a quick set of examples will clarify this confusion. Take a look at the Newpowa 200 Watt 12 V panel specs, and compare those specs to the Newpowa 200W 24 V panel. The 12 V panel has a Voc rating of 24.34 Volts, while the 24 V panel has a Voc rating of 48.68 Volts. You may be thinking those voltages are so high, how can either of these panels work with my 12 Volt electrical system!? The key is that the MPPT charge controller converts the PV (photovoltaic, i.e. solar) side voltage to your BATT (battery) side voltage. In fact, you want the PV side to be a high voltage to allow smaller cables, minimize voltage drop, and minimize losses. Can I use 24 V solar panels in a 12 V system? Yes. Using a 24 V panel like the Newpowa 200 W 24 V panel in a 12 V system allows you to either use panels in series for more efficiency or use panels in parallel for better partial shading performance (or both! two series panels with two more series panels in parallel). In a small solar array, even using only one 24 Volt panel can still work well for a 12 V system. Can I use 12 V solar panels in a 24 V system? Yes, with a caveat or two. In order for the MPPT charge controller to start a charging cycle (in other words, for the MPPT to become a useful device by turning on and supplying power to charge your batteries) the PV voltage must be higher than the BATT voltage. In Victron MPPT charge controllers, this voltage difference must be more than 5 Volts. Using two or more Newpowa 200 W 12 V panels in series meets that requirement in a 24 Volt system, as the PV voltage becomes much higher than the nominal battery voltage. Can I use 12 V or 24 V solar panels in a 48 V system? Yes, with the same caveats as above. Especially with 48 V systems that are typically paired with a secondary alternator kit to rapidly recharge while using a rooftop air conditioner, there may not be tons of space on the roof for solar. That’s just one of the tradeoffs when selecting a 48 V system. Solar arrays with three or more 12 V panels in series or two or more 24 V panels in series are typically required in 48 V systems. Picking a MPPT charge controller Victron MPPT charge controllers have two numbers on each device (for example, 100/50), and here’s the breakdown on those numbers: The first number is the maximum voltage that the controller can tolerate. Do not exceed the nameplate voltage rating or device damage may occur. Also note that the Voc rating discussed above is a nominal value, and the actual maximum voltage varies with temperature. Each solar panel manufacturer provides an additional rating for temperature coefficient for Voc (or another similar name & specification). The second number is the maximum current that the controller can source to your batteries. If you have more solar power available than the maximum current rating, no damage occurs but you don’t get to use all of the available power. Because our solar panels are seldom oriented perfectly at the sun, and you only get so many days of ideal solar panel per year, a slightly undersized MPPT charge controller may not be noticeable to your charging performance. These two MPPT numbers sound a little complicated, so use a cheat sheet. And by cheat sheet, we mean this great MPPT calculator from Victron. Here’s the best way to use the MPPT calculator: 1) Start typing your solar panel vendor and SKU in the Solar Panel field. If you’re in luck, your solar panel model is already in the list. If not, try 1a. 1a) Okay, your model didn’t show up. No problem! Find the Advanced Panel Settings slider and enable advanced mode. 1b) Act advanced. Seven panel specifications become available for editing, and for most manufacturers you need to copy & paste those seven specifications from their panel datasheet to the calculator. Pretty advanced, huh!? 2) Set your system Voltage to 12/24/48. This setting is your battery voltage, because we already told you panel voltage is pretty meh 3) Adjust the Series and Strings parameters to yield the number of panels you can fit. Series is obvious, increase this number if you need/want panels in series. Strings means parallel, increase this number for more Y-branch connectors and panels in parallel. It’s okay to play around with these settings too, adjust series or parallel values and see what the calculator tells you. Some panel configurations offer you a tradeoff, while others just require you to wire your solar array a specific way to make it work. 4) Bonus choice: set your location to see an estimate of how much daily yield your solar panel may provide. But you’re in a van and traveling the world, so maybe you care more if it’s going to rain tomorrow than what your yield would be if you parked in Albuquerque for a month? Now look on the right side of the calculator for the Result. Victron tells you the best MPPT charge controller for your array, and they show you lots of fun details why it’s the best controller too. Yay! For some customers, especially those on larger rigs like trailers, going with two MPPT charge controllers with two types of panels may be a useful choice to maximize area. Using two MPPT charge controllers is also a good choice for “ground deployed” solar panels that get temporarily set up in conjunction with fixed rooftop panels. And, you get to play Tetris and use the calculator twice. Fun times. Wrap up Maybe you’re the TL;DR type, but we hope you read through the details above. To wrap it up, we suggest the following steps to pick your solar panels: 1) Play Tetris with your panels to fit as many identical panels as possible on your roof 2) Use the MPPT calculator to select your charge controller That’s not hard! But if you run into any snags, our tech support team is always ready to help you understand more about our solar products and blogs. Contact us!
