
I got by with just one down here until now, by plugging the modem and router in with my good PC and just sticking the old box in the surge only outlets (it's off most of the time anyway these days).
It was a 5 year old Cyberpower 1500VA AVR model, so old I bought it on Newegg (before I was buying from Amazon) so I guess I did well with it. It started out beeping with an error code on screen. Turning it off and on again reset it, and while the battery showed low capacity, once reset the battery seemed to charge to full. It happened again a few weeks later (self tests I presume) and reset. Unfortunately, while it was showing the battery full, the instant it went on battery (Saturday, when the power blinked) it shut right off.
I considered buying batteries, but that would be a waste of money if the electronics fail. $70'ish for batteries (a set of 2) + shipping for a 5 year old UPS... fuck that.
Anyway, I bought another one of these ("buy again"). Now I have 3 units of this same model in the house (one upstairs). They seem pretty good, and tolerate being on generator power.
CyberPower CP1500AVRLCD3 Intelligent LCD UPS System, 1500VA/900W, 12 Outlets, 2 USB Ports, AVR, Mini Tower, Black
https://www.amazon.ca/dp/B0BCMLLSHL