DIY Camper Van Electrical System Example (Internal BMS Batteries)

Example DIY Camper Van Electrical System

This post was originally published in September 2020 and is great for a system up to about 300-400 amp hours of battery storage.

This post includes a detailed wiring diagram and complete list of materials 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.

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Overwhelmed? You’re not alone! Electrical systems can be extremely confusing. That’s why we've gone into so much detail in this post. I’ve worked with many DIY van builders who, understandably, can’t wrap their head around their electrical system. However, most of the time, once they purchase all the components and start to lay it out it starts to come together for them. So, I recommend you do the same. Get all the materials, decide where you’re going to install your system and measure that area. Then tape out a section of a table or counter top and start putting the various components together into that space. This will help you get an idea of where each device should be located and everything will likely start to make more sense. Then you can use either tape or string to start “virtually” hooking things up. Some people use various colors of electrical tape to represent various wire gauges. Going through this exercise will help you plan your install and understand how everything works together!

If you want to learn more about how electricity works and take a deep dive, I recommend a free PDF book published by Victron called Wiring Unlimited.

Contact us for more information or to get something scheduled!


  • 400 amp hours of lithium battery storage with built-in BMS
  • 400 watts of rooftop solar
  • 2400 watt inverter (up to 6000 watts surge) with 120 amp shore power charging capacity
  • Integrated 12 volt DC and 120 volt AC load center
  • 60 amps of alternator charging when driving/engine is running
  • Optional pre-inverter shore power outlets
  • Battery monitoring with Bluetooth

It’s super important to realize that there are hundreds of ways of skinning this cat. How awful. We won’t be skinning cats and neither should you. Anyway, the point is that this information should be considered a guide not gospel. You certainly could build out this system exactly as detailed but I would recommend considering your particular needs and then adjusting accordingly.

Also, wire lengths matter. This electrical diagram assumes that there is about a 20′ run from the vehicle battery back to the driver side wheel well where the “primary” electrical system is installed. What I mean by “primary” is most of the stuff you see on the wiring diagram – all the main parts but not the “branch circuits” that power the actual loads in the van like lights and fans, etc. It also assumes all those components are close together – not more than 5 (ish) feet of cable run between them. If your actual setup is different than this you need to adjust the wire gauge (AWG) accordingly. The Blue Sea Circuit Wizard is a great tool for understanding what gauge wire you need. You put in the load in amps, the length of the cable run and how long it will be running in minutes and it will tell you the correct gauge. I favor “over gauging” in general. Wire is pretty inexpensive relative to the other parts. In this wiring diagram I have also over gauged to keep it a bit more simple so that you don’t need so many types/gauges of wires and lugs and so on.

Speaking of wiring… you’ll probably use wire loom to protect your wires when you run them in areas they might be damaged by rubbing against stuff. So, let me introduce you to this “wire loom insertion tool“. It’s pretty much a game changer.

Why A 50 Amp Breaker?!

With most 2000 or 3000 watt inverters you would match the shore power’s 30 amp inlet on the output side. However, Victron Multiplus inverters have a unique feature -they will actually supplement the utility power coming in from the shore power plug with their inverted power – up to 3000 additional watts. So, if you manage to have enough stuff running in your van to exceed the 30 amp service from the shore power, the inverter would actually fill in the gap instead of tripping the shore power breaker. So, while this is not likely to happen unless you’re running some kind of crazy loads in your rig, it’s important to provide circuit protection and adequate wiring “just in case”. Therefore this wiring diagram calls for a 50 amp breaker downstream from the inverter with 6 AWG wire instead of a more “typical” 30 amp breaker with 10 AWG wire.

Inverter Wattage

If you look closely at the specs of the Victron Multiplus inverters they don’t actually support continuous 2000 or 3000 watts respectively. This isn’t important but it can be a bit confusing because of how they’re named.

The MultiPlus 12/3000/120 outputs 2400 watt continuous output at 77 degrees, 2200 watts at 104 degrees and surge up to 6000 watts.