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Watt Hours Vs Amp Hours
Watt-Hours vs. Amp-Hours: What Every Van Builder Needs to Know If you’re building your own van’s electrical system, you’ve probably seen batteries advertised in amp-hours (Ah), while solar panels and appliances often list power in watts or watt-hours (Wh). Here’s the problem: mixing these up can lead to a seriously undersized system — and that’s how you end up with a dead fridge, no lights, and warm beer halfway through your road trip. By the end of this post, you’ll know exactly what these terms mean, how they’re connected, and how to use them to plan your off-grid electrical setup with confidence. Amp-Hours: The Current Over Time An amp-hour (Ah) is a measure of how much current a battery can deliver over time. Think of amps like the width of a water hose — the bigger the hose, the more water (current) can flow. Amp-hours tell you how much total flow you get over a certain period. Example: A 100Ah battery could, in theory, supply: 1 amp for 100 hours 5 amps for 20 hours 10 amps for 10 hours Key point: Amp-hours alone don’t tell the full story — you also need the voltage. Watt-Hours: The Real Energy Number A watt-hour (Wh) measures total energy — this is the true “fuel tank size” for your battery. Here’s the connection: Watts = Volts × Amps Watt-hours = Volts × Amp-hours So if you know a battery’s amp-hours and voltage, you can find watt-hours. Example: 100Ah at 12 volts = 1,200Wh 100Ah at 24 volts = 2,400Wh Why it matters: Two batteries can have the same amp-hour rating but store very different amounts of energy if their voltages are different. That’s why watt-hours are better for comparing systems. Example of our Victron LFP-12.8/300 packs nominal energy at 3840Wh Lithium Batteries can be found here: https://www.vanlifeoutfitters.com/category/camper-van-electrical-system-parts/batteries/ The industry is headed towards rating battery power by the nominal energy voltages. Instead of seeing 12, 24 or 48 volts the industry uses 12.8, 25.6 and 51.2 volts as the nominal values for watt hour calculations. Why Watt-Hours Matter More for Off-Grid Systems Amp-hours are useful when you’re staying in one voltage (most van systems are 12V), but watt-hours let you: Compare batteries of different voltages (12V, 24V, 48V). Calculate your daily power needs accurately. Match your battery capacity to your solar panel output and appliance usage. If you only look at amp-hours, you might undersize your system and run out of battery faster than you expect. How to Calculate Your Daily Power Needs Before buying batteries, figure out how much energy you use in a typical day. Here’s how: Step 1: List your appliances. Write down every device you’ll use: fridge, lights, fan, water pump, laptop, etc. Step 2: Find the wattage. Look for a sticker on the device, the manual, or search online. If it only lists amps, use: Watts = Volts × Amps Step 3: Multiply by hours used per day. This gives you watt-hours for that device. Step 4: Add everything up. That’s your daily total watt-hours. Example Daily Usage Table: Appliance Watts Hours/Day Daily Wh 12V fridge 50 8 400 LED lights 20 4 80 Vent fan 30 5 150 Air Conditioner 600 5 3000 Phone charging 10 2 20 Total — — 3650Wh Step 5: Add a safety margin. Cloudy days, inverter inefficiencies, and battery aging happen. Add 20–30% to be safe: 3650Wh × 1.25 ≈ 4,562.5 Wh/day needed. Converting Between Ah and Wh If you already know one measurement, here’s the cheat sheet: Ah = Wh ÷ Volts Wh = Ah × Volts Example: You need 4,562.5Wh per day. With a 12V system: Ah = 4,562.5 ÷ 12 ≈ 381Ah So you’d want at least a 460Ah lithium battery bank (lithium batteries can use most of their capacity, however manufactures only recommend 80% depth of discharge or less; lead-acid can only use about 50%). With your daily Wh usage calculated, remember you must have a charging source that is capable of replenishing the used energy each day too. This can be from solar, dcdc chargers, 2nd alternator, shore power or generator. Common Mistakes to Avoid Comparing Ah without checking voltage. A 100Ah 12V battery is not the same as a 100Ah 24V battery. Forgetting inverter losses. Converting 12V DC to 120V AC loses ~10–15% of energy. Only planning for sunny days. Always size for your worst-case scenario. Not tracking usage. A battery monitor like a Victron SmartShunt helps you see real-world consumption. Final Tips for DIY Van Builders Always start with watt-hours when planning your system. Use efficient