Generator für Inselanlage

Been thinking about this a lot lately for my motorhome build but it applies to my tiny house setup too — what generator do you actually pair with a LiFePO4 system as a proper backup?

My current setup is roughly 3kWh of Fogstar Drift cells with a Victron MultiPlus handling the inverter/charger side. Solar does the heavy lifting most of the year but November through February in the UK is just... grim. Panels barely producing anything useful.

Few things I'm confused about:

• Does the generator output need to be "clean" enough for the Victron to accept it, or will it just handle whatever you throw at it?
• Is there a minimum wattage worth bothering with? I've seen cheap 2kW units on Amazon but they look sketchy
• Honda EU series seem to be the gold standard but the price is mental — anyone running a Hyundai or similar budget inverter genny with good results?

Also wondering whether a generator even makes sense vs just throwing more panels at the problem and accepting winter is rubbish. My roof space is limited though so I can't just keep stacking.

The German thread that inspired this was talking about a 4500Wp system with 7kWh storage which is considerably bigger than mine — presumably at that scale a genny becomes more sensible because you've got more to charge and higher loads to cover?

Anyone running a similar-sized UK system with a generator actually integrated properly rather than just as an emergency "plug something in" situation?

@EcoFlowMaster for a shepherd's hut setup I've been running a Honda EU22i paired with a Victron MultiPlus-II, and the combination is genuinely excellent. The inverter-generator's clean sine wave plays nicely with the Victron's charge algorithm, and you're not hammering the generator at low load.

Key thing most people miss: size your generator to the MultiPlus input current limit, not the battery bank. My 200Ah Fogstar Drift LiFePO4 cells can theoretically accept charge far faster than a modest genny can deliver — so let the MultiPlus throttle the AC input accordingly via PowerAssist.

For UK buyers, the Hyundai HY3000SEi is worth considering at roughly half Honda's price. Noisier, but the fuel consumption under partial load is competitive.

Avoid fixed-speed generators with LiFePO4 — the voltage wobble causes grief with more sensitive BMS configurations.

Interesting question — on my boat I've been wrestling with exactly this. The Honda EU22i @LiamFrost70 mentions is solid but I've been looking at the Yamaha EF2200iS as an alternative — anyone had direct experience comparing the two with a Victron charger?

My main concern is whether the inverter generator's output is "clean" enough not to cause issues with the MultiPlus AC input sensing. Had some weird behaviour last season that I couldn't pin down — might have been the cheap generator I borrowed.

Also worth asking — what's the minimum kW rating people recommend for sensibly charging a 200Ah LiFePO4 bank without the generator hunting under load?

Been running a Fogstar Drift 200Ah bank in my shed setup for about 18 months now. For backup charging I went with a Yamaha EF2200iS — bit cheaper than the Honda but still inverter-type so the Victron MultiPlus handles it no bother.

Key thing people miss with LiFePO4 backup charging is matching your generator output to what your charger can actually accept. No point running a 2.2kW genny at 10% load — kills it long-term.

I'd also look at whether you actually need a separate genny. Depending on your solar array size and battery capacity, a decent Victron MPPT setup might mean the generator only fires up 3-4 times a year anyway. Mine barely gets used now tbh.

@Wayne1980 what inverter are you using between that genny and the Fogstar bank though? That's the bit people always gloss over.

A generator into a LiFePO4 system without a proper inverter-charger in the middle is asking for trouble — voltage spikes, poor charge acceptance, the lot. Victron MultiPlus-II is the obvious answer but even a cheaper Victron Phoenix Inverter paired with a decent MPPT will sort you.

Also worth noting — generator output quality matters. Cheap non-inverter generators produce dirty AC. Fine for power tools, not ideal when your charger is trying to do proper CC/CV charging into lithium cells.

Honda EU22i is the gold standard but pricey. Yamaha EF2000iS is worth a look if budget's tighter.

@BatteryTim raises the real question — on my narrowboat I made the schoolboy error of pairing a cheap generator directly with a Victron MultiPlus and nearly had a very expensive bonfire.

For LiFePO4 specifically, inverter generators only — the clean sine wave matters more than people realise when the Victron's doing the clever stuff.