The MultiPlus 12/2000/80 outputs 1600 watt continuous output at 77 degrees, 1450 watts at 104 degrees and surges up to 4000 watts.

Victron MultiPlus Inverter/Charger Configuation

Once you get your system all wired up you’ll need to configure/program the MultiPlus to, at minimum, work with the batteries you’ve chosen and maybe tweak a few of the other settings. We have another post on how to do that.

A Little Battery Update (June 2021)
In addition to the complexity, the other pain point around electrical systems is how expensive they are. In particular, the leading brands of lithium batteries such as the Victron SuperPack batteries we show in our example and other popular brands like Battleborn) are very expensive – about $1,000 per 100 amp hours. It’s a classic sort of “pay for what you get” scenario and there are good reasons to purchase the highest quality components. For example, the are excellent quality, designed to last for many years with 10 year (!) warranties. But, the truth is that not every van build needs the very best batteries and there are well-made alternatives that are just about half the price! In some cases, having more capacity (amp hours of stored energy) may be better than more longevity. You can ask yourself, do I want to run the stuff in my van twice as long for a few years or half as long for a decade?

Anyway, Will Prowse made an excellent video testing out well-built but lower cost lithium batteries that is worth checking out. One example is the SOK 206 amp hour battery that is currently selling on Amazon for $1,029.

Wiring Diagrams

The image below is for quick reference but I recommending downloading the PDF file (below) for much more detail and the ability to print/zoom in.

If you have AC loads that should ONLY be powered by shore (utility) power, (not inverted AC power), you can use the “AC out 2” connections on the MultiPlus inverter/charger which is only “live” when shore power is available. One good example of this would be an AC/DC refrigerator. Many of those will “default” to AC power when it’s available. If you wired up an outlet near your refrigerator that was powered by the inverter, the fridge would switch to that source of power anytime the inverter was on (inverting) which is less energy efficient that it continuing to run off the 12 volt DC power. If, instead you wire up that AC outlet that feeds the refrigerator, it will only run off the AC power when you have shore/utility power.

Item Cost Quantity Total Notes
If you are planning on using Victron Energy components like we show in this example, you should check out our discounted Victron bundle. We can pass on a lot of savings to you if you buy many of these items from us!

You can check out this simplified (print-friendly) version of the parts list where we’ve indicated what is available

Battery Bank
Victron 100 amp hour SuperPack lithium battery $1,025.00 4 $4,100.00 This system shows 4x, 100 amp hour batteries from Victron. This can be expanded as needed. Whatever batteries you use, be sure to check out the specifications to be sure that the maximum continuous discharge rating will support your loads. You can read the Victron SuperPack specifications in this PDF. This system is designed for a maximum of 400 amps coming from the battery bank at any one time. The maximum continuous discharge on the “high current” 100 amp hour SuperPack battery is 100 amps which is one reason we show 4x of these batteries in the example.

By the way, not everyone needs the very best batteries. See my “battery update” above. If you’re on a budget or not going to be traveling in your van for a super long time, you might consider something like the SOK 206 amp hour battery that is about half the price of a Victron. Here’s another lower cost battery with good reviews. I never used either of these batteries – just giving you some food for thought!