appliances — LED lights, efficient DC fridges, and laptops instead of power-hungry desktops. If you can, test your system before hitting the road. Remember: you can always add more solar panels later, but battery capacity is harder to upgrade in a cramped van. Conclusion: Understanding watt-hours vs. amp-hours is one of the most important steps in building a reliable off-grid van electrical system. Once you get the hang of converting between them, you can size your battery bank, solar array, and charging system with confidence — and keep your lights on and fridge cold, no matter where the road takes you. If you need assistance putting together your electrical system, please call 754-444-8704 an agent at Vanlife Outfitters will provide their expertise in the perfect electrical system for your application.
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24V Camper Van Secondary Alternator Electrical System - More Options at 24 Volts!
Example 24V Camper Van Electrical System with Victron NG Batteries and Secondary Alternator Jump To Example Wiring Diagram Options. Voltage. Capacity. Charging methods. Brand. Topology. Are there too many options for your camper van electrical system? If your answer is Yes, then we’re here and happy to help. Reach out to us, and our goal is to help you understand more about our camper van electrical system bundles (or any product in our store!). We pride ourselves on actually responding to your emails or picking up your phone call. We may even be working from our vans while we’re doing it! Whether your answer above was Yes or No, this blog post is a reminder that you do have options. In particular, we’ve added to our suite of free example wiring diagrams to include a complete 24 Volt electrical system based on Victron NG batteries that can be paired with a high-power secondary alternator for charging. 12 Volt, 24 Volt, or 48 Volt? Shore power, DC-DC (primary alternator), secondary alternator, and/or solar charging? Yep, you can do that. Let’s talk about this 24 Volt Victron NG-based electrical system Options does not have to mean Complication. In fact, this 24 Volt NG electrical system for your camper van has CAN ( “controller area network“) communication so that you don’t need to fiddle with every device configuration to get the system working well – all of the major system components “talk” to each other and communicate with the batteries for safe, reliable and fast charging or discharging. In Victron-speak, these devices are Smart. This bundle can include a ~3,600 Watt (150 Amp) Nations secondary alternator plus an additional 700 W (or more) of DC-DC charging from the primary alternator. That’s a lot of charging power while driving. Sure, adding a little bit of solar charging can help keep up with those house loads too. As far as discharging, a Multiplus “3000” is still probably in the sweet spot, capable of surging up to 5500 Watts of AC load. What’s different with this system? Not a lot really. In the example wiring diagram, you’ll see many similarities to our 12 Volt and 48 Volt secondary alternator system bundles. Of course we’ve carefully selected 24 Volt equipment in this case. And there’s still some 12 Volts running around as discussed in this blog. If you’re considering a 24 Volt system, we expect that you’re selecting as many 24 Volt appliances as possible, but it’s hard to completely remove 12 Volts. Air conditioner, refrigerator, air heater, lighting, pumps,… the list goes on, and yep, you can do that at 24 Volts. The number of 24 Volt loads may turn out to be one of the more annoying issues to handle in this system. And it’s not that bad. You can easily expand the 24 Volt distribution with a second Lynx Distributor, but the distributor uses MEGA fuses that only go down to 40 Amps. The example wiring diagram shows a Littelfuse MIDI Fuse Holder that can provide an extra 2 or 3 loads with MIDI fuses that go down to 30 Amps. Rather than inline fuses for the multitude of smaller load branches at 24 Volts, it may make sense to use a DC fuse block wired from the Lynx Distributor. Many sizes of DC fuse blocks are offered by Blue Sea, including this one with six circuits. The primary non-Smart device shown in this system is the venerable Orion 24/12-70 DC-DC converter to supply that aforementioned 12 Volts. It’s possible to use the newer Smart Orion XS 1400 as the 24/12 converter instead. Using the XS 1400 gives you more visibility into your 12 V load consumption, and it provides the voltage conversion at a higher efficiency (maximum of 98.5% efficient versus 92%). Efficiency is the name of the game for a 24 Volt system, so for some customers the XS 1400 as the 24/12 converter can make sense. In the example wiring diagram, you’ll also find a small reminder that the Lynx Smart BMS NG provides an Allow To Discharge (ATD) signal. ATD can be used to stop devices from discharging the batteries, extending the “smart” operation of your system and protecting your batteries. We show a simple wiring example where the Orion 24/12-70 DC-DC converter is enabled/disabled by ATD, and that technique can be expanded using a Smart BatteryProtect. Here’s a hypothetical use for a Smart BatteryProtect: maybe you don’t want your high-power 24 Volt air conditioner to run your batteries flat overnight while you’re boondocking. Waking up with no power available is so much fun! How many times have I said System in this blog? Not enough, apparently. The key part of safe, reliable and fast charging is that your electrical components have been carefully selected and proven to be interoperable. Particularly in the case of the Nations secondary alternator with Wakespeed WS500 Pro regulator as a charging option, your electrical system should include batteries officially supported by Wakespeed to work correctly and safely. The Victron NG BMS & batteries, Wakespeed regulator, and Cerbo running DVCC (along with all those other Smart devices) perform as a system that has been tested, can be supported, and is proven to operate to meet your camper van’s demands. Wiring diagram and bundle Click below for the 24 Volt electrical system with secondary alternator kit free example wiring diagram. This system can be purchased through our build your own bundle page. You’ll get our best bundle pricing and fast & free shipping, and of course you’ll get the electrical system best tailored to the needs of your van. If you have questions about this 24 Volt camper van electrical system, reach out to us and someone from our tech support team will be happy to assist you. 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 24V Secondary Alternator Wiring Diagram for our example wiring corresponding with this blog post. Summary: 24V Camper Van Electrical System with Secondary Alternator Kit at a Glance A 24 Volt camper van electrical system with a secondary alternator is one of the most reliable ways to power high-demand, off-grid living. By reducing current and wire size, 24 Volt systems improve efficiency and make it easier to run heavy loads like air conditioning and refrigerators. Many DIY camper van builders still rely on 12 Volts for lights, fans, and pumps, but adding a 24 Volt alternator setup gives you faster charging and greater flexibility. If you’re planning a complete camper van electrical system, consider whether 24 Volt is the right balance of simplicity, performance, and long-term reliability. FAQ: 24V Camper Van Electrical Systems Is 24V better than 12V for a camper van electrical system? A 24 Volt camper van electrical system is more efficient for high-power setups. Because the voltage is higher, the current is lower — which means smaller wires, less energy loss, and better efficiency. A 12 Volt system is often enough for simple camper van electrical systems, but if you want to run appliances like air conditioning or refrigerators off-grid, 24 Volts is usually the smarter choice. Do I need a secondary alternator for my camper van electrical system? Not every van needs one. A secondary alternator kit is ideal if you drive or idle often and want reliable, high-output charging for a large battery bank. For smaller or simpler camper van electrical systems, a DC-DC charger connected to your stock alternator may be enough. In fact, both a secondary alternator and a DC-DC charger can be combined for massive charging power! Can I mix 12V and 24V in the same camper van electrical system? Yes — many builders do. A common setup is to use 24 Volts for high-draw loads (like heavy appliances such as air conditioners and refrigerators) and keep a small 12 Volt distribution panel for lights, fans, and pumps. This adds a little bit of complexity, but it’s a practical solution when you want the efficiency of 24 Volt and the necessity of 12 Volts. How much does a complete camper van electrical system cost? Costs vary depending on power needs. A simple setup might run $1,500–$3,000. A complete camper van electrical system with a large lithium battery bank, secondary alternator kit, and a 3,000W inverter/charger can cost $10k+.
