Why would you need it to last 3 days?

I reject your premise.

My APC (BN1500M2) just failed after less than a year. They are replacing it, but it’s definitely a pain.

The most annoying this was that the devices attached to it were losing power when the unit crashed, even though I wasn’t losing power on site. So it was failing at keeping continuous power being fed from the outlet. I was upset it failed after less than a year, buy I was really pissed my NAS was crashing when it was having problems.

I kind of wished I got a CyberPower.