Back-UPS NS 1050 Overload alarm with nothing pluged in

[Anonymous user]

I have a Back-UPS NS 1050 unit that is about 3 years old. I had two computers and one monitor plugged into the unit, and it worked fine for over a year. Since neither computer uses a lot of power, this seemed like a fine solution. Total power draw was slightly less than half of the total power output capability. About a week ago, the other computer would turn off whenever I switch the other computer on. Now, the overload light has come on, with the solid beep alarm (continuous tone). I removed all of the equipment plugged into the unit, restarted the unit, and the overload alarm still comes back on. I tried pressing the circuit breaker switch at the back of the unit, but it seems to be all the way in, so I don't think that ever tripped. The PowerChute software reports that the current load on battery backup is 0 watts (nothing is currently plugged in).

The unit looks identical to the Back-UPS 1200VA.
http://www.apc.com/resource/include/techspec_index.cfm?base_sku=BR1200&total_watts=200

It is a tall thin white box with the battery located at the bottom front of the unit. I disconnected and removed the battery to check out which type it is, and as far as I can tell, it is a RBC32 battery. I purchased this unit from Costco about three years ago, so I think it is a special model made for the big box retailers. I cannot find the unit listed at the APC website.

Is this a problem that can be fixed by replacing the battery? I don't know if something else is wrong with the unit, since the "Overload" light is on, but the "Replace Battery" light has not turned on. Once again, there is nothing plugged into the back of the unit, but the overload light comes on and the unit emits a continuous tone. If it fix is to just replace the battery, then I would prefer to do that. However, I am a little worried about replacing the battery and still being stuck with a dead unit.

[TheNotoriousKMP_apc · Accepted solution]

SM,

In this instance, do not replace the battery. It's possible that the load sensor within the UPS has failed, or another electrical component that controls that feature has failed. To test for sure:

1. Unplug the UPS from the wall (make sure the UPS is off).
2. Depress the Power Button.
3. You will get an initail beep (similar to what you would get when normally powering it off), continue to hold the Power buttom.
4. Release the Power Button DURING the second longer beep, and that will force the UPS on battery.

If the UPS immediately goes into Overload, there's a problem with the UPS that no RBC will fix.

[Anonymous user · Accepted solution]

I tried what you suggested. With the unit unplugged, I pressed the power button until I heard the longer beep, then let go. The unit went to overload condition. This is with nothing plugged into the unit. Does this mean that my unit is bad and I will need to buy a new one? Well, at least I didn't waste $90 on a new battery that would not fix the problem.

[TheNotoriousKMP_apc · Accepted solution]

SM,

While it's great that we were able to stop the unnecessary purchase of an RBC, unfortunately the UPS has faulted and will need to be replaced. I can recommend two options, as always, there are others as well.

1. APC Refurb Site: http://buy.apc.com/commerce/storefronts/factoryoutlet/default.aspx
2. APC Trade-UPS: http://buy.apc.com/commerce/storefronts/tradeups/tradein.aspx?storefrontcode=apcetu&countrycode=US&t...

[Anonymous user]

I was playing around with the unit. When I removed the battery and tried the test again, the "Replace Battery" light would come on, not the "Overload" light. When I plugged the battery back in, the "Overload" light would come on. Does this make a difference?

[TheNotoriousKMP_apc · Accepted solution]

I think the battery connection takes precedence over everything else - so that it won't report basically anything unless you eliminate the flashing Replace Battery indicating to connect the battery/check its connections.