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Current vs. Capacity: Understanding Amps and Amp-Hours in Your Van Electrical System
Amps vs Amp-hours. Current vs capacity. A classic rivalry! No. Wait. How can we pit these two important parameters against each other when they’re complementary? This blog revisits some important subtopics on sizing your electrical system, with a focus on how much current (Amperes, or Amps) and storage capacity (Amp-hours, or Ah) your system may need. Why is there a 250 Amp fuse on my 300 Ah battery? You’re selling a 460 Ah battery, so do I need more than one battery in my system? What’s with all the 4/0 cables, can’t I use smaller ones? These are some common questions we receive about our example wiring diagrams. Let’s try to clarify current and storage capacity using a few examples with our old friend the free example load calculation Google Sheet. Current Current is the measure of the flow of electricity through a conductor. At a high level, current flowing from your batteries provides the power (which is current times the battery voltage) needed by your loads to operate. There are a few important considerations in determining your system’s current needs (or is that need for current? bad pun). First, what is the maximum current needed by your loads at any given time? This number is likely much higher than the average load consumption that you analyzed. Looking at Example 1 in the load calculation sheet, let’s consider that you come back to your van at the end of the day after a nice, long hike. You turn on the air conditioner (at max for a while to cool things down), turn on some lights, notice that your refrigerator is running to keep things cold, and fill a pot with water to start boiling on the induction cooktop. Did you look at your battery monitor and realize that you’re using around 250 Amps of current (roughly 3000 Watts on your 12 Volt system) for a little while? Perhaps you made a cup of coffee or threw something in the microwave too, and you peaked at nearly 400 Amps of current! This usage is actually typical, and we should plan for it. Because our vans are our homes, no one wants the power to go out while enjoying our vans. Second, the maximum load current above leads to another consideration of your system’s need for current: the battery specifications. As an example looking at our SOK 314 Ah batteries, the manufacturer recommends a continuous current of 150 Amps charging and 200 Amps discharging. Exceeding these continuous values can degrade your batteries’ long term performance. Given the significant investment in your batteries, this is one of the reasons we suggest multiple batteries in parallel when designing a system. Each additional battery reduces the discharging demand from the other batteries, maximizing short-term and long-term battery performance. Stated differently, batteries in parallel increases the current capability of your system. In this example with SOK 314 Ah batteries, two batteries safely supports 400 Amps continuous discharging as compared to 200 Amps from a single battery. As a result of considering current, we typically recommend three (but at least two) batteries in the scenario above. Capacity Capacity is a little more straightforward to consider, and capacity is well-covered in our sizing your electrical system blog. Capacity is how long can your system sustain your current consumption (Amps multiplied by time) and that’s typically best to consider using the average consumption calculations laid out in our free example load calculation Google Sheet. Capacity is additive, so each battery adds to the total available capacity in your system. Again returning to Example 1, now let’s consider that you plan to boondock for four nights. No shore power. No driving. While solar is great when you have it, you decide how certain you are to predict sunny skies during the day, and that assumes that you don’t park in the shade anyways. (Spoiler alert, on my trips it rains anyhow!) If you maintain the average consumption of around 250 Ah a day for four nights, you’ll want more than four times that capacity in your battery bank. Don’t forget another important battery specification, the manufacturer’s recommended depth of discharge, which is typically 80% to maintain good performance over the life of your battery. In our capacity example, we would recommend at least four SOK 314 Ah batteries (or at least three Epoch 460 Ah batteries) to meet your boondocking goals. Wrap-up Also necessary in your considerations is design margin, or some additional comfort zone if your usage predictions are off. Maybe you use the van differently than you projected, or what if you decide to add another gadget to better enjoy your