12V Van Wiring Diagram - Simplified Guide

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In this video, I'm going to show you how to set up a reliable 12V electrical system for a camper van without breaking the bank. When my friend wanted a budget-friendly electrical system for his camper to travel through Italy, I came up with a solution that meets all his needs without costing a fortune.

We'll cover everything from choosing the components, what the system can run, wiring and fuse sizes, and finally, the total cost. Stick around, and I’ll walk you through each step to make it simple and affordable. Plus, I'll share the 12v van wiring diagram we used to build the system.

Solar: For our project, we could fit up to 400W of solar panels on the roof. We chose four 100W panels wired in parallel. This setup ensures maximum efficiency, even if one panel gets shaded. I'll also explain how to size the charge controller and ensure it can handle the maximum input voltage.

Alternator: We used a battery-to-battery charger to recharge the battery using the van's alternator. This is essential for controlling the current going into the battery, preventing damage to the alternator and wires. I'll discuss the wire and fuse sizes needed for this setup.

Shore Charging: For recharging the battery at a campground, we chose a standard 12V 20A lithium battery charger. This option is perfect for overnight stays.

I'll discuss the battery and inverter sizes required based on daily consumption. My friend made a list of all his devices and their usage times, including a small 12V fridge, laptop, lights, microwave, USB charger, and a 12V water pump. We decided on a 12V 200Ah lithium battery, which is more cost-effective compared to lead-acid batteries.

We also need to size the inverter to handle the surge power from the microwave. I recommended a 2000W Giandel inverter, which is budget-friendly and efficient.

Now, let’s put everything together in a comprehensive 12v camper wiring diagram. I'll explain each step clearly, including the cables, fuses, and breakers we used.

We'll break down how long it takes to recharge the battery using different methods:

- Solar Power: About 1.5 days
- Alternator: 4.5 hours of driving
- Shore Power: 9 hours

[pkl]

Finally someone shows what is really needed. GREAT video. We've gone 3 summers around the US with a propane stove, 2 wet cel Gp31 batteries, 200 w solar, Renogy DCC50s (combination b2b MPPT controller), Isotherm 130 AC/DC Refrigerator with Freezer, 200W cigarette lighter inverter, and a 3g hot water tank with 12V element run the last hour of driving each day. IF we decide we need a toaster or coffee maker we'll add a 2000W Renogy inverter for $280.00. It's not for everyone but if your budget is tight electrics is where to save.

[MatthewYBarbo]

Really love how you explain everything here with such simplicity. The diagrams are easy on the eyes as well. Keep up the great content!

[Ressy]

@6:49 quick correction, 10 gauge is 6mm2 not 4, 4mm2 is 12 gauge, and since most PV's come with 12AWG (4mm2) with only 3-5 feet of cable, your up-to branches will be OK, but after the branch connectors you need the heavier gauge, perhaps this is what you were meaning to say, also you're paralleling, where are the individual in-line fuses?

(Some countries mandate in-line fuses when paralleling - Australia does, fused internally accessible, before combined - when paralleling, used with fuse block method like you show on the battery line does away with branch connectors, simpler too IMHO), I'd also be using another breaker on the MPPT battery out, if for nothing more than use as an isolator, and also a breaker between battery and inverter.

pro tip: when buying MC4's make sure they are the right sizing, average off the shelf are for 12awg/4mm2, you need to make sure the type you buy (using this diagram) is for 10awg/6mm2, or greater if your wire size is bigger, but 10mm2 (8awg) is the biggest you can get in an MC4, also important to note the largest cable dia on all terminals of things like breakers, MPPT, etc, as some MPPTs screw terminals are ridiculously small


Last tip, for wire size, add up all your currents, protection should be 25% greater (as you make mention of calling the safety factor) but what it is also recommended is, the wire size should be 50% greater, eg: 100A = 125A breaker/fuse and 150A capable wire, this way there is no question of electrical wiring being cause for your insurance company denying you payment should your camper/RV/off grid or boat, burn to the ground.

[LeePurtell]

Thanks Nick, I’m very new to this but am following your advice building my very simple camper van 410w setup, see how I go 😂 really appreciate the quality advice.

[stevewhite]

Your the man thank you for helping all of us with questions about solar...

