BACK-UPS ES 550VA does not go to battery when power is lost.

[Anonymous user]

For some reason if power is lost my 550G-CN backup does not go to battery power. instead the computer shuts down instantly instead of the 4 minutes its supposed to last according to the powerchute program. Powerchute shows the battery is charged to 91%. Is this battery back toast?

[Anonymous user]

An immediate shutdown of the load attached to your UPS usually indicates a weak or worn out battery. If the unit is more than 3-5 years old, the battery is probably worn out.

You can replace the battery yourself if you wish to do so, it's quite safe and easy. A door on the underside of the unit slides open to reveal it. A really old battery might be somewhat swollen, in which case you might have to tap the unit to get it out. APC sells replacement batteries with warranty coverage or you can use a generic replacement (12V, 7 through 9AH) at your own risk.

If you decide to replace the entire UPS, I would recommend a larger capacity model. Four minutes may not be enough time if anything stalls or pauses when the computer shuts down, and that time will only decline as the battery wears out.

[Anonymous user · Accepted solution]

Last year, our company purchased over 100 of these units to protect the PC's in two call centers.  Both call centers have backup diesel generators that will restore power within 5-10 seconds of a power failure, so we expected these APC units to keep the computers on until generator power kicked in. We don't have these backups overloaded, each has one small PC and two flat screen monitors plugged into them.

Between our two call centers, we've had a couple of power outages over this last year. The reports that started coming in were rows of computers suddenly losing power. I came to these forums today to see if anyone else was having issues with this model. We did some tests by walking down the rows and unplugging the APC from the wall and the APC does it's job and keeps the PC powered up.

I could see one or two units being bad, but not banks of them. I opened a ticket with APC and will update this post when/if i hear from them.

Denny