van? You don’t want to plan your system right at the edge of manufacturer specifications. On top of that, there’s Physics to deal with…current increases as battery voltage decreases (which is during discharging), some loads have inrush or starting currents even higher than typical consumption, and efficiency decreases with increased heat. Design margin, as well manufacturer recommendations, are additional reasons that multiple, paralleled batteries are best suited for most van applications to address both current and capacity. Let’s wrap up by revisiting the three common questions above with our Amps vs Amp-hours knowledge. Why is there a 250 Amp fuse on my 300 Ah battery? We’re back to Amps vs Amp-hours confusion, aren’t we? Your maximum load calculations, spread across multiple parallel batteries, help determine the expected maximum current from each battery. Fuses are specified to protect the cables, and the cables are specified for the maximum expected current plus margin. It’s perfectly normal for a 300 Ah battery (for example, with specifications for 200 A continuous and 400 A peak current discharging) to be fused at 250 A. You’re selling a 460 Ah battery, so do I need more than one battery in my system? Maybe you’re building out a minimalist van, and your load calculations suggest some combination of low current or low duration meets your needs. Or maybe you’re always plugged in to shore power. In those cases, yes one battery may be perfect. For many of our customers, off-grid capabilities combined with daily van needs like cooking or cooling will lead to different conclusions. That’s why our example diagrams and recommendations typically reflect systems with 2-4 batteries in parallel. What’s with all the 4/0 cables, can’t I use smaller ones? This topic is related to current and fuse selection, but it comes up often enough to touch on in this blog. As you can see on this handy wire gauge calculator, maximum current is only one of the factors in properly designing your cables. You can use smaller diameter cables, if your fusing and current consumption is reduced, among other things. One way to reduce large diameter cables is using multiple batteries in parallel such that each battery contributes less current (through appropriately reduced fuse sizes). Another way to reduce cabling size is to increase system voltage (to 48 Volt or 24 Volt). Quadrupling the voltage reduces current by a factor of four, and the lower current reduces cable losses…because Physics. Reducing current allows significantly smaller cables to be specified (again, with appropriately reduced fuse sizes). Current? Or capacity? With modern advances in battery technology, vanlifers are the winners on both counts!
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DIY Camper Van 24V Electrical System
Example DIY Camper Van 24V Electrical System (Internal BMS batteries) Jump To Example Wiring Diagram Product Bundle For This System In this post we’re going to discuss a popular topic these days – 24 Volt electrical systems. This system offers some benefits compared to the traditional 12 Volt electrical system detailed in our original camper van blog post. This post includes a detailed wiring diagram and system bundle needed to put together a very reliable and robust electrical system for your camper van that is capable of extended off-grid adventures and powering just about anything you throw at it…including more efficient use of those power-hungry rooftop air conditioners. What’s different? Well the battery bank is 24 Volts instead of 12 Volts, obviously. Except the system has 12 Volts too. Let’s un-confuse things. Looking at the 24 Volt example wiring diagram as compared to the 12 Volt example wiring diagram, all of the key features and components are quite similar between the two systems. There’s still a Victron Multiplus inverter/charger, one or more DC-DC (alternator-based) chargers, solar capability, an optional Victron Cerbo communication center, the ability to use shore power, and a load center for AC & DC. Victron, other battery manufacturers, air conditioner companies, and large segments of the camper van and marine industries have long supported 24 Volt equipment. While the 24 V system looks quite familiar, each equipment model has been carefully selected for compatibility with a 24 Volt house (domestic) battery system. So why is there still 12 Volts then? Because some popular equipment in our vans still only operates on 12 Volts. We’re looking at you MaxxFan (at the moment, anyways). But we’ll explain shortly why this additional wrinkle is not hard to overcome, and more importantly why considering a 24 Volt system may be a better choice for some vanlifers. Also different in this 24 Volt system