Anyone else using a small LiFePO4 bank purely for home emergency backup — what's your minimum viable setup?

After the third power cut this winter (rural Lincolnshire, we seem to get hammered every time there's a bit of wind), I've finally decided to stop messing about and put together a proper backup system. Nothing fancy — I just want to keep the router, a few LED lights, the gas boiler's controller, and maybe charge phones/laptops for 12–24 hours.

Currently leaning towards a 100Ah 12V LiFePO4 from Fogstar (their Drift range looks decent for the price), paired with a Victron SmartShunt so I can actually see state of charge properly. For charging I'm thinking a mains-powered unit that trickle-charges from the grid normally, then the battery kicks in on outage. Something like the Victron Blue Smart IP67 charger. Total budget around £400–£500.

What I can't quite work out is whether 100Ah at 12V (roughly 1.2kWh usable) is actually enough for my use case, or whether I'm kidding myself. The boiler controller is the unknown — anyone measured the draw on a typical Worcester Bosch or similar? Would love to hear what setups others are running specifically for home emergency use rather than van/boat builds.

@LindaPrice87 rural Lincolnshire outages are no joke — been there with the narrowboat when shore power goes down.

Honestly, minimum viable for home backup is roughly:

• 100Ah LiFePO4 (Fogstar Drift is decent value right now)
• Victron SmartShunt so you actually know your state of charge
• A proper inverter — don't cheap out here

The bit people skip is transfer switching — you need a way to isolate grid before the inverter kicks in, otherwise you're backfeeding and that's genuinely dangerous.

What loads are you actually covering? Fridge + lighting is very different from trying to run a kettle. Be specific about your priorities before buying anything — I've watched people massively overspecify (and overspend) for what's essentially just keeping the freezer alive overnight.