Wiring
How to Wire a Campervan Electrical System
Wiring a van for the first time feels intimidating, but the layout is logical: a battery in the middle, charging sources feeding in on one side, and your loads drawing out the other. This walkthrough explains each part and how it connects, in beginner-friendly language.
The mental model: power flows through the battery
Everything in a van system connects to the battery, but not directly. Charging sources (solar, the alternator) push power in, and loads (lights, fridge, inverter) pull power out. Between them sit two simple hubs called bus bars, one positive and one negative, plus fuses to protect every wire. Get that picture and the rest is just connecting parts in the right order.
The parts, from battery outward
1. The battery
A 12V LiFePO4 battery is the standard for vans. It is the bank that stores all your energy. Mount it securely so it cannot move while driving, and keep the terminals accessible.
2. Main fuse and battery shutoff
Right at the positive battery terminal, install a main fuse (often a Class T or ANL fuse) and a battery disconnect switch. The fuse protects the main cable, and the switch lets you kill all power for service or storage. This is your most important safety hardware.
3. Positive and negative bus bars
Run one heavy cable from the battery positive (through the main fuse) to a positive bus bar, and one from the battery negative to a negative bus bar. Now every other part connects to the bus bars instead of fighting for room on the battery terminals.
4. The charging sources
Two common ways to refill the battery:
- Solar: panels on the roof feed a charge controller (MPPT is standard), and the controller feeds the bus bars. Never wire panels straight to the battery. See our charge controllers guide.
- Alternator (DC-DC charger): a DC-DC charger takes power from the engine's starter battery while you drive and safely charges your house battery. It is the fastest way to refill on travel days.
5. The loads
Two kinds of loads pull from the bus bars:
- DC loads (lights, fridge, fans, USB, water pump) connect through a fused distribution block. Each circuit gets its own fuse sized to its wire.
- AC loads (laptop charger, blender, anything with a wall plug) run from an inverter, which converts battery DC into household AC. Choose pure sine wave.
The order to build it
- Mount the battery, main fuse, disconnect switch, and both bus bars. Leave the battery disconnected.
- Add the charge controller and wire it between panels and bus bars (panels last).
- Add the DC-DC charger if you are using alternator charging.
- Add the DC fuse block and wire your 12V loads, each on its own fuse.
- Add the inverter on its own heavy, fused cable to the bus bars.
- Double-check every fuse and connection, then connect the battery last.
Building in this order means the system is never live while you are still adding parts, which is far safer.
Recommended gear
The simplest way to avoid mismatched parts is to follow a proven parts list. Our Classic 400W RV and van build lists every component, the battery, MPPT controller, DC-DC charger, inverter, and a wiring kit, in compatible sizes, plus a wiring diagram. For a smaller rig, see the minimalist van build, and to tailor it to your van use the System Builder.
The two hero parts beginners buy first are the battery and the inverter:
Check Van Battery Price on Amazon Check Pure Sine Inverter Price on Amazon
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Frequently Asked Questions
What order do I wire a campervan electrical system?
Build the battery and safety hardware first (battery, main fuse, bus bars, shutoff). Then add the charging sources (solar via the controller, and a DC-DC charger from the alternator). Then add the loads (a fuse block for DC devices and the inverter for AC). Connect the battery last, after everything else is in place.
Do I really need fuses everywhere?
Yes. A fuse protects the wire, not the device. Without one, a short can turn a battery cable into a fire starter in seconds. Every wire leaving the battery needs a fuse close to the battery, sized to the wire.
What are bus bars and why use them?
A bus bar is a single metal bar with several connection points. Instead of cramming many wires onto the battery terminals, you run one big cable to a positive bus bar and one to a negative bus bar, then connect everything else there. It is tidier, safer, and easier to service.
Can I wire 120V outlets in my van myself?
For low-voltage 12V DC work, careful beginners can do a lot themselves. But permanent 120V or 240V AC wiring, especially shore-power hookups, is where mistakes are dangerous and often must meet code. Have a licensed electrician handle or inspect that part.