Anyone else running 12V vs 24V in a tiny build — worth the hassle of upgrading?

Started out with a 12V system in my shepherds hut — 200Ah Fogstar Drift LiFePO4, couple of 175W panels, Victron SmartSolar 100/30. Works fine for lighting and phone charging but struggling a bit when I run the diesel heater fan and a small 12V compressor fridge simultaneously. Seeing some voltage sag and the cables are starting to feel like a compromise.

Been reading that 24V halves your current for the same wattage, so thinner cables, less loss, all that. Tempted to swap the battery bank and get a Victron Multiplus 24/800 in there, but it feels like a lot of faff to redo everything — fusing, inverter, existing 12V loads.

Has anyone actually made the jump mid-build rather than starting fresh at 24V? Wondering if it's genuinely worth it or if I should just beef up the cable runs and stick with 12V. The hut's only about 14 square metres so I'm not pulling massive loads — probably 400-500Wh a day average.

@FX_Power that's almost exactly my setup from 18 months ago — same hut context too. The tipping point for me was when I added a decent inverter and the cable runs started getting silly thick to keep voltage drop manageable. Went to 24V last spring and honestly the difference in efficiency was noticeable straight away, especially on cloudy days when every watt counts.

Worth flagging: if you're running 12V appliances throughout (USB hubs, 12V lighting strips etc.) you'll need a DC-DC converter after upgrading, which adds a small complication. But the Victron Orion-Tr handles that cleanly.

Main question is — what are you actually trying to add? If it's just a small inverter for a laptop, you might squeeze more from 12V first before committing to a full rewire.

WonkyRanger | 847 posts

@FX_Power the wire gauge issue is what catches most people out at 12V — you're essentially doubling your current compared to 24V for the same wattage, so cable runs become expensive and lossy pretty quickly in a small build. That said, your Victron MPPT will need replacing if you go 24V since the 100/30 is 12V nominal output only.

Genuinely though, if your panels are already wired series-parallel and you've got headroom on the Fogstar BMS, sometimes just adding a 12V inverter-charger and managing loads more carefully buys you another year before committing to a full rewire. What loads are actually causing the struggle — is it an inverter you're running, or just voltage sag under sustained draw?

CoastalCruiser | 312 posts

@FX_Power the voltage drop over longer cable runs is genuinely painful at 12V — even a few metres can cost you meaningful efficiency. That said, for a shepherd's hut specifically, I'd actually question whether upgrading is worth the faff before you've maxed out what 12V can do. Have you looked at your actual load profile? If your peak draw is sitting under 1,500W, a well-wired 12V system with decent cable sizing will serve you perfectly well. The 24V jump makes more sense when you're running larger inverters or the hut is particularly spread out. Swapping your MPPT and potentially rewiring everything is a significant cost — that money might be better spent on an extra battery first.