Blue Sea 300 amp battery switch $28.00 1 $28.00 This will serve as the main disconnect between your battery bank and all the DC loads so you can turn the system off when needed. You want the one that is labeled “on, off w/ knob”.
Victron Energy Mega Fuse Holder $15.00 1 $15.00 This will hold the fuse that protects the wiring between your battery bank and the Lynx distributor.
400 amp mega fuse $15.00 1 $30.00 This fuse will go into the fuse holder (above). You should consider having a spare!
Victron Energy battery monitor with Bluetooth BMV-712 $205.00 1 $205.00 The BMV-712 allows you to monitor all the energy (current) being consumed by things in the van or energy (current) being generated from solar or other charging methods. You can see this in both amps or watts and also monitor the the voltage of your battery bank. In addition, the unit also has a sophisticated algorithm to display the state of charge of your battery bank in both percentage of capacity remaining and remaining amp hours. Using the Bluetooth connectivity and the Victron app, the you can log historical data including energy use, battery efficiency, deepest discharge, number of charge cycles and more.
Victron Energy MultiPlus 3000 watt inverter/charger with remote control $1,425.00 1 $1,425.00 The inverter will either pass through utility (shore) power when available or “invert” your battery bank’s 12 volt DC power to 120 volt AC power which is what you’re used to in a home for things that need that type of power such as electronics, water heaters, microwaves, etc. It also has a “charging” function that will take utility (shore) power and charge your battery bank with that energy – up to 120 amps. 2400 watt continuous output at 77 degrees, 2200 watts at 104 degrees, surge up to 6000 watts
Victron MK3-USB Interface $61 1 $61 This little device allows you to connect the VE.Bus on your Victron MultiPlus inverter/charger to a computer using USB and then configure/program the unit with VictronConnect software. Here’s a post all about that process if you’re interested.
400 amp mega fuse $11.00 1 $11.00 This fuse will connect across the 1st position on the Lynx controller for circuit protection between the positive bus and the inverter DC input
Alternator Charging – DC-DC Charger
Victron Orion 30 amp DC-DC Charger (non-isolated) $228.00 2 $456.00 These devices connect to your van’s battery to charge your house battery bank when you’re engine is running. The Orion units max out at 30 amps so we suggest running two in parallel for a combined charging current of 60 amps which is high enough to help you charge quickly but not enough to damage a typical van’s factory alternator.
Littelfuse 04980933.X Midi Fuse Holder $35.00 2 $70.00 We show these handy boxes being used to combine the inputs and outputs from the two Orion DC-DC chargers while adding circuit protection (fuses). Here’s a photo of the configuration.
2-pack, 40 amp MIDI fuses $17.00 2 $40.00 These fuses are used in the Littlefuse boxes above.
Distribution/Load Centers
WFCO WF-8930/50NPB-50 50 amp (or 30 amp) AD/DC load center $89.00 1 $89.00 Simplifies design and saves space by combining both 12 volt DC and 120 volt AC circuits into one load center/power distribution panel.

Good video on how to wire this up here.

Square D 50 amp HOM type single pole circuit breaker $12.00 1 $12.00 Main breaker for AC distribution.
Square D 15 amp HOM type single pole circuit breaker $5.00 3 $15.00 You’ll want one of these for each 120 volt AC branch circuits. I’ve indicated 3x here but you may need more.
Victron Energy Lynx Distributor (DC) $205.00 1 $205.00 This product is pretty neato. It really cleans up your wiring since it serves as a 1) positive bus bar 2) negative bus bar and 3) 4x fuse holders. So, it combines a lot of things into one box that you would normally need additional wiring and components for. And, if you consider not needing to purchase all those things, it’s a great value too.

Note about LED lights: often this Lynx Distributor is paired up with the Lynx Shunt or a Victron BMS. But, those are not needed if you use the BMV-712 battery monitor I’ve listed here that has its own shunt for monitoring. Those devices are what normally powers the Lynx Distributor’s fancy LED lights that indicate if each of the circuits are working (fuse not blown). However there is a way to do this (hack?) without the devices which I detail toward the bottom of this post. Click here to jump down to that section.

80 amp mega fuse $8.00 4 $32.00 1x fuse will connect across the 2nd position on the Lynx controller for circuit protection between the positive bus and the load center DC input.

1x fuse will connect across the 3rd position on the Lynx controller for circuit protection between the solar controller output and this positive bus on the Lynx.

1x fuse will connect across the 4th position on the Lynx controller for circuit protection between the DC-DC battery charger output and the positive bus.

1x fuse goes between the vehicle battery positive terminal and the positive cable run from the vehicle battery to the DC-DC charger DC input.

