APC BE550G battery backup problem

[Anonymous user]

Hi, I recently got a APC BE550G to protect my computer from power outtages. It goes on to battery backup fine when I unplug it from the wall however my main source of power is a generator so I often run out of power and whenever this happens my apc switchs to battery backup but my computer still loses power before it does. I also have a external hard drive plugged into the apc and when this happens it does not lose power before the apc switch's to battery backup and it works fine. I thought maybe it was a falty unit and I exchanged it for a new one but I still have the same problem. I also Thought maybe The battery charge was just running out but every time I check it it says around 90 to 100 percent charged. Any Suggestions?

[BillP]

Did you change anything for the unit to operate on generator power? You'd probably need to change the sensitivity settings to allow the UPS to accept the generator power (it tends to fluctuate a lot, which a UPS doesn't like), though that also increases the length of the transfer time, which may be too long for your computer's power supply. It's a different power supply from your hard drive, which is probably more durable in terms of transfer time.

Also, it's not entirely relevant, but how is your main source of power a generator? Are you saying you don't have any utility power?

[Techie_apc]

Josha,

I would like to gather some more information from you to provide you ideas to fix this issue. Is the Computer plugged into the battery backup outlet? Could you please let us know the exact model number of the Computer? What is the estimated runtime showing on Power Chute software? Is the Computer rebooting or shutting down when this happens?

[Anonymous user]

Thx for the reply. The computer is a custom built one the same as this one -- http://cgi.ebay.com/AMD-QUAD-X4-PHENOM-II-955-AM3-COMPUTER-SYSTEM-PC-NEW_W0QQitemZ110498955959QQcmdZ...
The estimated battery time in powerchute is showing up as 14 minutes and the computer just completely loses power and does not reboot.

[Anonymous user]

Thx for replying. I had to change the sensitivity setting to low otherwise I would get a loud clicking sound every second. and yeah all my power comes from a generator and solar panels that charge some batterys. The thing I don't get about it not being able to switch over fast enough is whenever I manually stop power from going to it by unplugging it or turning of my power it works fine and my computer stays on. it just when my batterys shut off because theres not enough power in them that it my computer loses power.

[BillP · Accepted solution]

Does the UPS stay on during this whole process, or does it turn off along with your PC? What exactly happens when your batteries run out of power? Is the generator always on, or does it take a few minutes to kick on...?

My guess at this point is that, whatever happens when your batteries turn off, your computer's power supply doesn't like it.

The UPS could be switching between online & on battery a couple of times during this transition from battery to generator power, which probably makes your computer's power supply freak out. Multiple transfers, in addition to the longer transfer time required for use with the generator, is more difficult for your power supply to handle than a direct and single UPS transition from online to on battery, which you said it handles fine.

Also, the UPS you have is the one with the longest transfer time, so you'd likely have better results with a higher end UPS. It's possible all you'd need is a [Back-UPS RS|http://www.apc.com/products/family/index.cfm?id=23], though depending on conditions, you may need to go to a [Smart-UPS|http://www.apc.com/products/family/index.cfm?id=165] model.