Anyone else running a small inverter generator alongside solar for winter backup — what's your setup?

So I've finally caved and picked up a Honda EU22i after two winters of being caught short when we had a run of grey weeks and the 400Ah LiFePO4 bank just couldn't keep up. The solar (2x 200W panels, Victron MPPT) is brilliant from March through to October but December and January are a proper struggle up here in the Peak District — we're talking 0.5 to 1kWh on a bad day when I need 2.5kWh minimum to run the fridge, a bit of lighting, and keep the woodburner fan ticking over.

The EU22i is dead quiet compared to what I expected and sips fuel — I'm getting about 3–4 hours of charging out of a litre of petrol when I'm pushing roughly 1,400W into a Victron Multiplus 24/1200. That feels reasonable but I'm not sure I've dialled in the settings properly yet. I've got the absorption voltage set to 28.8V and float at 27.6V but I wonder if I'm cutting the generator off too early or late.

Has anyone got a similar hybrid setup working smoothly through winter? Particularly interested in whether you automate the generator start in any way — I've seen the Victron "generator auto-start" feature mentioned but not sure how well it works in practice with a non-smart generator like the Honda.

@RussWilson solid move on the EU22i — Honda's inverter output plays nicely with most chargers.

Running a similar setup on my shepherd's hut — 2x 175W panels into a Victron SmartSolar, 200Ah Fogstar Drift LiFePO4. Added a Firman inverter genny last autumn and it's been a game changer for the grey spells.

One thing worth checking — what charger are you using to bring the bank back up from the genny? I'm curious whether you're running it through a dedicated AC charger or just relying on the solar controller somehow?

I found connecting via a Victron IP22 Blue Smart charger meant the MPPT and AC charger could both talk to the battery properly without fighting each other. Made a noticeable difference to charge times on overcast days.

What battery management setup are you running alongside the bank?

Good shout @RussWilson — I made the same call last autumn and haven't looked back. One thing worth considering is running the EU22i in eco mode while charging; it throttles down nicely once the charger backs off demand and the fuel savings are genuinely noticeable over a long session.

I've got mine wired through a proper transfer switch rather than just plugging in ad hoc — makes the whole process much cleaner and means the other half can run it without any faff if I'm not around.

What charger are you pairing it with? I found a decent DC-DC unit made a bigger difference than I expected compared to just using a standard mains charger. Worth thinking about if you haven't already sorted that side of things.

Great thread @RussWilson — the EU22i is a cracking bit of kit for exactly this situation.

One thing I'd add that nobody's mentioned yet: keep an eye on your battery SoC and set a threshold to kick the generator in before you're scraping the bottom of the bank. I run mine set to trigger at 30% rather than waiting until I'm desperate — means the Honda's only running an hour or two to top things back up rather than grinding away for half a day.

Also worth investing in a decent smart charger rather than relying on whatever's built into your inverter. Mine's a Victron IP22 and it talks properly to the LiFePO4 chemistry. Made a noticeable difference to charge times.

What are you using to charge from the generator output — going straight into the inverter/charger?

Great choice @RussWilson — the EU22i is a cracking bit of kit. One thing I'd add that nobody's mentioned yet: keep an eye on your charger's input power factor when running it off the Honda. Some cheaper MPPT/chargers with poor PFC can cause the generator to hunt or run roughly even though it's well within the rated wattage.

Also worth setting a minimum state of charge trigger on your BMS or battery monitor so you're not running the genny unnecessarily — I've got mine set to kick off a manual charge cycle when the bank drops below 20%, which on a 400Ah LiFePO4 gives you plenty of headroom before anything critical.

Winter top-ups tend to be short runs too, so make sure the EU22i gets a decent load on it rather than light-loading for hours — better for the engine long term.

Running a similar setup in my van — 200W panel and a 100Ah Fogstar Drift LiFePO4. Winter is brutal when you're parked up in a shaded spot for days.

Quick question for anyone who's done this: when you're charging via the generator, are you going straight into a mains charger (like a Victron Blue Smart IP22) or running it through an inverter-charger?

I've been eyeing up the Victron MultiPlus route so everything's integrated, but wondering if that's overkill for occasional top-up use and whether a standalone charger would do the job just as well for less money.

Also @RussWilson — how long does a tank in the EU22i typically last you at partial load? Trying to work out whether the running costs are realistic for a week-long stint parked somewhere remote.

Great thread! I run a similar hybrid approach — EU22i paired with 600W of solar and a 200Ah LiFePO4 bank in my garden office setup.

One thing I've found really useful that hasn't been mentioned: I run mine through a smart plug with a CT clamp monitoring the battery, so it only fires up automatically when SOC drops below 20%. Saves fuel massively compared to running it on a schedule, and means I'm not constantly babying it.

@VanLee — parking orientation makes a surprising difference in winter doesn't it? Even a 15° angle improvement towards south can squeeze meaningful extra charge out of those short days.

Worth investing in a decent battery-to-generator interlock if you haven't already @RussWilson — stops the inverter and generator fighting each other. Victron's stuff handles this elegantly if you're ever looking to expand the system.

Something nobody's flagged yet — worth setting a low-voltage cutoff on your Victron (if that's what you're running) so the generator kicks in automatically rather than waiting until you notice the bank's tanked. Saves a lot of faff in the dark.

Also on the EU22i, run it at least once a month even if you don't need it. Let it warm up properly and put a decent load on it. Sitting unused with old fuel in the carb is what kills these things over winter.

Good shout from @CurrentAffairs96 on the low-voltage cutoff — that's saved my bacon more than once. One thing I'd add for @RussWilson specifically: with the EU22i, it's worth running it at a decent load rather than just ticking over. These little Hondas don't love being lightly loaded for extended periods — can cause wet stacking over time. I usually wait until my bank's down to around 30-40% then give it a proper charge cycle rather than topping up in short bursts. Much better for the generator and gets your battery charged more efficiently too.

Good timing on the EU22i — solid choice. One thing worth mentioning that hasn't come up yet: if you're using the generator to charge via a proper charger rather than just running loads directly, it's worth matching your charge current to what the generator can comfortably sustain. The EU22i is rated 1.8kW continuous, so don't push a charger set to pull its full rated output or you'll hear the engine labour and potentially trip. I keep mine set to about 70% of generator capacity — runs quieter, uses less fuel, and the eco-throttle works a treat at that level too. @RussWilson what charger are you running with it?

Dead right on all the above. Something I'd add from running my shepherd's hut through two grim Novembers — don't underestimate the value of a smart schedule. I set my Victron MPPT to flag when state of charge drops below 40% by early afternoon, which gives me enough daylight left to run the EU22i before it gets dark and cold rather than scrambling at 10pm. Makes a huge difference to how efficiently the generator charges too — warmer batteries accept current far better. The Honda paired with a Victron MultiPlus is a genuinely tidy combination once you've dialled in the settings.

Great setup @RussWilson, the EU22i is a cracking little unit. One thing worth adding to what's been said — keep an eye on your charge current relative to that 400Ah bank. The EU22i puts out around 1800W continuous, so if you're pushing the full lot through a charger, you want to make sure you're not exceeding your battery's recommended charge rate (typically 0.5C for LiFePO4, so around 200A max on your bank). Easy to overdo it when you're keen to top up quickly after a grey spell. A decent quality B2B charger with adjustable output gives you proper control over that.