Anyone else running a garden office purely on solar through a UK winter? How are you managing?

Set up my garden office last spring with a 400W panel on the roof (south-facing, about 15° pitch because of the felt roof) feeding into a 200Ah lithium battery via a Victron 100/20 MPPT. Works an absolute treat from April through to October — barely gives it a second thought. But now we're into November and I'm starting to feel the pinch. Yesterday I got a grand total of 0.4 kWh from the panel. The office has a small infrared heater, a monitor, laptop, and a little lamp. That heater alone is 600W.

I'm currently supplementing with a 240V hook-up from the house on the really grim days, which feels like cheating a bit, but I can't see how to avoid it without going to a completely silly battery size. I've got a Duracell portable power station as a backup as well, which I charge indoors overnight when it looks like it'll be a clousy one. Not exactly elegant.

Wondering if anyone's cracked this properly — either by massively oversizing the panels, adding a small wind turbine, or just accepting that December and January are grid months. Is there a realistic all-solar solution for a UK winter office, or is some form of top-up just the sensible answer? Keen to hear what setups people are actually running.

@WrongFuse99 that 15° pitch is going to hurt you badly come November. I learned this the hard way with my static caravan setup — swapped to a steeper ground-mount frame over winter (around 45°) and the difference in December harvest was genuinely shocking. Low sun angle in the UK means you're basically pointing panels at the horizon otherwise.

200Ah is also going to feel very tight once you're only pulling 30–40% of rated panel output on grey days. I run a Fogstar 280Ah alongside mine now specifically for the 3-day no-sun stretches we get.

Worth setting a minimum SOC alarm on your Victron — saved my battery more than once when I'd forgotten to check.

@WrongFuse99 yeah 15° is rough in winter - you're basically losing a massive chunk of generation when the sun's already barely there.

Running a similar setup here (500W, Fogstar 200Ah lithium, Midlands) and honestly December/January are brutal. A few things that've helped me:

• Tilt frame to boost the angle seasonally - even getting to 50-60° makes a real difference
• Drop non-essential loads ruthlessly (I ditched the always-on monitor)
• Keep an eye on your Victron app daily, not weekly

Also worth checking what your actual overnight draw is - most people are surprised. A 200Ah bank sounds decent but if you're running a monitor, router, and any heating it disappears fast.

What's your typical daily consumption?

@WrongFuse99 the pitch issue has been well covered already, but one thing nobody's mentioned - have you looked at your actual consumption patterns? I found the biggest win in my garden office wasn't generation side at all, it was auditing what was drawing power. My monitor alone was pulling 80W constantly. Switched to a laptop-based setup and suddenly my 100Ah battery was lasting nearly twice as long through grey December days. Worth logging everything with a decent energy monitor before winter properly bites. What are you actually running in there - heating, monitors, desktop? That'll really determine whether your 200Ah is going to see you through or whether you need to think about a backup strategy for the genuinely grim weeks. ☁️

GazBrown72 | 847 posts | ⚡ Solar Enthusiast

@WrongFuse99 good setup to start with, and the others are right about the pitch but I'll leave that there. What I'd add - have a proper look at your actual consumption. Running a garden office through winter is mostly won or lost on the load side, not just generation. I swapped my old monitor for an efficient one, ditched the electric radiator entirely for a well-insulated space plus a small oil-filled rad on a timer, and my daily draw dropped dramatically. Also worth checking what's pulling phantom loads overnight - my router alone was costing me 15-20Ah doing nothing useful. Victron's app will show you exactly where it's going. Sort the consumption first, then worry about adding panels. What are you actually running in there day-to-day?

Running a narrowboat through four winters taught me that the problem isn't usually generation — it's the invisible loads you forget about. Standby power on monitors, routers ticking away overnight, a laptop charger drawing phantom watts constantly.

Before adding panels or tilting anything, I'd spend a week with a plug-in energy monitor on every single device in that office. My cabin setup revealed I was burning nearly 15Ah a day on things I thought were "off."

On a 200Ah bank you've likely got less usable capacity than you think too — what's the actual battery? If it's not a proper LiFePO4 (Fogstar Drift or similar) the real-world figures can be quite different from the label.

Sort the consumption side first, then reassess what the generation side actually needs to cover.

CotswoldSolar | 1,203 posts | ☀️ Solar Evangelist

@WrongFuse99 worth adding to what @JX_Boats said about invisible loads — grab yourself a Shelly plug or similar smart monitor on anything you think is "off." My laser printer was drawing 4W constantly in standby, which across a December day was eating a meaningful chunk of what my panels were actually generating. Also, have you set your MPPT absorption and float voltages correctly for your specific lithium chemistry? Factory defaults are sometimes a bit off and can leave your battery consistently undercharged without you realising. What brand are the cells? That 15° pitch genuinely hurts in winter but it's not fatal — I'm managing fine in the Cotswolds on similar geometry.