[DaveAppleton]

This was great, I'll be moving onto a narrow boat soon and have to deal with this exact sort of set-up. The problem narrow boats have is finding enough clear space on the roof to fit the amount of panels you would like.

[DarkSevariant]

Informative, Informative, Informative...!! Thank You..!!! 😍😍😍

[kennethwilson]

Very well explained…thank you…Have fun stay safe.

[paolodezar]

So clear and understanding of your formula. !! Just subscribed to your channel great info. Great work!

[adassociates]

In situations when park in the house and connect to power entire house using Transfer switch, what should neutral and ground be separated? Thanks for all your informative videos, you are great👍👍👍👍👍👍

[johnpicone]

Hello, question about your calculation, solar 400 watt X 14.4 Lifepo4 charge current
I noticed in your video, stoped at 3:13, the shor power cable says 14.6.
And my battery manufacture WattCycle also told me to make sure & charge them at 14.6,
So shouldn't we be calculate 400w X 14.6, & not at 14.4?

Im sure there's a good reason for why you do it that way, i just don't understand it yet, is it the bat bms steps it down?

Thank you for all your amazing videos!

[ihabahmed]

ٌYou are a flood of information, thank you, i am still waiting for the 9000 btu Ac backup system.

[leakybean]

I love your content❤ How are the panels made safe by the DC breaker before the charge controller if the panels are still exposed to the sun?

[michaelfitzpatrick]

A few points.
The use of MRBF fuse at the battery is important. Under fault conditions a lithium battery can produce over 7000 amps. Fuses have a limit on how much fault current they can withstand. MRBF can withstand 10000 amps in a 12v system . Alternatives are classT, HRC, and BS88 fuses.
No neutral bond condition or use of RCD protection was discussed with regard to the inverter. Whilst resionably save if a single appliance is directly pluged into the inverter, and distributed AC system with multiple outputs, needs RCD protection.
Any DC or AC system in a RV needs a reference point, the metal body, chassis or frame.
Solar panels in series handle shade better than expected due to bypass diodes . Having 100 watt panels, all In parallel, will perform badly in lowlight conditiond. Having two in series connected in parallel to the other two is series will give a little more power early/late in the day and low light conditions. There is also a lower volt drop due to lower current and easier interconnections.
Well presented video, perhaps using all metric sizes and refering to a conversion chart, would make a clearer presentation.

[wkmaaadventurers]

Very detailed explanation for exactly what I need, thank you very much 👌
Can you send me a diagram for wiring 2 or more batteries instead of 1?

[erroneouscode]

A good design and no criticism intended. But, can I add that in a camping situation though sometimes you don't get the choice to park up where sun is optimal and all those fixed solar panels even when wired in parallel can be rendered useless if you're under trees. I can't speak for other countries typically, but, In Australian bushland that's often a problem when camping. It can be solved by incorporating either a second solar controller to enable 'additional' use of portable solar panels or blankets, Or instead a one or the other two source (position 1 or 2) switch leading to a separate connection socket (Anderson 50A) for portable panels. That way you can switch out the fixed useless shaded panels and still use the existing solar controller for portable panels you can locate out in the sun. Of course it adds to cost but the frustration of getting no sun on your fixed panels will eventually catch you out and make you wish that you had that secondary solar input.

[Fatfreddy]

Good stuff 12v is safer than 48v ime getting 2 x 300ah eve .05 discharge rate, the prices are dropping also new tech storage batteries are on the way soon

[chipcollingwood]

Thanks so much for all this great information. I have a question regarding the shore powered battery charger. Is it safe to have a system where the 3 methods of charging are basically unregulated by a central source. Using a DC/DC charger with MPPT would assure a seamless use of 2 charging inputs. Then using a inverter/charger would satisfy the shore power scenario. Or you could use a separate inverter and ad a stand alone battery charger as you have, but with a disconnect to control the power going to the battery.

[Edward-huzg]

Hello just bought your book haven't started reading yet but my question is can you plug that 14.6 v/ 20 amp lithium charger straight into the ac side of a regular gas generator to charge.

[tex]

Is it possible to work together, charger and solars panels ? Or need to switch off the solar panels when work the charger ?