I have a small home networking and server setup and am in the process of looking for a UPS. The ones I’m looking at (around 1000-1500W) look like they’ll provide power for between 10 mins and an hour, depending on the power draw at the time. I understand that the point of the UPS is to provide power for long enough to enable a graceful shutdown.

I also have a 1kWh EcoFlow Delta 2 Portable Power Station. I use it for camping, but the rest of the time it’s sitting around doing nothing. You can plug an appliance into the EcoFlow’s AC output, and then plug the EcoFlow into the mains, and it will power the appliance continuously if the mains drops. Once the mains power returns, the EcoFlow will charge up again and the appliance continues to be powered. I’ve used it to keep a fridge powered when there was a planned power outage, and it worked well. However, I have read that the EcoFlow’s switchover time is around 30ms, which is probably too long to keep sensitive IT equipment online, so it can’t function alone as a UPS.

My question is: could I put an EcoFlow between the mains power and the UPS? This way when there’s a power cut, the EcoFlow will take over and continue to power the UPS (I think I’d get several hours out of it). Then when the EcoFlow dies, the UPS kicks in and at that point I can do a graceful shutdown. If power returns before the EcoFlow dies, then there would be no shutdown at all.

When I need to take the EcoFlow on holiday, I can just unplug the UPS from the EcoFlow and plug it straight into the mains without having to power everything off first.

It seems like a great idea, but my electrical knowledge is limited. Is there any reason that this wouldn’t work?