Has anyone run a garden office purely on solar through a British winter? Sharing my setup and asking for advice

So I've been running my 6x4m garden office on solar since April and it's been brilliant through spring and summer — barely had to think about it. I've got two 200W panels on a south-facing roof, a 200Ah lithium battery (a Fogstar Drift), and a Victron SmartSolar MPPT 75/15 controller. Powering a laptop, a couple of monitors, LED lighting, and a small fan heater on its lowest setting occasionally. Total daily draw is probably around 400-600Wh on a typical working day.

Now October's hit and I'm already noticing the difference. Yesterday I only pulled in about 280Wh from the panels despite it being a mostly dry day — just weak, low sun. I've got a 230V hookup from the house I can fall back on, but I'd really like to avoid relying on it too heavily. I work from the office Monday to Friday, 8-9 hours a day, so there's no flexibility on usage really.

Has anyone actually managed to get through November to February without constantly topping up from the mains? I'm wondering whether it's worth adding a third panel, bumping up battery capacity, or just accepting that winter means grid backup. Would love to hear from people who've genuinely tried it rather than just the theoretical numbers — especially if you're in the north of England or Scotland where I imagine it's even grimmer.

Hey @LisaHunt, great setup to start with! The honest answer is yes, but winter is a completely different beast. Your 400W of panels will be producing a fraction of their rated output on a grey December day — realistically you might see 30-50W on a proper overcast day. The short days make it worse too, obviously.

The big question for winter survival is what's your battery capacity and what are your actual loads? Heating is usually the killer — even a small 500W oil-filled radiator will drain a modest battery bank surprisingly fast.

I'd strongly recommend getting a smart plug with energy monitoring on everything in the office now, before winter hits, so you know exactly what you're dealing with. The numbers might surprise you!

What battery bank are you running currently?

Really useful thread this. @LisaHunt I'd echo what @PhilFox99 is saying about winter being tough, but one thing worth mentioning that often gets overlooked is panel angle. Most people set their panels at a shallow pitch for aesthetics, but tilting them steeper (around 60-70 degrees) for winter genuinely makes a meaningful difference — the sun sits so low in the sky from November through January that you can pick up noticeably more generation.

Also worth checking whether any neighbouring trees or fences are casting shadows that weren't an issue in summer but will creep in once the sun tracks lower.

What's your current battery capacity? That's often the real limiting factor through those gloomy December weeks rather than the panels themselves. A cloudy fortnight in January can drain storage pretty ruthlessly even if the office is relatively light on consumption.

Really timely thread for me as I'm just heading into my second winter doing exactly this in the Lake District — so not the sunniest spot! One thing nobody's mentioned yet: panel angle matters massively in winter. The sun sits so low in the sky that even a small adjustment can make a noticeable difference to your harvest. I knocked mine up to about 55° in October and gained a useful extra 20-30 minutes of decent generation daily. Also worth keeping an eye on shading from bare deciduous trees — surprisingly they still cast shadow even without leaves. @LisaHunt what battery capacity are you working with? That'll largely determine whether you'll struggle on those proper grey December weeks where generation is genuinely pitiful up here.

@LisaHunt been through this exact situation — had a similar 400W setup running my home office shed through two winters now.

The thing nobody mentions is panel angle. I knocked mine up from about 15° to 35° for winter, and the difference in those low sun-angle days was genuinely surprising. Takes twenty minutes with adjustable brackets.

Also worth knowing: a 100Ah battery isn't giving you 100Ah in November. Cold temps hit capacity hard. My Fogstar lithium handles it better than my old AGM ever did, but you still notice it.

The real test comes in that brutal December–January window when you get three consecutive grey days. That's when I learned to keep a small backup plan — even just a 13A socket run from the house as an emergency top-up rather than a primary source.