Anyone else using their EV as emergency home backup when the grid goes down?

Ran my Kangoo ZE through a Victron MultiPlus last winter during that 6-hour outage and kept the fridge, router, and a few lights going no bother — think I pulled maybe 4kWh out of the 33kWh pack, barely tickled it.

V2H/V2L is still a mess in the UK legally and kit-wise, but honestly with a decent inverter and some creativity you can bodge something workable. Fogstar cells in a proper static bank would've been the "correct" answer but where's the fun in that when you've got 33kWh sat on the drive?

Curious whether anyone's done this more formally — proper V2L adapter, scheduled Octopus Agile charging so the car's always topped up before storm season, that sort of thing? Or are we all just running jump leads to an inverter and hoping for the best?

NickEvans | 47 posts

@KangooBuild nice one, that's a tidy setup. The Victron MultiPlus is doing a lot of heavy lifting there — did you have to fiddle with the charge current settings to stop it getting confused about the SOC, or did it play nicely with the Kangoo's onboard charger?

I've been half-tempted to try something similar with my Leaf using a CHAdeMO-to-AC inverter, though the second-gen battery degradation on mine makes me a bit cautious about how deep I'd want to discharge it in anger.

4kWh out of 33 is sensible — you're barely scratching the surface really. The tricky bit for most people is the connection side of things; what are you using for the AC coupling, a proper changeover switch or something more involved?

Great thread this. @KangooBuild that's exactly the kind of resilience thinking I've been pushing on here for ages — EVs are basically massive LiFePO4 banks on wheels that most people ignore.

Worth flagging for anyone considering this: battery chemistry matters enormously for discharge depth. NMC packs (like the Kangoo ZE) don't love being pulled below ~20% repeatedly — that 4kWh from 33kWh is sensible restraint. LFP-based EVs like the MG5 or newer BYD models are considerably more tolerant of deeper cycling.

On my boat I run a dedicated Victron/Fogstar setup, but honestly for home backup the V2H potential sitting on most driveways is extraordinary. The limiting factor in the UK right now is proper bidirectional charging infrastructure — OBD-side solutions exist but they're still fiddly compared to what Japan's had for a decade with CHAdeMO.

EllaDixon71 | 134 posts

Love seeing this in practice @KangooBuild — only pulling 4kWh from a 33kWh pack is brilliant, barely a dent really. I've been eyeing up a similar setup using our Zoe but the V2H situation in the UK is still a bit of a faff compared to what they've got going in Japan and the Netherlands.

One thing worth flagging for anyone looking to replicate this — check your EV warranty small print first. Some manufacturers are still funny about deep discharge cycles outside their approved use cases, even if the actual capacity draw is modest. Might be worth documenting what you pulled and when, just to cover yourself.

@WelshCamper agree it's solid resilience thinking — pairs nicely with even a modest solar setup to top the pack back up afterwards.