Battery Malfunction

Morning all, I wanted to ask opinions on strange behaviour from my GE system yesterday.

I have AC3, 1x8.2 & 1x9.5. EPS is connected to cover whole house, apart from kitchen, in the event of a power cut.

Yesterday at 16.20 I lost power to the whole house, except the kitchen which continued as normal. At the time I was 20 minutes into a daily scheduled forced export managed by WonderWatt. There was no grid outage. WiFi was down as no power to the router so I couldn’t see any detail on the portal, or Apps.

The batteries are in a wooden enclosure, which stupidly doesn’t have doors so the front needs unscrewing to get access. I was preparing to do this when the power came back again, it was off for around 20 minutes.

I checked logs afterwards and there’s absolutely nothing reported, on the GE portal, or WonderWatt Activity logs.

I’d appreciate any theories as to what may have been the cause.

Thanks

Chris

How is the EPS to rest of house wired?
If kitchen is not on EPS and stayed on, it suggests not a grid failure.
Could there have been a momentary grid off/on that you did not notice, the AC3 went into EPS mode but was overloaded and tripped and then took time to reset?
I dont know what happens if EPS circuit is overloaded on an AC3. Does it trip, and then auto reset?

SteveCook Thanks for responding. Consumer Unit is partitioned into two, all the high draw items(Heat Pumps, EV Charger, Kitchen) separated from the rest and EPS is wired into the other side. It’s been like this since 2021.
My go to indicator for a grid outage is the Oven. The slightest blip and the clock defaults to midnight and flashes until you pay attention! This didn’t happen so I’m confident it’s battery related not grid.
I don’t know what happens if the EPS is overloaded. I had just turned the TV on when it happened so possible power surge caused it to trip out, although no indication in the CU.
Another odd thing is that when I look at my half hourly energy usage on Octopus there was zero during the period, so the battery continued to supply the non EPS side, fridge & freezer would have been on.
It does point to an EPS issue doesn’t it?