Anyone else running a garden office on solar + battery — how are you sizing it in winter?

Finally got my garden office sorted last summer and it's been brilliant running it off a 400W panel setup with a 200Ah LiFePO4 (Fogstar Drift). No complaints June through September — panels were generating way more than I needed running a monitor, laptop, and a small desk lamp.

Now the days are getting shorter I'm genuinely struggling. I'm in the East Midlands and some days I'm getting barely 0.5–0.8kWh out of those panels. The office pulls around 150–200Wh/day in mild weather, but I've just added a small 500W convector heater and that's a completely different conversation — even running it 2 hours a day is wrecking the battery before lunchtime.

Thinking about adding a second 200Ah battery and maybe a 200W panel to the north-facing slope that at least catches some low winter sun. Has anyone actually done the maths on whether that's worth it, or is a small generator as a backup charging source the more realistic answer for UK winters? Also wondering if a Victron SmartSolar with proper winter profiles makes a meaningful difference to what I'm actually harvesting.

@GoldenMechanic the summer honeymoon is real isn't it — then November arrives and suddenly you're doing the maths at 7am wondering if you'll make it through a grey Tuesday on Teams calls.

My cabin setup taught me the hard way that winter in the UK isn't just about fewer hours, it's about angle and cloud diffusion killing your actual yield. I ended up doubling my panel wattage before I touched the battery side — same Fogstar Drift 200Ah, just pushed more generation at it.

The thing nobody mentions: if you're running monitors, a laptop and a small heater occasionally, your December daily draw can be 3x what it was in July.

What's your heating solution? That's usually where garden office setups quietly collapse in winter.

@GoldenMechanic I'm in a similar boat — 600W of panels on my shed office and even that felt marginal through December and January up here in Yorkshire. The honest truth is you're probably looking at 1-2 usable hours of decent generation on a grey January day, so that 200Ah bank is doing most of the heavy lifting.

My advice would be to track your actual daily consumption first — a proper energy monitor like a Victron BMV tells you exactly what you're drawing. Most people are surprised how much a monitor, a couple of LED strips and laptop charger actually add up to.

Also worth checking your panel angle — I tilted mine steeper for winter and picked up a noticeable difference. @Slim3 is right though, November is when reality bites!