Solar System
Renogy 200 watt (12 volt) monocrystalline solar panel $300.00 2 $600.00 These are quite wide (24.1V, 63.8 x 25.9 x 1.4 inches). You may decide you prefer a smaller panel with slightly reduced output if they don’t fit up on your rig’s roof. Since I like to have air conditioning and vent fans/etc. up on my van roof, I wanted a total of 2x panels but if you have more space, there are certainly more options!
Weatherproof solar cables entry gland $12.00 1 $12.00 After you drill a hole in our roof, this can cover that up and the cables from your solar panels can go through this down into the van. There are two entry glands – one for your positive and the other for the negative.
Victron Energy SmartSolar MPPT 50 amp charge controller 100/50 $228.00 1 $228.00 The charge controller takes the raw power from your solar panels (around 48 volts and 9 amps in this case) and converts it to the correct charging voltage and current for 3-stage charging of your battery bank.
2-pole, solar disconnect switch (32 amp) $22.00 1 $22.00 This breaker/disconnect is wired between the solar panel wire coming down from the roof and the solar panel (PV) input on your charge controller. This allows you to disconnect both the positive and negative current flow and essentially “turn off” your solar panel’s output.
DIN rail breaker enclosure box $20.00 1 $20.00 This DIN railing enclosure is where the solar disconnect switch is installed.
Renogy solar panel mounting brackets (2 sets of 2x) $20.00 1 $20.00 These “z-brackets” will mount your solar panels to your roof. I recommend using plus nuts and then covering the entire bracket with Dicor sealant.
Shore Power
Furrion 30 amp shore power inlet $60.00 1 $60.00 This is normally installed on the outside of the van on one of the side walls. Some people prefer to hide it more by installing onto a box below the bumper.
Blue Sea 8077, 30 amp shore power breaker $102.00 1 $102.00 This breaker is intended to protect your wiring from the shore power inlet to the inverter/charger. Some installers rely on the circuit protection provided by the outlet you’re connected to and do not install this.
25′, 30 amp shore power cable $55.00 1 $55.00 Used to hook up to shore power from a campground/home 30 amp plug.
15 amp to 30 amp adapter $10.00 1 $10.00 You can use this adapter to use your shore power cable with a standard, 15 amp outlet.
Wire + Lugs + Heat Shrink + Connectors
10′ red and black (20′ total) 4/0 AWG cable $90.00 1 $90.00 This heavy duty cable will be used to connect your battery bank to the Lynx DC distributor (through a main cut-off switch on the positive side). It will also be used to connect the between the Lynx Distributor to the inverter. This allows for up to 5 feet of cable for each of these runs on both the positive and negative side.
20′ red 2 AWG cable $38.00 1 $38.00 Cable run from vehicle battery to DC-DC charger (positive).
15′ red 6 AWG cable $20.00 1 $20.00 Used for the following DC positive runs:
Approximately 5′ – used between the output of the solar charge controller and the positive bus (Lynx controller).
Approximately 5′ – used between the output of the DC-DC charger and the positive bus (Lynx controller).
Approximately 5′ – used between the positive bus (Lynx controller) and the DC input on the load center.
10′, red and black 10 AWG solar extension wires with one male and one female MC4 connectors $19.00 1 $19.00 These cables will be used to connect your solar panels down through the entry gland to your solar charge controller. They come with the “matching” MC4 connectors you’ll need up on the roof and bare wire on the other side where they will connect to the solar disconnect switch. Then you’ll need a little bit more 10 AWG to go between the output of that disconnect switch to the PV inputs on the solar controller itself.
