APC-SC1000 on line/on battery cycling

[Anonymous user]

I have an APC-SC1000 that I purchased in 2010 and haven't had any problems with it until about 2 weeks ago.  It started switching from on line to on battery three or four times in a row with anywhere from one to five beeps with each switch.  This cycle would occur every 10 to 15 minutes apart.  I replaced the batteries and the problem continued.  I shed all loads except for my single stand alone computer and it's external back-up hard drive yet the problem persists.

[BillP]

Hi John,

Are you experiencing/have you recently experienced power problems in your area?  Have you confirmed steady input voltage to the unit?  Are there any other indicators lit on the unit to mention? Obviously these units switch to battery when they sense an input power issue if working properly.  

To further troubleshoot this issue (if you have already confirmed steady input power), I would turn the unit off, unplug the load on this unit, unplug the unit from utility power, remove the battery, and hold the off button for roughly 20 seconds to completely de-energize the unit.  I would then reverse all the steps and observe any changes to the unit.

[Anonymous user]

To my knowledge, I have not experienced any power problems in my area recently.  I have not confirmed a steady input voltage to the unit; however, I have another UPS on the same circuit and it has not exhibited any on-line/on-battery switching.  I suppose that I still ought to buy the tools necessary to check this.  The only lights on the unit that turn on and off are the on-line green light and the on-battery orange light.

I carried out the your suggested procedure to de-energize the unit.  After 10-15 minutes of on-line operation, the unit resumed its periodic switching to on-battery for a couple of seconds and then back to 10-15 minutes of on-line. 

[BillP]

If you are able to connect PowerChute Business Edition Agent to the UPS via USB or serial on your computer, it may prove helpful in understanding what the UPS is seeing as the problem. It would also allow you to change the UPS sensitivity setting to see if it changes anybehavior.

If the other UPS is a different type/model, it could have a different sensitivity threshold and not necessarily mean there is a "problem." If it is the same model of SC1000, it could also have a different setting potentially.

[Anonymous user · Accepted solution]

I downloaded PowerChute Business Edition Agent from APC and when istalling it, my antivirus software, STOPvilla, stated that it had detected a malicious or potentially harmful program, TrojanDropper.Win32,Plhar.  I used STOPzilla to isolate the file and repeated the process only to get the same warning.  I abandoned the process.

Oh, my second older UPS is an APC BF500 through which my periferals get power.