We have a pair of uninterruptible power supplies (UPS) on the property. Both are somewhat vintage models from Belkin. A 1000 VA model (F6C1000) in my office rack powers our network core. A smaller, 900 VA model (F6C900) in a central closet, powers those network components that live in the house. Both of them have been misbehaved in recent weeks. At this very moment they are basically non-functional.
I’ve long believed that the network core should survive minor power line irregularities. This belief stemmed in part from our migration to IP-based telephones for home & office. Our phone service should survive a power line bump. With both UPS in their fault-riddled state a loss of line power, even just a power line switching bump, caused our entire network to go down. This situation eventually had to be addressed.
The sealed batteries is consumer UPS such as ours have a fixed lifespan. At a certain point they simply cannot retain a charge, and the device throws an error. From that point onward they become nothing more than an overweight outlet strip.