10/3 stranded copper cable (3x 10 AWG wires inside an insulated jacket) $2.00 10 $20.00 This cable will be used to connect the shore power inlet to the pre-inverter load center (if used) and from the load side of the main 30 amp breaker in this panel to the inverter input power connections. If you don’t use the pre-inverter load center you won’t need as much cable and it will go directly from the shore power inlet to the inverter input power connections.
6/3 cable (3x 6 AWG wires inside an insulated jacket) $65.00 1 $65.00 From the inverter’s output to the AC/DC load center’s AC main breaker. This carries the 120 volt AC power from the inverter (and via shore power through the inverter) to your load center and all the downstream AC circuits.
25′ of black and red 16 AWG cable $8.00 1 $8.00 I would recommend using the red wire for the ignition trigger wire from the “upfitter connection” on the passenger side “b-pillar” back to the location of the DC-DC charger. Whatever remains can be used in various places on your build including low draw DC circuits such as lights, etc.
10-pack, 4/0 AWG 5/16″ lugs $21.00 1 $21.00 These lugs will be crimped onto the 4/0 AWG wire used between the battery bank and the Lynx distributor and to the inverter.
10-pack, 4/0 AWG 3/8″ lugs $21.00 1 $21.00 These lugs will be crimped onto the 4/0 AWG wire used in places where you need the larger 3/8″ lug.
25-pack, 4 AWG 5/16″ lugs $15.00 1 $15.00 These lugs will be crimped onto the 6 AWG wire used throughout the system.You’ll need about 12 but extras are helpful!
15-pack, 2/0 AWG 5/16″ lugs $22.00 1 $22.00 These lugs will be crimped onto the 2/0 AWG wire that connects each battery together. You’ll have a few extra which is handy.
25-pack, 6 AWG 5/16″ lugs $15.00 1 $15.00 These lugs will be crimped onto the 6 AWG wire used throughout the system. You’ll need about 12 but extras are helpful!
10-pack, 2 AWG 5/16″ lugs $13.00 1 $13.00 These lugs will be crimped onto the 2 AWG wire used for the connection between the vehicle battery and the DC-DC charger.
10-pack, 6 AWG #10 lugs $12.00 1 $12.00 These lugs will be crimped onto the 6 AWG wire used for the connections between the Orion 30 amp DC-DC chargers and the Littelfuse fuse holder. The Littelfuse has #10 size studs.
Black 3/4″ heat shrink (4′ length) $8.00 1 $8.00 Heat shrink for 2/0 AWG cables and 2 AWG cables
Red, 3/4″ heat shrink (4′ length) $8.00 1 $8.00 Heat shrink for 2/0 AWG cables and 2 AWG cables
Black 1/2″ heat shrink (4′ length) $6.00 1 $6.00 Heat shrink for 6 AWG cables
Red 1/2″ heat shrink (4′ length) $1.00 1 $1.00 Heat shrink for 6 AWG cables
Various heat-shrink, crimp-on spade connectors $22.00 1 $22.00 The positive wires for 12 volt DC branch circuits to things like lighting/refrigerator/etc. will connect to the load center using these spade connectors. This kit includes common sizes for wires you’ll likely use for this.
Various blade fuses $9.00 1 $9.00 This variety kit of blade fuses is a simple way to have a range of capacity for fuses you’ll need for the 12 volt DC load center branch circuits.
1/4″ thick x 1″ tall x 6″ long copper flat bar $18.00 1 $18.00 You’ll cut short sections of this flat bar to use instead of a wire. In some cases, where your connections are very close together – such as the connection between the 300 amp battery switch and the Lynx distributor, it’s easier and cleaner to use straight copper. 1/4″ thick by 1″ tall flat bar is roughly the same conductive equivalent as 4/0 wire which you could use instead of this. Once you cut the copper bar to length you can drill appropriately sized holes and use 5/16″ bolts with washers and nuts to tighten down the connections.

