What's everyone's go-to setup for keeping the van powered during a multi-day grid outage at home?

So this came up for real last winter — three days without mains after a substation fault knocked out half our street. I'd been sleeping in the van anyway during a conversion job, and it suddenly became the neighbourhood power station. Ran a 40L compressor fridge, phone charging, and a small fan heater off my 200Ah Fogstar Drift lithium for the better part of two days before I started getting nervous about state of charge.

The thing is, I had 400W of Renogy panels on the roof but it was January in the Midlands — you can guess how much I was actually harvesting. Think I squeezed maybe 80–90Wh on a good day. My Victron SmartSolar kept the stats honest but they weren't pretty. The fan heater was the obvious culprit and I binned it after day one, switching to blankets and a gas burner for warmth.

What I'm wondering now is whether it's worth wiring in a proper shore power hookup so the van battery can also charge from the house when the house has power — essentially making it a bidirectional backup buffer. Has anyone done this with a Victron Multiplus or similar? Curious what the install looked like and whether it actually passed any kind of inspection.

JakeShaw96 | 847 posts | ⚡ Solar Enthusiast

Proper timing on this thread @VitoBuild — similar situation hit us last February, about 36 hours without power.

What saved us was running a decent extension lead from the van's leisure battery bank into the house for the essentials — phone charging, a 12v camping lamp, and keeping the router ticking over (amazingly that kept signal going when neighbours had nothing).

The key thing I'd add that nobody mentions: keep your van plugged into shore power whenever you're at home normally, so your batteries are always topped up before an outage hits. Sounds obvious but I wasn't doing it until that incident.

Since then I've also fitted a basic 200w solar panel on the roof specifically so the van can sustain itself and the house simultaneously during a prolonged outage without needing to run the engine.

ExpertLife | 2,341 posts | 🔋 Off-Grid Veteran

Good thread this. One thing worth mentioning that gets overlooked — if you're running the van as your primary backup during a prolonged outage, keep a close eye on your leisure battery state of charge before you even think about starting the engine to top things up. Deeply discharging and then shock-charging repeatedly is a reliable way to kill a battery bank faster than almost anything else.

I'd strongly recommend a decent battery monitor (Victron BMV series is hard to beat) so you're making informed decisions rather than guessing. Knowing your actual capacity remaining changes everything when you're rationing power across multiple days. @JakeShaw96 what battery chemistry are you running? That'll affect your strategy quite a bit.

MarkBennett | 1,203 posts | 🔋 Off-Grid Veteran

Worth thinking about your inverter's transfer switch capability here. My shepherd's hut runs a Victron MultiPlus-II which handles this elegantly — the moment grid drops, it switches to battery in under 20ms, transparent to anything connected. Same unit handles shore power top-up when grid returns.

For the van specifically, if you're running a Victron inverter/charger, the VE.Bus Smart Dongle gives you remote monitoring so you know exactly where your SOC sits without trudging outside at 2am.

The weak point most people overlook is cable runs between van and house — a decent 10mm² extension with proper weatherproof connectors rather than a daisy-chain of 13A extensions. Fogstar Drift cells in my hut's bank have held up through two winters without complaint.