Has anyone run a wood gasifier alongside solar for winter cabin power?

I've been mulling over a hybrid setup for my wee cabin up in Perthshire and keep coming back to the idea of pairing a small wood gasifier with the existing 400W solar array and 200Ah lithium bank. The solar does fine from April through September but the winters here are brutal — we're talking weeks of low cloud and barely 2–3 hours of usable sun a day. The batteries are half-dead by November without some other input.

A gasifier running on dry hardwood or wood pellets could theoretically feed a small genset head and top up the bank on gloomy days, and I'd have no shortage of timber on the plot. I've been looking at the Imbert-style downdraft designs — some folk on the continent seem to be running 5–10kW units for exactly this kind of thing. Tar contamination in the engine seems to be the big killer if you get the moisture content wrong, though.

Has anyone actually done this in a UK setting, particularly somewhere with damp wood and unpredictable weather? I'm curious whether the faff of drying, filtering, and maintaining the gasifier outweighs just buying a decent propane genset as backup. Would love to hear from anyone who's gone down this road — even if it ended in disaster.

HamishLee | 47 posts

@HighlandOffGrid cracking idea for Perthshire winters - those short December days will have your 400W array barely ticking over. I ran a small Imbert-style gasifier alongside solar at my place in Argyll for two winters and the complementary nature of the two sources is genuinely brilliant. When it's grey and gloomy, you're often burning wood anyway for heat, so you might as well be generating simultaneously.

One practical tip - gasifier output is quite variable until the system reaches operating temperature, so I'd strongly recommend running it through a decent charge controller rather than direct to your lithium bank. Cold starts can produce some nasty voltage spikes.

Also budget serious time for tar management - it's the unglamorous reality nobody mentions upfront. What generator head were you considering pairing with it?

Robbo51 | 213 posts

@HighlandOffGrid I ran something similar for two winters at my place in Dumfriesshire - small Imbert-style gasifier feeding a converted Honda generator. The key thing nobody mentions is the syngas quality in damp conditions. Scottish winters mean wet wood unless you're storing it properly for 12+ months, and poor gasification absolutely hammers your engine over time.

What I'd suggest is treating the gasifier as your baseload overnight charger rather than trying to run it continuously. Let the solar handle daytime when you get those occasional bright spells, then fire the gasifier up for a few hours each evening to top the lithium bank back up. Worked a treat for me.

Also worth looking at what @HamishLee touched on - the December day length issue is brutal up your way. Your 400W array will feel like 150W in real terms come November.

ValleyOffGrid | 89 posts

Done exactly this with my van build — not a cabin, but the principles translate. The gasifier's biggest headache isn't the electrical integration, it's feedstock moisture. Scottish winters mean damp wood unless you're seriously disciplined about storage. Anything above 20% moisture content and your syngas quality tanks, which hammers your generator efficiency right when you need it most.

I've got a Victron MultiPlus handling the blending between sources and it manages priority charging beautifully — your 200Ah bank stays topped without the gasifier running unnecessarily.

Worth looking at whether your existing MPPT charge controller has a shared DC bus setup. The transitions between solar and gasifier-fed generation can cause voltage spikes that are unkind to lithium cells if your BMS isn't up to scratch. What BMS are you running in that battery bank?

SussexWanderer | 134 posts

@HighlandOffGrid Great thread. One thing nobody's mentioned yet — moisture content of your wood is absolutely critical with gasifiers, far more so than with a regular stove. I'd strongly suggest investing in a decent moisture meter and aiming for sub-20% before you even think about running it. Freshly cut or poorly stored wood produces tar that'll gum up your system something awful.

Also worth considering: the gasifier's output isn't always consistent during warmup, so I'd wire it through a decent charge controller rather than direct to the bank. Gives you cleaner power going in and protects those lithium cells.

@Robbo51 curious what generator head you paired with your Imbert — did you go permanent magnet or something off a retired Honda?

PanelPaula | 47 posts

Not running a gasifier myself but following this closely — my static caravan setup has the same winter solar problem (south-facing array but terrible December output up here). A couple of questions for those who've actually done this:

• How are you integrating the gasifier output into the battery bank? Going through a Victron MPPT or straight AC via an inverter-charger?
• What's the startup time realistically before you're getting usable power from the gasifier?

@SussexWanderer makes a good point on moisture — I imagine wet Scottish winters make that even more of a headache in Perthshire than down south. @HighlandOffGrid are you planning to store wood under cover well in advance?

Genuinely considering whether something like this could solve my own winter charging gap rather than just throwing more panels at the problem.

SomersetNomad | 312 posts

@HighlandOffGrid The elephant in the room with gasifiers is tar management — everybody talks about the kW output, nobody talks about cleaning the bloody thing every 40-50 hours. I run a small Imbert-type unit alongside 600W of Renogy panels on the boat, and the maintenance overhead is real. Factor that into your winter workflow before you get excited about "free" wood gas.

Also worth noting: your Victron MPPT (assuming you've got one) will need careful priority configuration so the gasifier-fed generator charges batteries without fighting the solar input. Victron's ESS assistant handles this reasonably well but it took me three firmware iterations to stop it behaving like a confused labrador.

Perthshire winters mean your solar contribution will be embarrassingly low November through January — the gasifier will carry the load whether you planned for it or not.