12V vs 24V vs 48V

Nominal system voltage is one of the first decisions you make, and it shapes everything downstream: cable sizes, fuse ratings, which inverters and chargers you can buy, and how forgiving the whole system is. The key physics is simple — for the same power, doubling the voltage halves the current.

12 V — the campervan default

12 V matches vehicle electrics, has the widest range of cheap accessories (fridges, sockets, pumps, lights) and is simple to wire for a small system. The catch is current: anything power-hungry, like a 2,000 W+ inverter, pulls huge amps and demands very thick, expensive cable. For modest builds under roughly 1,500–2,000 W of inverter load, 12 V is usually the pragmatic choice.

24 V — the comfortable middle

24 V halves the current of an equivalent 12 V system, so cables get thinner and cheaper and runs are more efficient. It suits larger vans and boats with bigger inverters and air-conditioning. The trade-off is fewer plug-and-play 24 V accessories, so you often add a DC-DC converter to feed a 12 V accessory rail.

48 V — for big, demanding systems

48 V is the choice for cabins and high-power builds with several kilowatts of inverter and a large battery bank. Current drops further still, wiring becomes genuinely manageable, and high-power inverters are designed around it. It is overkill for a simple weekend van, and almost everything 48 V is a dedicated component rather than a vehicle accessory.

How to decide

Let your largest continuous load decide. If your peak inverter draw keeps the main cable current reasonable (broadly under ~150 A), 12 V is fine. As inverter size climbs, step up to 24 V and then 48 V to keep currents — and cable costs — under control. When in doubt, size your loads first, then pick the lowest voltage that keeps your main cables sane.