is a new product from Victron, the Orion XS 1400 DC-DC charger. The XS 1400 operates in 12 or 24 Volt systems, can charge up to 50 Amps, and supports parallel operation like existing Orion XS chargers. Why is 24 Volts better? Efficiency is the name of the game for a 24 Volt system. Higher voltage systems are well suited for large DC loads like rooftop air conditioners. On our website we’ve already shown how much more efficient DC air conditioners can be over traditional AC air conditions. But take a closer look at the specifications on some of our air conditioners or the comparison spreadsheet. In particular, let’s look at air conditioner capacity in BTUs versus power consumption. The Nomadic Cooling X3 offers a great example, where the 24 V X3 and 12 V X3 have the same rated power consumption, yet the 24 V model has a rated cooling capacity that is 12% higher! Why? Because the air conditioner operates more efficiently at the higher operating voltage. Other air conditioner brands and models show similar efficiency benefits. Since an air conditioner may be the single largest, sustained load for an off-grid camper van, improvements in efficiency are a big deal for maximizing your battery capacity. While some van products don’t run on 24 Volts yet, and we’ll get back to those, you will find that a majority of your DC system can operate natively at 24 Volts. Of course this includes your Victron components like the Cerbo and chargers, but you can also find refrigerators, water pumps, LED lighting, fans, and host of other equipment working at 24 Volts. While we’re harping on efficiency, let’s not miss out on a chance to consider a little Physics. By increasing the house voltage to 24 Volts over 12 Volts, the required current is reduced by 1/2. Resistive losses in your cabling (commonly referred to as I2R losses), have been reduced significantly (almost by 1/4, due to the I2 factor). Note that we say almost 1/4, because with the reduced current you’re likely to use smaller cable gauges for lower cost and easier wiring. Smaller cable gauges do have higher resistance per foot, however not by a factor of 2 given the range of cables we’re using. So reduce by 4, increase by less than 2, blah blah blah…using 24 Volts gives you less losses (greater efficiency) and smaller cables. That’s a win. Better equipment performance and less cable losses with smaller/cheaper cables, those are the main reasons why a 24 Volt system may be the right choice to maximize your battery capacity and improve your off-grid experience. Things to consider: So why are we not talking about a 48 Volt system here? Good question. And maybe we will be. 48 Volt air conditioner performance and efficiency is a great reason to consider a 48 Volt system over 12 Volts (and 24 Volts). However, many of the other camper van items (like refrigerators, possibly the second highest power consumer in most systems) are not readily available at 48 Volts. For now, we’ve found that 24 Volts offers a significant improvement with a majority of the system running at the house voltage, avoiding having to turn around and run most of the equipment at 12 Volts anyways. Included in this system is a Victron Orion 24/12 Volt converter. With as many loads as possible running natively on 24 Volts, the 70 Amp 24/12 converter is more than sufficient for most customer’s needs. You need to be mindful that there is now a 24 Volt distribution center (using one or more Lynx distributors as shown in the example wiring diagram) as well as a 12 Volt distribution center (shown using our favorite WFCO combined AC/DC load center). For this system, we think that the improvements in performance offset the small increase in components required to use both 24 Volt and 12 Volt equipment simultaneously. Solar charging is readily supported on a 24 Volt system, and most Victron MPPT chargers automatically select the house voltage. Because the MPPT chargers require a PV voltage higher than the house battery voltage to initiate a charge cycle, solar selection is a tiny bit (and we really do think it’s tiny) harder to select. Most customers can use two or more solar panels (typically in series), and there are 24 Volt solar panel options out there, like this one from Newpowa, where customers using only a single panel or desiring a parallel panel configuration can still effectively utilize solar. 