At home, you plug into the wall and don't think about where the electricity comes from. In a campervan, caravan or motorhome, you're carrying your own power supply, so you need to store it, recharge it, and use it safely.
Two types of power
- 12V DC runs the everyday essentials: lights, water pumps, roof fans, USB sockets, diesel heaters, compressor fridges, control panels. This is the backbone of nearly every van.
- 230V AC is closer to what you have at home: laptop chargers, plug sockets, induction hobs, kettles, microwaves. Not every van needs this. Plenty of simple setups run mostly, or entirely, on 12V.
The leisure battery is the heart of it
The main part of the system is the leisure battery, and it's a different job to your vehicle's starter battery. The starter battery exists to start the engine. The leisure battery exists to power your living area. Keep the two separate, or an evening of lights, fridge and phone chargers can leave you with a van that won't start in the morning.
Battery capacity is measured in amp-hours (Ah). A small weekend van might run on 100Ah wet lead, while a full-time off-grid setup with a fridge, heater and inverter might need 300Ah lithium or more. See the Leisure Batteries guide for how battery type affects how much of that capacity you can actually use.
How does it get charged?
Most systems use one or more of these:
- Driving: charges from the alternator while the engine's running, through a DC-DC charger
- Solar: panels on the roof charge the battery during the day, through a charge controller (often called MPPT)
- Mains hook-up: plug into a campsite pitch and a battery charger tops up your leisure battery, while also powering your 230V sockets directly
Many vans use all three. Drive a lot and a DC-DC charger earns its keep. Camp off-grid and solar becomes valuable. Stick to campsites and mains hook-up may be all you need.
How do I know what size I need?
Start with your appliances, not the battery. Ask yourself what you want to power and for how long, whether you'll mostly use campsites or go off-grid, whether you'll travel year-round, and whether you need 230V or can run mostly on 12V.
A weekend camper with lights, phone charging and a small water pump needs a very different system to a full-time van running a fridge, laptop and induction hob. List your appliances, work out roughly how much you'll use each day, and the right battery size, charging setup and solar follow from that.
What a basic system includes
A typical beginner setup covers:
- a leisure battery
- a battery monitor
- a 12V fuse box
- lights, USB sockets, a water pump
- a fridge connection
- a way to charge
- the correct cables, fuses and isolators to tie it together safely.
An inverter gets added only if you actually need 230V power. The right system is the one that matches how you'll use the van, not the biggest one you can fit in.
Two ways to put it together
Once you know what you need, there are two ways to build the system. All-in-one power management units from brands like CBE and Sargent bring mains charging, 12v distribution, fusing, and monitoring into a single box, most often found in caravans and motorhomes but available for campervans too. The alternative is a modular approach, specifying individual components chosen for your specific build. We stock a range of components across various brands to suit both routes.
Safety isn't optional
Cable size and fusing matter more than anything else here. A fuse protects the cable and helps prevent overheating or fire if something goes wrong, and an undersized cable can get hot, especially on high-power items like inverters. If you're not confident wiring it yourself, get it checked by someone qualified.
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