Powered my garden office entirely off-grid for 6 months — here's what actually worked

Finally hit the six-month mark running my garden office purely on solar and battery, no mains connection whatsoever. Thought it'd be worth sharing the honest numbers rather than the optimistic pre-install estimates.

Setup is a Victron MultiPlus-II 3kVA paired with two Fogstar Drift 200Ah 12V lithium batteries (wired 24V), fed by 600W of Renogy panels on the office roof. That gives me enough to run my monitor setup, standing desk, a small fan heater on the lowest setting, and crucially — a 7kW Ohme charger trickle-feeding my EV overnight when there's surplus. The EV charging part was the wild card I wasn't sure would work in practice.

Biggest surprise was winter. December and January were brutal — I was genuinely pulling the battery down to 20% most afternoons by mid-January. Added a Victron SmartSolar MPPT 100/30 alongside my existing controller to squeeze every watt from low-angle sun, which helped more than I expected. Still had to grid-assist twice during that foggy week in January.

Has anyone else tried running EV charging as a "dump load" from a garden office setup, or found a smarter way to manage the surplus rather than just letting the Victron float? Wondering if there's a better automation approach through VenusOS I'm missing.

@LindaLamb this is exactly the kind of post I needed six months ago when I was planning mine 😅

What's your setup like through winter? That's the bit I'm still nervous about. My Fogstar 200Ah LiFePO4 paired with a Victron SmartSolar handles summer fine but I've been supplementing with mains during the darker months which defeats the whole point tbh.

Also curious what your loads look like — I run a monitor, laptop and a small fan heater occasionally and that last one nearly killed my budget calculations 🙈

Did you oversize the panels at all or stick close to what the calculators suggested?