What's your actual emergency power setup in the motorhome — not the fantasy version?

Been thinking about this after a recent trip where my 240Ah Fogstar Drift LiFePO4 bank got properly tested during three days of solid overcast. Shore power wasn't an option, the 200W of Renogy panels on the roof were doing virtually nothing, and I genuinely had to think hard about what was critical versus what was nice-to-have.

My "emergency" layer ended up being a 1000W Ecoflow River 2 Pro I'd shoved in the garage locker almost as an afterthought, plus a 12V Victron IP65 charger wired to the leisure bank via a small Honda EU22i generator. Together they bridged the gap fine, but it felt more like luck than planning. The Victron MPPT 100/30 and the BMV-712 at least gave me solid data throughout, so I could see exactly how bad the situation was in real time — that bit worked as intended.

What I'm wondering is whether anyone here has actually sat down and designed their emergency fallback properly — defined minimum loads in watts, calculated how many hours the backup source covers them, and chosen their generator or secondary battery with that maths in mind rather than just buying what seemed reasonable at the time? Curious whether people are treating it as a genuine engineered layer or just hoping for the best.

SilverTrekker | 847 posts

Ah, the classic "three days of grey Welsh sky stress test" — we've all been there @DefenderDream!

My actual setup rather than the dream: 300Ah of Fogstar Drift cells, 300W of panels (which in reality means about 180W on a good day), and a Victron SmartSolar MPPT. The thing that genuinely saved us last autumn in the Highlands was adding a Sterling B2B charger pulling from the alternator during driving days. Even a 90-minute drive topped things up meaningfully.

Honestly the B2B was the single most practical addition I've made. Solar gets the glory but driving between spots is what actually keeps our fridge running through grim weather.

Also keep a small Jackery as a genuine emergency backstop for phone charging and medical kit. Dead cheap insurance.

What's your split between driving days and static days when this happened?

KevScott | posts

Not a motorhome but the principle's identical on the boat — three days of solid grey and you find out fast what your "emergency" setup actually is versus what you thought it was.

My actual fallback when solar's doing nothing: a Victron Orion TR Smart running off the engine alternator. 30 minutes of motoring buys me enough to run the essentials through the night. Not glamorous, not free, but it works.

Secondary to that I've got a small Honda EU22i generator that lives in a deck locker — dead reliable, whisper quiet, and it'll happily top up via the Victron MultiPlus without drama.

The honest truth nobody wants to admit: lithium gives you more usable capacity but it doesn't magic away the recharging problem. You still need a reliable input source when weather turns.

Stacey72 | 312 posts

Ours is nothing glamorous but it works — 180Ah Fogstar Drift bank (noticing a theme on this forum!) with 160W of panels on the roof, which frankly isn't enough. The honest answer to the thread title is: a Jackery 1000 Plus sitting in the wardrobe as the actual emergency backup when the main system disappoints.

The thing nobody mentions is how much you're quietly rationing before you consciously realise you're doing it. Three overcast days and I'm suddenly very interested in whether the kettle really needs boiling twice at breakfast.

We've also got a Victron SmartShunt now which at least means I'm watching the battery die with precision. @KevScott boat life must make this even more stressful — no popping to a campsite with hookup as a fallback!

XJ_Solar | 203 posts

Static caravan rather than motorhome but same problem hits us — extended grey periods in autumn are brutal.

Backup layer that actually saved us last October: a cheap 1000W petrol genny tucked in the shed. Not glamorous, not quiet, but two hours running topped the Victron MPPT back up enough to cover essentials for another day. Paired with a Victron SmartShunt so I can actually see the state of play before it gets critical rather than after.

@DefenderDream the mistake I made early on was treating solar as primary and having nothing behind it. Now solar is primary, battery is buffer, genny is emergency — that hierarchy mindset changed how I managed consumption completely.

Biggest lesson: know your actual daily Wh draw before you need to stretch it across three dark days.

RobButler | 847 posts

Similar story here — 200Ah Victron LiFePO4 paired with a Victron Multiplus 12/1200. The real emergency backup that's saved us twice now is a Honda EU22i genny tucked in the external locker. Yes it's not very off-grid purist but three hours running charges the bank to 90% and you're sorted. The Victron comms between the MPPT, BMV-712 and Multiplus means I can see exactly where I stand before things get critical rather than after.

@DefenderDream honestly 200W of panels is where I'd be looking first — that's quite modest for a 240Ah bank when you're in the UK shoulder seasons. Even adding another 100W panel made a noticeable difference for us before I eventually caved and got the Honda. Belt and braces wins over principles when you're parked somewhere properly remote.

Cleggy83 | 156 posts

Honest answer — 100Ah Fogstar Drift (yes, another one 😄), 175W panel on the roof, and a little Honda EU22i petrol genny as my actual get-out-of-jail card. The genny's the bit I never mention first because it feels like admitting defeat, but three days of November grey near Appleby last year and it was absolutely the right call. Topped the bank up properly in under two hours.

One thing I'd add that nobody's mentioned — I keep a separate small 20Ah battery isolated from the main bank purely for the alarm and a basic light circuit. Proper belt-and-braces stuff but it's saved me once already when I managed to drain the main bank further than I'd like to admit. @RobButler the Multiplus setup sounds very tidy, mind.