PowerChute/Back-UPS RS 800 reports bad AC voltage, but AC voltage is just fine. Is this a circuitry or battery problem?

[Anonymous user]

I have a Back-UPS RS 800 that we received in 2004.  We have replaced the battery in the past and the current battery is about 3 years old. 

Currently, this unit is repeatedly switching to battery for a fraction of a second, often many times in a single minute, but sometimes not for many minutes.  When I check the status in PowerChute, it reports that the UPS says that the the line AC voltage is varying wildly, high and low.  However, I have tested the line AC voltage and there is nothing wrong with it.  The AC voltage is rock-steady at 122 volts.

When I use PowerChute to run a battery Self_Test it says that the battery is bad.  However, when I test the UPS by simply unplugging it from the wall, then PowerChute accurately predicts that the battery will power the computer for about 10 minutes.  When I plug it back in after about 5 minutes, it still reports about 5 minutes of runtime remaining .  So, in terms of runtime, the battery is working just fine.

The UPS has also occasionally freaked out and cut off power the computer a few times in the last few weeks.  The unit is not overloaded and only has one computer and dual-monitors connected.  It has powered this same computer and monitors for many years.

So the question here is symptoms.  The UPS/PowerChute report bad AC line voltage when the voltage is just fine.  AND the UPS/PowerChute report that the 3-year-old battery is bad, but the battery still has plenty of runtime left.  AND the UPS is cutting power sporadically.

Questions:

Is this a circuitry problem in the UPS or can a battery cause this symptoms? 

Is it just time to replace this UPS?

[BillP · Accepted solution]

Hi,

Since the UPS is 9 years old and the battery is 3 years old I suggest replacing the unit. You can take advantage of the Trade UPS program where you trade in your old UPS and receive a discount on a new one.