Anyone else running a tiny house setup in a motorhome rather than a static build?

Been down the rabbit hole on this for a while now. My situation is a bit unusual — I'm trying to keep things genuinely tiny-house minimal but in a mobile format, so every kg and every cubic centimetre counts. Currently spec'ing out a 200Ah lithium bank using Fogstar Drift cells and a Victron SmartSolar 100/30 controller, with around 400W of panel on the roof.

The challenge I keep running into is balancing enough storage for genuine off-grid comfort (laptop, lighting, small induction hob occasionally) versus keeping the whole system light enough that it doesn't wreck payload. The Fogstar cells are great on weight vs capacity, but I'm still nervous about whether 200Ah is actually liveable for 3–4 days without sun in the UK. Anyone run similar capacity through a grey November week?

Also curious whether anyone's crossed over from static tiny house builds into motorhome living — feels like there's a gap in the conversation here. Most threads seem to either be full-on campervan weekend warriors or proper off-grid homesteaders, but the overlap is where I'm sitting. What does your setup look like?

Hey @Thommo, sounds like a brilliant approach honestly. The weight discipline you get from mobile living forces really honest decisions that static tiny housers often dodge.

One thing worth considering if you haven't already — your battery bank is usually where the weight creep sneaks up on you. I run lithium rather than AGM purely because the weight saving per usable kWh is significant, and in a motorhome that actually matters for payload and handling.

Also worth thinking about your solar placement early doors. Flush-mounted panels save faff with wind noise and clearance heights, but you lose some tilt efficiency. Tradeoffs everywhere!

What sort of mileage are you planning annually? That changes the whole equation around whether you can rely more on alternator charging versus needing a beefier roof setup. Happy to chat through specifics if useful.

Great thread @Thommo. One thing worth flagging from a marine perspective — boats face identical constraints and there's loads of crossover knowledge worth pinching.

The lithium vs AGM debate in the narrowboat community maps almost perfectly onto motorhome builds. Victron kit dominates both worlds for good reason, and their smaller MultiPlus units are genuinely space-efficient.

On the weight side, have you considered swapping any cabinetry for composite marine ply? It's pricier but significantly lighter than standard furniture board and handles moisture far better in a mobile environment.

Also worth looking at 12v compressor fridges designed for marine use — brands like Isotherm or Indel B are built around tight spatial packaging that transfers brilliantly to your situation.

What's your current power setup looking like? That usually dictates everything else downstream in a build this constrained.

Really relate to this @Thommo — I've been running essentially a tiny house philosophy in my Transit conversion for two years now and the mobile constraint genuinely improves your decision-making. You stop entertaining any "yeah but maybe I'll need it" purchases pretty sharpily.

One thing I'd add that hasn't been mentioned — think carefully about your energy architecture before anything else goes in. Once cabinetry and fixtures are fixed, retrofitting a bigger battery bank or repositioning solar becomes a nightmare. I planned mine around a 200Ah lithium setup from the start and left deliberate routing space for cabling. Saved me a complete rip-out later.

Also interested what @QG_Marine has to say — the crossover between narrowboat/yacht builds and van conversions is massively underappreciated on here. Some clever marine solutions translate directly.

What's your current thinking on power @Thommo?

Great thread @Thommo. Something I'd add that nobody's touched on yet — thermal mass is the one tiny house principle that simply doesn't translate to mobile living, and it took me a while to make peace with that. Static builds lean heavily on rammed earth, concrete floors, stone walls etc. to regulate temperature passively. In a motorhome you've got none of that, so your insulation strategy has to work much harder and your heating system needs to respond quickly rather than slowly. I switched my thinking from "store heat" to "generate heat efficiently on demand" and everything clicked after that. A decent diesel heater with a proper thermostat does the job nicely. @QG_Marine is right that the marine world has solved a lot of this already — worth raiding narrowboat forums too, they've been living this problem for decades.

My static caravan was the gateway drug, but the van conversion is where the real space Tetris begins — swapped a Fogstar 200Ah for a slimline 100Ah just to reclaim a shelf, and honestly don't regret it one bit.