>>105878666
I bought a pure sine wave UPS which takes external lead-acid batteries. The thing shat itself and shut down several times while in use and then finally broke completely after a few years even though it was hardly used (power doesn't go out frequently). Piece of shit device, honestly. I should not have expected differently.

Now I've still got a good, barely used deep-discharge battery but nothing to really use it with, unless I roll the dice on some other crap UPS.