Gill Passman wrote:

Yes, a UPS has a limited life span.....just so long as the battery in
side lasts....if you are talking a long power outage then it wouldn't be
much use (I'm talking days not a couple of hours) - but as the first
line of defense then it would be a good starter....

I bought one that, according to its watt hour rating, should have powered a
couple of heaters and filters for two hours or more. I turned off the
circuit it was protecting to replace a receptacle and the UPS died after only
half an hour.

When I called the manufacturer (a major UPS maker) to question this I was told
that was normal, it would put out the rated capacity for half an hour, or it
would put out less for half an hour - that's just the way it worked.

Needless to say, I'm not impressed by a UPS for anything other than to let my
computer shut down gracefully.

--
It's turtles, all the way down