Having very high winds today, and the power is glitching. Unfortunately, my UPS takes over, beeps about twice per second, and 10 seconds later shuts down the output. However, the "replace battery" LED is not lit up, so I don't know whether it's just the battery, or something wrong with the charging or conversion. Is there any way to tell, short of replacing the battery to see if that fixes it? I'm a hobbyist, so don't have much gear. Would measuring the battery voltage when it's been "charging" overnight tell me anything? Or is it just time to replace the whole thing? It must be close to 10 years old. I know the batteries die over time, but do the innards die as well? The UPS almost never has to kick in for an extended period - maybe once a year. So it's usually just sitting there trickle charging. Anyway, is there any reasonable way to identify the problem?