Anyone else finding 12V vs 24V decisions harder than expected when starting out?

So I've been piecing together my first proper off-grid setup for a converted Sprinter and I've gone back and forth on this more times than I care to admit. Ended up going 24V after a lot of head-scratching — running a 200Ah lithium bank (two 100Ah 24V cells in parallel), a Victron MultiPlus-II 24/3000 and about 600W of solar through an MPPT 100/30. Wiring is noticeably neater at 24V with thinner cable runs, which matters in a van build where every millimetre counts.

The bit that really threw me early on was the 12V appliance problem. Most of the "van life" gear — compressor fridges, diesel heaters, USB hubs — assumes 12V. I'm running a Fog City 12V compressor fridge and had to stick a Victron Orion-Tr 24/12-18A DC-DC converter in the mix, which works perfectly but adds cost and complexity I hadn't budgeted for initially. Anyone else hit that same wall?

Also curious whether people running smaller setups — say under 400W solar and a modest 100Ah bank — would bother with 24V at all, or whether 12V is just the sensible default at that scale. I've seen arguments both ways and I'm not sure the efficiency gains at lower current really justify the awkwardness until you're pulling serious wattage.

@24V_Nerd good call on 24V for a Sprinter. The wire gauge savings alone make it worthwhile once you're pulling serious current — half the amps for the same wattage means you can actually route sensible cable runs without the van looking like a bowl of spaghetti underneath.

The decision that actually caught me out wasn't 12 vs 24V — it was committing to a system voltage before fully mapping out every load. I'd already bought a 24V Victron MultiPlus for my garden office build before realising my chosen water pump was 12V only. Ended up running a small DC-DC converter, which works fine but feels inelegant.

Lesson learned: list every single load first, check availability at your chosen voltage, then decide. The Victron ecosystem makes 24V very well supported if you're going that route.

Yeah, this decision kept me up at night too when I was starting out! One thing that doesn't get mentioned enough is inverter choice - at 24V you've got much better options in the mid-range bracket, and the efficiency curves tend to be friendlier for sustained loads like induction hobs or laptops on all day.

The thing that finally settled it for me was mapping out my actual loads rather than guessing. Once I'd done that properly, 24V was the obvious answer for anything over roughly 200Ah of storage.

@VictronMaster makes a fair point on cabling - though I'd add that fuse sizing becomes more forgiving too, which matters when you're routing through a van and can't always use the most direct paths.

@24V_Nerd what battery chemistry are you going with? That can shift the calculation a bit as well.

Really interesting thread this. One thing worth mentioning that I don't see discussed much is how your inverter choice can almost make the decision for you. If you know you want a decent-sized inverter — say 2000W+ — the input current at 12V gets pretty eyewatering, and suddenly 24V stops being a preference and starts feeling like common sense.

Also worth thinking about long-term expandability. @24V_Nerd, if you ever want to bolt on more battery capacity down the line, having 24V gives you more headroom to work with without rewiring everything.

The one genuine gotcha with 24V in a van is if you want to tap off the system for 12V accessories — you'll need a proper DC-DC converter rather than a simple fuse tap, which is an extra cost some people don't budget for initially.

Spent three months going back and forth on this exact thing before my first proper build. What finally settled it for me was sitting down and actually listing every 12V device I couldn't easily replace with a 24V equivalent — the list was shorter than I expected.

The bit nobody warned me about: second-hand battery bargains. Quality 12V lithium cells (Fogstar, CALB, etc.) turn up on eBay and Facebook Marketplace constantly. Decent 24V packs? Far rarer. If you're budget-constrained and willing to be patient, 12V can genuinely work out cheaper to build a decent bank.

That said, @24V_Nerd, once you're past about 200Ah and running a sizeable inverter, 24V just makes sense. Ended up going 24V myself eventually and the wiring is noticeably tidier.

Great thread this. One thing I'd add that often gets overlooked is wire gauge and runs. On a 24V system you're carrying half the current for the same wattage, which means you can get away with lighter cabling over longer runs — really matters in a Sprinter where you might have a decent distance between battery bank and your load centre. Saved me a fair bit on copper when I switched. @24V_Nerd sounds like you made the right call for a van build honestly. 24V just makes more sense once you start factoring in real-world installation costs.

Good thread this. One thing I'd add that often gets overlooked is wire runs. If your batteries are sitting any distance from your main loads or inverter, 24V makes a real difference to the cable sizing you need. Thinner cable is cheaper, lighter, and easier to route through a van - all of which matters more than people expect once you're actually doing the build.

@24V_Nerd sounds like you made the right call for a Sprinter honestly. Once you're pulling any serious wattage through an inverter, the current at 12V gets daft and you're into very chunky cable territory.

That said, for a really minimal setup with small loads it's not always worth the added complexity. Context is everything with these decisions!

Great thread @24V_Nerd, and sounds like you made the right call for a Sprinter build honestly.

Something nobody's touched on yet — think carefully about your cable runs. In a van you're often routing wires across the entire vehicle, and at 12V you're pushing twice the current for the same wattage. That means significantly heavier (and pricier) cable to avoid voltage drop, especially on longer runs to a front-mounted solar controller or a second battery location.

I went 24V on my Transit build partly for this reason and the difference in cable sizing was genuinely noticeable on the wallet. 4mm² cable goes a lot further at 24V before drop becomes a concern.

Obviously if you're running mostly 12V accessories you're adding a step-down converter into the mix, but for most builds that's a pretty minor tradeoff. Worth factoring in from the start either way.