Anyone else running a separate solar setup for a garden office rather than tying into the house?

Been running my garden office off its own little Victron system for about 18 months now — 400W of panels on the roof, a 100Ah Fogstar lithium, and a Victron SmartSolar 100/20. Totally standalone, never bothered trying to connect it back to the house grid. Works a treat for a laptop, monitor, a few LED lights and the occasional kettle boil (though that last one does give the Cerbo a minor heart attack).

The reason I kept it separate was simplicity — no DNO notification faff, no G98/G99 headaches, just a self-contained 12V system that looks after itself. Battery sits between 80–95% most mornings even in January, which surprised me. South-facing roof helps obviously.

Now I'm turning my attention to a shepherd's hut in the back field and wondering whether to keep the same philosophy — totally standalone — or whether there's any actual benefit in linking the two buildings somehow. The hut will probably need 24V rather than 12V given I want to run a small 240V inverter for it. Has anyone done a two-building off-grid setup and is it worth the extra complexity, or just run two separate systems?

@LesPhillips that's almost exactly what I've been considering for my static caravan setup but keep going back and forth on whether standalone makes more sense than tying into the house consumer unit.

Few questions if you don't mind:

• How are you finding the 100Ah Fogstar in winter? Worried about a single battery being undersized for shorter days
• Did you need building regs/permitted development sign-off for the panels on the office roof?
• Are you running any heating off it or purely lights/screens/router type loads?

I've been looking at a similar Victron SmartSolar setup but was tempted to go 200Ah given my caravan already pulls more than a typical office would. The standalone approach does appeal — no messing about with the house wiring and the DNO.

Hey @LesPhillips, yes! Running almost the same setup here but for a converted shed workshop. Been going about two years and honestly it's one of the best decisions I made — keeps the energy usage completely separate which makes accounting much simpler if you're running a business from the office.

@SueJohnson the static caravan application is probably even more straightforward than a garden office since your loads are generally more predictable. Only thing I'd say is think carefully about winter usage before committing to battery size — I slightly underspecced mine initially and had a few gloomy January weeks where I was being a bit more careful than I'd have liked. Bumped up to 200Ah and haven't looked back since.

Really glad to see this thread — I've been doing something similar for my boat workshop at the bottom of the garden for about a year now. The beauty of keeping it separate is that any issues stay isolated from the house system entirely. One thing worth mentioning to @SueJohnson and @LesPhillips — if you're running any sensitive electronics in there (monitors, laptops etc.), it's worth double-checking your inverter output quality. I added a small Victron MultiPlus rather than a basic inverter and the difference was noticeable. Also @DougDixon56, have you found winter performance a challenge? I topped my setup up to 600W of panels after the first winter when I realised 400W wasn't quite cutting it through December and January up here in Scotland.

Great to see so many of us going the standalone route! @LesPhillips, the Fogstar/Victron combo is a solid choice — I went a similar direction for my greenhouse setup about a year ago. One thing worth mentioning that nobody's touched on yet: if you're running any meaningful loads through winter, it's worth keeping an eye on your battery's state of charge during those short grey days. I found adding a small secondary panel on a south-facing wall made a noticeable difference in December and January when the roof panels were getting barely anything. @SueJohnson, for a static caravan it could actually work out even better value since you've likely got more roof real estate to play with. The independence from the house supply is genuinely brilliant — no worrying about cable runs or distribution boards.

Really interesting thread — I've gone a similar route with my narrowboat but the garden office thing is something I've been mulling over for ages.

One thing nobody's mentioned yet: VRM portal integration even on a standalone setup is absolutely worth doing. Even if it's not tied to your house system, having remote monitoring via the Victron app means you're not constantly trudging outside to check state of charge. Saved me more than once when I'd left something drawing overnight.

Also worth considering a small Cerbo GX if you ever think you might want to expand — @LesPhillips, 400W and 100Ah is fine now but you'd be amazed how quickly you start plugging more things in once you've got reliable off-grid power sitting there. Ask me how I know 😅

The Fogstar cells seem to be holding up well across the board too, good to hear.