We had a "good" brownout here this morning, and my UPS gave me only about ten minutes of life before everything just cut out on me. I had figured on more, and have received better in the past.

It has been sitting for six months unused and disconnected, only starting up again a couple of days ago.

Is there some way of testing it, other than just pulling the plug and timing until it quits?

Maybe it needs longer to fully charge than the couple of days it got?

I could run out and get another, but why if this one will continue to work for me.

Ideas of all kinds regarding it are welcome.

You could measure the battery voltage after a good time to charge. I suspect after sitting idle, the battery is in the first phase of dying. Not uncommon.

Do you have more load on it than before the last "test"? The run time is dependent on battery capacity and load, and age is the enemy.

Battery is dead, voltage reading will be normal but capacity in amp/h has decreased dramaticaly.

Battery is dead, voltage reading will be normal but capacity in amp/h has decreased dramaticaly.

Battery can't be dead if it ran a load for 10 minutes. Degraded, yes, dead, no.

Pretty much as previous posters have noted, battery is probably on it's last legs particularly if it's been left for a period without charge.

Testing is easy, charge it over night, put a known load of about 50% of rating and see how long it runs for. You should be able to find estimated run times on the manufacturer's web site.

Replacement batteries are readily available and will be significantly cheaper than buying a new unit.