Anyone else finding 12V vs 24V decisions genuinely confusing when starting out?

I've been planning my first proper off-grid van build for about three months now and I keep going round in circles on this one. Started with a 12V design, got to around 300Ah of lithium and a 2000W inverter on the wishlist, then someone on a Facebook group told me I should just go 24V from the off. Now I'm not sure which way to turn.

The way I understand it, 24V means thinner cable runs, less voltage drop over long distances, and the inverter tends to run more efficiently at higher loads — which matters because I want to run a small induction hob occasionally. My van is a long-wheelbase Transit, so the cable runs from the battery box under the bed to the consumer unit aren't exactly short. We're talking maybe 2.5–3 metres.

What I can't work out is whether the cost and faff of 24V kit (chargers, DC-DC, solar charge controllers that handle it properly) actually pencils out for a single-van leisure build rather than, say, a full-time liveaboard setup. Has anyone here made the switch mid-plan, or started 24V from scratch on a similar size build? Would love to hear what swung it for you and whether you'd do it the same way again.

Foggy91 | 847 posts

@MarineTerry the bit that finally made it click for me was thinking about wire runs rather than the batteries themselves. Once you're pulling serious amps through 12V, your cable costs and losses become a proper headache. I ran the numbers on my setup and the saving on decent 70mm² cable alone basically offset the cost of a 24V inverter.

That said, if most of your loads are small 12V things - lighting, a fridge, USB charging - you can comfortably stay at 12V and just step down from 24V if needed with a DC-DC converter.

What's your biggest planned load? That's honestly the deciding factor more than the battery capacity figure. A 2000W inverter on 12V is absolutely doable but you'll want to check your BMS can handle those peaks comfortably.

DorsetExplorer | 312 posts

@MarineTerry three months of planning sounds about right honestly — I went round the same loop before my motorhome build! 😄

One thing that helped me: at 300Ah+ with a 2000W inverter, 24V starts making real sense purely on fuse/cable sizing. Halving the current means you can run much more manageable cable gauges throughout.

I went 24V with Fogstar Drift cells and a Victron MultiPlus — genuinely the best decision I made. Victron's kit is pricey but the ecosystem just works together.

Don't stress too much though — loads of brilliant 12V builds out there too. Whatever you choose, commit and crack on! The planning paralysis is the real enemy. 🔧