Anyone else using a small wind turbine alongside solar on a cabin setup? Struggling to balance the two

I've been running my 12V cabin system for about 18 months now on a pair of 200W panels with a Victron 75/15 MPPT, feeding into two 100Ah AGM batteries. Works a treat in summer but as soon as October hits I'm basically rationing power — cloudy weeks in the Lake District mean the panels are doing almost nothing some days, genuinely getting 10-20W on a bad overcast afternoon.

So I've been looking at adding a small wind turbine to cover the winter gap. Been eyeing up the Rutland 914i — it's rated at 150W nominal but from what I've read it rarely hits that in real conditions. My average wind speed up here is probably 4-5 m/s, which apparently puts it more in the 30-50W range realistically. Not massive, but even that would make a big difference overnight and on grey days.

The bit I'm confused about is how to combine it cleanly with the existing solar setup. Some people say you need a separate wind charge controller and then just let both feed the battery bank independently. Others reckon you can use a hybrid controller that handles both inputs together. Has anyone actually done this in practice? Worried about the two controllers fighting each other or overcharging the batteries.

Has anyone got a working setup combining wind and solar on a similar scale? Curious what controllers you're using and whether the Rutland is actually worth the money or if there's something better for the price.

Hey @Gazza99, welcome to the October struggle! I went through exactly this last year with my Welsh hillside setup. The key thing I found was keeping the wind and solar inputs separate rather than trying to combine them into the same controller. I'm running a dedicated wind charge controller for my 400W turbine that feeds into the battery bank independently, while the Victron handles just the solar side. That way each source manages its own charging curve properly.

One thing worth checking - what wind controller are you currently using? Some of the cheaper ones dump excess energy as heat through a resistor load, which is fine, but you need to make sure it's rated correctly for your battery bank voltage or you'll confuse the Victron's voltage readings something rotten.

What's your typical winter consumption like? That'll help figure out whether the turbine sizing is right for your needs.

Running a small 400W turbine on my shepherd's hut setup alongside 300W of solar. The key thing nobody tells you is you really need a dedicated charge controller for each source — don't try combining them before the controller.

I use a separate dump load controller for the turbine feeding into the same battery bank. Victron handles the solar side, cheap-ish wind controller handles the turbine, both talking to the same 200Ah Fogstar lithium bank.

October through February the turbine genuinely pulls its weight when the panels are sitting there doing nowt in the gloom.

What wind controller are you running @Gazza99? That's usually where people trip up — mismatched dump loads causing grief with AGMs especially.

Great thread @Gazza99. One thing worth flagging that catches people out — when you introduce a turbine to an existing solar setup, your charge controller situation gets more complicated than just adding a second unit. The turbine needs its own dedicated controller with dump load capability, because unlike solar you can't simply disconnect a spinning turbine without damaging it. The excess charge has to go somewhere — usually a resistive dump load like a water heater element.

@PaddyDixon61 is right that there's more to it than people realise. I'd also suggest looking at your battery bank capacity before anything else. Two 100Ah AGMs might become your real bottleneck once you've got both sources pushing charge in during a stormy autumn day. You could be cooking batteries without realising it.

What turbine are you considering? That'll shape the advice considerably.

Great timing on this thread, @Gazza99 — October is exactly when wind starts earning its keep.

Something worth adding to what @KeithMartin and @PaddyDixon61 have touched on: if you're going down the turbine route, seriously consider whether your existing Victron 75/15 can handle the combined input. At 12V you're already fairly close to the ceiling with 400W of solar, so adding wind without reassessing your charge controller setup could leave you with charging conflicts or worse.

Also worth thinking about battery capacity — two 100Ah AGMs will fill quickly once you've got wind supplementing solar on a decent autumn day, and an overfull AGM isn't happy. Might be worth looking at either upgrading bank size or adding a dump load diversion for the turbine output specifically. A simple water heating element dump works a treat and nothing goes to waste.

@Gazza99 one thing I'd add to what @KeithMartin is hinting at — you'll want a dedicated dump load controller for the turbine side, completely separate from your MPPT. Turbines cannot be simply disconnected the way solar can; a stall or open-circuit situation will destroy the unit. I run a Marlec controller with a water heating element as the dump load in my shepherd's hut, and it's been rock solid through two winters now.

On the balancing side specifically — the two charge sources will effectively fight each other if they're both trying to bulk-charge simultaneously into a near-full battery. Worth staggering your absorption setpoints slightly, or letting the turbine controller handle regulation independently whilst your Victron manages the solar side. The Victron forums have a decent thread on this exact scenario if you dig through the archive.

Hey @Gazza99, good shout on adding wind for the winter months. One thing nobody's mentioned yet — cable run length from the turbine really matters at 12V. Even a short voltage drop can make your readings look healthier than they are and confuse the charge controllers. If your turbine's more than about 10 metres from the batteries, seriously consider upsizing your cable gauge or even bumping the whole system to 24V. I made that mistake first time round and couldn't work out why my batteries were chronically undercharged all December. Worth measuring your actual voltage at the battery terminals under load before anything else. 👍

Really interesting thread — I've been weighing up exactly this for my setup (similar to yours @Gazza99, Victron MPPT into two 100Ah batteries).

Quick question though: does anyone know whether the Victron MPPT will actually see both inputs cleanly if you wire solar and wind through separate controllers into the same battery bank? Or does the MPPT get confused by the turbine controller also pushing current in?

Also — what sort of wind turbine wattage are people pairing with a 400W solar array? Feels like oversizing the turbine could cause more headaches than it solves, especially if the dump load is firing constantly during stormy nights when the batteries are already full.

Is there a rough rule of thumb for matching turbine output to your existing solar capacity?