Has anyone actually tested their backup power setup during a real grid outage — what held up and what didn't?

We had a nasty one last Tuesday — nearly 11 hours without power here in rural Shropshire after storm damage to the lines. I'd always assumed my setup was solid: a 200Ah LiFePO4 leisure battery, a Victron SmartSolar 100/30 keeping it topped up, and a Renogy 200W panel on the garage roof. In theory, plenty of headroom. In practice, I found out pretty quickly what I hadn't thought through.

The solar kept ticking along fine and the battery held up well for lighting and phone charging. Where it fell apart was the fridge — I've got a small 12V compressor fridge that I'd half-forgotten draws around 4-5A when the compressor kicks in. After about 7 hours I was watching the battery voltage more nervously than I'd like to admit. Also completely forgot I'd never actually wired the setup to the house circuit properly, so I was running extension leads all over the kitchen like some kind of mad science experiment.

Has anyone else had that "real world vs. theoretical" moment with their backup kit? Specifically curious whether anyone's added an automatic transfer switch to properly integrate their off-grid battery into the house, and whether it was straightforward to get something compliant with UK regs. I keep seeing ATS units online but I'm not sure what I actually need for a modest single-phase domestic setup.

@LizWalker 11 hours is a proper test. Had a similar scenario last winter with my static caravan setup.

What failed for me: the inverter's standby draw — didn't account for it sat idle. Chewed through roughly 8% capacity overnight doing nothing useful.

What held: Victron MultiPlus handled the transition seamlessly. Zero flicker on sensitive kit.

One thing people consistently underestimate — state of charge at the moment the grid drops. If you're sitting at 60% because you "meant to top it up," your 200Ah is suddenly a 120Ah battery.

Also worth checking: does your setup actually disconnect from grid properly during an outage, or are you just assuming it does? Learned that one the hard way. Physical transfer switch, not just software relays.

What inverter are you running?

@JulieEvans:

@LizWalker I know exactly what you mean about assumptions! We had a 7-hour outage back in February and my "sorted" setup revealed a few surprises. The battery and inverter performed brilliantly, but my downfall was the fridge — I'd completely underestimated the compressor startup surge. Tripped the inverter twice before I just switched it off and accepted losing the contents.

The other thing nobody tells you is how quickly you burn through capacity once the family realises the power's out and starts actually using things. My 14-year-old had the telly, phone charger and kettle all going within minutes!

Since then I've put a proper load list together and actually practiced running everything off-grid for a weekend. Genuinely recommend doing a planned drill before the next real outage catches you out.

@BurnShaun:

@LizWalker Ooh, 11 hours is a decent shakedown — sorry you had to find out the hard way though! We lost power for about 9 hours last autumn and the thing that caught me out wasn't the battery or inverter, it was the router. I'd completely forgotten it was still on mains and suddenly had no monitoring access to anything. Felt a bit daft standing there with a perfectly healthy system I couldn't check properly!

Ended up running a small TP-Link off a USB power bank as a temporary fix, but I've since wired the router directly into the 12V system. Also discovered my wife's electric blanket draws a surprising amount — learned to budget that in properly now. Sometimes you genuinely don't know what your weak points are until the grid does you the favour of disappearing! 😄