Borrowed a neighbour's petrol genny last winter — worth getting my own small one as backup?

Having run a motorhome setup for a few years now, I'd say a small petrol genny is genuinely worth having as a backup, but with some caveats worth thinking through first.

The main issue with petrol units is fuel shelf life — petrol degrades surprisingly quickly, especially with ethanol blends. If it's sitting there "just in case," you'll want to either use a fuel stabiliser like Briggs & Stratton's treatment or run it through every couple of months. Learned that the hard way with a carb that needed cleaning out.

For occasional backup use, something like a Honda EU22i or the slightly cheaper Hyundai HY3000SEi hits a decent balance between portability, noise levels, and clean enough sine wave output for sensitive electronics. The inverter-type gennies are worth the premium if you're running anything with a battery charger — a Victron IP22 or similar will thank you for it.

Capacity question: what are you actually trying to power? If it's just keeping a Fogstar or similar LiFePO4 bank topped up during a prolonged gloomy spell, a 1–2kW unit is probably sufficient. If you're wanting to run heating, a kettle, and charge simultaneously, you'll want to size up accordingly.

Also worth considering: CO risk if you're tempted to run it in a garage or outbuilding with poor ventilation. Sounds obvious but it catches people out.

My honest take — borrow someone's for a weekend first and log what you actually need it to do before committing. The market is full of cheap units that sound tempting but won't last.

What's your current battery setup and typical winter load looking like? That'd help narrow down the right size.

@Curly — really interested in this thread as I'm weighing up the same question for my narrowboat. The petrol vs propane/LPG generator angle is something I keep coming back to — on the cut, storing large quantities of petrol is a genuine headache from a safety and insurance standpoint.

Has anyone here run a small dual-fuel unit as backup? I've seen a few Honda EU22i alternatives that apparently handle LPG reasonably well. The appeal for me is that I've already got a 13kg propane setup aboard, so piggybacking off that for emergency top-ups to the Victron system feels more practical than keeping jerry cans around.

What kind of runtime are people actually getting on LPG at low load compared to petrol? The figures I've seen look promising but real-world narrowboat or confined-space experience would be really useful here.

@Curly good timing on this thread — just went through exactly this decision for my garden office setup last autumn.

One thing nobody's mentioned yet: fuel stabiliser is non-negotiable if you're buying a petrol genny for occasional backup use. Ran a Honda EU22i for 18 months as emergency backup and the carburettor gummed up completely from sitting with old fuel. Costly lesson.

Also worth considering — if your primary system is Victron-based, a small inverter genny with clean sine wave output plays much nicer with the MultiPlus charger than a cheap Chinese unit. The Honda and Yamaha EF2200i are the go-to recommendations for good reason, even if the price stings.

@MasterProject narrowboat is interesting — LPG might actually make more sense for you given you're likely already running gas onboard anyway. Dual-fuel units are worth a look.

Petrol goes stale faster than my enthusiasm for rewiring the shepherd's hut in January — kept a small Honda EU22i for the cabin and the carb gummed up after one lazy summer of neglect.

Sta-Bil in every fill, no exceptions.

For genuine backup duty rather than daily use, honestly consider whether a propane unit makes more sense — fuel stores indefinitely and the Victron Multiplus doesn't care what charges it, as long as something does during a February solar drought.

Spent 40 years as a spark, so backup power isn't optional for me — it's a personality trait.

Got a Honda EU22i in the shed alongside my static caravan setup. Petrol storage is the real faff though. I rotate mine every 8 weeks and treat it with Aspen or a fuel stabiliser, otherwise you're just filling a