48 Volt solar charging is a little more limited in this case, primarily because rooftop DC air conditioners necessarily compete with space for enough panels. There are not a lot of options for 48 Volt panels that fit on camper van rooftops, so multiple 24 Volt panels in series are typically needed. While solar charging for a 48 Volt house system is possible, it’s another minor reason why a 24 Volt system may be a good compromise right now. Wiring Diagram Our example wiring diagram shows Epoch 24V 230Ah V2 Elite Series batteries. These are excellent value batteries supporting communications to a Victron GX Device (such as a Cerbo GX) for advanced monitoring and charging using DVCC (cables included). The Elite Series batteries include internal heaters. A system with just two of these batteries provides 12,000 Watt-hours of power capacity, which is a great starting point for your off-grid adventures. While we think the Epoch batteries are a great choice, this system bundle could operate with any 24 Volt Bring-Your-Own internal BMS battery from SOK or other reputable manufacturers. 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 24V Internal BMS Wiring Diagram for our example wiring corresponding with this blog post. Tips If you Bring-Your-Own-Battery, programming your system at 24 Volts will be similar to the steps we’ve shown with our 12 Volt internal BMS system. Programming examples include the Multiplus and Cerbo GX configuration, where you’d carefully replace 12 Volt specifications with appropriate parameters from your 24 Volt battery manufacturer. If you select the Epoch Elite batteries as part of bundle, the batteries include a cable for connecting the batteries to a Cerbo GX. Most customers will want to take advantage of these features, using the following steps as part of the installation: Set the battery DIP switches per the manual, representing the battery configuration and total capacity of the battery bank in your system. Install the communications cables per the battery manual, specifically making sure that the INV-labeled end of the Victron cable is connected to the Cerbo GX. Daisy chaining of multiple Epoch batteries is done with the CAN-labeled cable. Terminators are not required. Taking note of which VE.CAN port on the Cerbo you’re connected to, ensure that the CAN profile is correctly set: Console(Remote Console) > Settings > Services > VE.Can port # > CAN-bus profile > (select the CAN-bus BMS LV (500kbit/s) setting) Assign the Cerbo to use the Epoch BMS as the battery monitor (see note below): Settings > System Setup > Battery Monitor > select (Epoch BMS name) on CAN-bus. Alternatively, if you installed a Victron shunt, you would select that shunt as the battery monitor. Configure DVCC. When using the DVCC, you need to assign Epoch as the controlling BMS on the Cerbo: Settings > DVCC > Controlling BMS > select (Epoch BMS name). NOTE: The Epoch batteries will aggregate multiple batteries into one battery BMS/shunt to be displayed & utilized by the Cerbo GX. An additional system shunt is not required, but through testing, we have discovered that the internal BMS will not register current below 1 Amp. There will be a SOC drift of unregistered current resulting in an actual SOC that is lower than the reported SOC. The solution is to install a Victron shunt and to use that as the battery monitor yet still use the Epoch BMS as the controlling BMS in the DVCC settings. Epoch is aware of this issue and have stated that they are working on the issue.
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Overview and Demonstration of Victron Energy DVCC
DVCC (Distributed Voltage and Current Control) is an awesome feature of Victron Energy power systems that intelligently coordinates charging your battery bank with multiple charging sources if you have Victron chargers and a GX device such as a Cerbo GX. This video dives into what it is and how it works! Shopping for a power system and want the best technical support in the industry? We’re a stocking distributor that ships fast and free and have your back when you have questions! Resources mentioned in the video: 1) Using a SmartShunt as a “DC Meter” 2) Wakespeed WS500 Alternator Regulator DVCC Information 3) Requirements for using DVCC 4) DVCC compatible batteries tested by Victron Energy
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Deep Dive - Wakespeed WS500 Wiring Harness Video
If you’re confused about all the connections on the Wakespeed WS500 alternator regulator wiring harness this video will detail each leg and connection for you. Want to nerd out some more about the Wakespeed? Check out this other deep dive with one of the creators. You might be interested in our best price secondary alternator electrical system kits that include everything you need at an awesome price with our world-class support. Check out the blog posts below that also link to an example wiring diagram and the product bundles! 12-Volt Secondary Alternator Camper Van Electrical System Kit 48-Volt Secondary Alternator Camper Van Electrical System Kit
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