Another option is these Blue Sea ML Series Link Bus connectors (9160) that can handle 500 amps of current.

Blue Sea 30 amp AC shore power main breaker (8077) $95.00 1 $95.00 This main breaker is wired between your shore power inlet and your inverter/charger AC input. Some installers will forgo this and hope/assume that the shore power they are connecting to is protected/wired correctly.
10′ of red and black 10 AWG cable $16.00 1 $16.00

Note: pricing changes often and we don’t update the prices.

If You’re Using a Renogy DC-DC Charger Instead of the Victron Orion Units

Unlike some other battery-to-battery charging products that sense voltage and trigger the charging based on that, the Renogy DC to DC charger (or battery-to-battery charger) that I used requires you to connect up a 12 volt positive “signal wire” from the vehicle’s ignition switch so that it only charges from the van (vehicle) battery when the ignition is turned on. Without this ignition trigger on this unit or the voltage sensing on others, the battery-to-battery charger could easily drain the van battery since the battery-to-battery charger would be pulling current without the alternator providing a charge.

After some research I discovered that some Promaster vans (2016 or newer I think) have a “Upfitter Connector” on the passenger side “pillar” which is that area just behind the passenger seat where the seat belt connects to the van wall. If you remove the black plastic trim at the bottom of this “pillar” you’ll see a white multi-pin connector (photo below). This is the “upfitter connection” that provides a variety of connection points for the Promaster in one spot. This PDF file (Promaster Upfitter Connector Diagram PDF) details this connector including what each pin on the connector is/does. Turns out that pin #13 is an “ignition feed” that has 12 volt positive when the ignition switch is on. So, I used this to be the “trigger” for the Renogy DC to DC charger.

Note: if you have an older Promaster that does not have this upfitter connection you can consider splicing into the cab area cigarette lighter wiring as detailed in this post. Another option is to use a “tap a fuse” type splitter on fuse #31 in the Promaster fuse block (below the steering wheel). The photo shows this location. These things allow you to maintain the fusing for the original circuit but tap into that fuse location for a second circuit. In this case you’d use a 5 amp fuse for each.

Close Up Shot of Promaster Van Upfitter Connector with Pin #13 Connected:
Promaster Van Upfitter Connection

In order to do this, I had to order the correct, “male” version of this connector (part number 1-480710-0) as well as the “pin” itself (part number 350218-1).  The way this works is that you solder the correct wire to an empty pin and then insert that pin into the correct position on the connector thus allowing you to access and wire up a variety of things to this upfitter connector. These parts are pretty inexpensive so I bought a few with the expectation that I’d destroy a few figuring out how this all works. I’m glad I did because I did indeed destroy a few experimenting. Ultimately, it’s not difficult but finding the right parts and how they fit together took some time. So hopefully this saves you that time!

Soldering the Wire to the Pin:

The wire coming out of pin #13 on the Upfitter Connector runs back to the rear passenger side wheel well where the primary electrical system is installed and is connected to the Renogy DC to DC charger on a terminal labeled “D+”. Below is a photo of this connection:

Next I had to configure the Renogy DC to DC charger to correctly charge the lithium batteries using the DIP switches pictured above. The manual for this Renogy DC to DC charger is really bad and the section on setting up the DIP switches is complete gibberish. I gave up on it pretty quickly and called into Renogy support. The correct DIP switch settings for charging lithium batteries with the Renogy DC to DC charger is:

  • Switch #1: Off
  • Switch #2: On
  • Switch #3: On
  • Switch #4: On
  • Switch #5: Off

Turning On The LED Lights On The Lynx Distributor

There are LED lights on the Lynx Distributor that indicate if each of the circuits is live (the fuse isn’t blown). They light up green when it’s good and red when it’s not. These lights are normally powered when the Lynx Distributor is paired up with the Victron Lynx Shunt but you don’t need that if you use the “better-for-vanlife” (my opinion) BMV-712 battery monitor (listed above) which has it’s own shunt for monitoring.

So, if you don’t want to buy that hardware but do want the fancy lights, you can “hack” the lights with a 12 volt DC to 5 volt DC converter and an RJ11 “phone style” connector. This will provide the 5 volt power the LED lights need to fire up. Below is an illustration on how you’d do this – at your own risk, of course.

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