FOX-ESS-SP Whole Home Gateway Test
For anyone considering this add-on and how it may perform, I tested it today - it switched over within a second but everything in the house did reset. Nothing survived the drop, such as PC, Router, etc.
Personally, I did expect this and knew it was likely the case when I had it installed - my goal is to get everything in the house back running on battery power ASAP if a cut occurs - not a full UPS.
A friend of mine a mile away had a 9hr power cut last week so it can happen and it only needs to happen 1 or 2 times in the next 10 years to make it worth it for me.
So yes - probably a 1 second or so drop - then a further 1 second when it auto-reconnects to grid. Box is directly next to mains box - about 4-5m of wiring from consumer.
For me its definitely worth it to have the peace of mind.
Hope this helps.