Incorrect reported runtime after calibration

[rajil.s_apc]

Sorry i had posted in the wrong forum, so reproducing here.


Hi,

I bought a new APC SUA1000UXI UPS about a month ago. The UPS is running over two 12V Exide 7AH batteries. Over the past one month the reported runtime (using apcupsd/suse linux) decreased from about 120 minutes to about 7 minutes. I reported to APC customer care and an engineer was sent out to have a look. It seemed there was a calibration problem and the service centre guy corrected the battery constant to '7F'. Now the UPS is again reporting a run time of 112 minutes at 11 percent load.

To verify that the runtime was accurate i switched off the main and let the UPS run until it drained itself. The batteries died in about 11 minutes. I have specified a minimum remaining time of 2 minutes and minimum battery charge of 5%. So the actual backup time could be about 10 minutes. Is there a problem with the UPS? The batteries are new. If somebody is tracking the APC support emails, the incident number for this is Incident: 110530-000011.

The battery characteristics recorded just before and after i killed the mains are below. The UPS was showing remaining time of 91 minutes before i killed the power at 21:02. The next recording at 21:10 showed a remaining time of 20 minutes and the UPS shut itself off at 21:12. After the UPS charged the batteries to 100% capacity, the reported backup time has again risen to 118 minutes.

Date Time Remain Batt % Remain Battery Voltage Temp Line Frequency Line Voltage Load %
5/30/2011 20:55 91 100.0 27.40 33 50 218.80 13.60
5/30/2011 21:00 91 100.0 27.40 33 50 216.02 13.60
5/30/2011 21:05 47 52.3 24.22 32 50 1.44 13.60
5/30/2011 21:10 20 23.1 22.90 32 50 0.00 14.30
5/30/2011 21:30 62 65.0 27.30 34 50 252.00 13.60
5/30/2011 21:35 68 68.0 27.30 34 50 254.78 12.31
5/30/2011 21:40 71 71.0 27.40 33 50 253.41 12.30
5/30/2011 21:45 71 75.0 27.40 33 50 249.11 13.00
5/30/2011 21:50 74 78.0 27.40 33 50 250.49 12.31
5/30/2011 21:55 82 82.0 27.40 33 50 249.11 13.00
5/30/2011 22:00 86 86.0 27.40 33 50 253.37 12.30
5/30/2011 22:05 89 89.0 27.40 33 50 250.53 12.30
5/30/2011 22:10 92 92.0 27.30 33 50 249.11 13.00
5/30/2011 22:15 96 96.0 27.40 33 50 247.61 12.30
5/30/2011 22:20 100 100.0 27.40 33 50 250.48 12.30
5/30/2011 22:25 100 100.0 27.40 33 50 249.11 12.30
5/30/2011 22:30 100 100.0 27.40 33 50 244.83 13.00
5/30/2011 22:35 95 100.0 27.40 33 50 246.19 12.30
5/30/2011 22:40 100 100.0 27.40 33 50 241.91 12.30
5/30/2011 22:45 118 100.0 27.40 33 50 236.14 9.12
5/30/2011 22:50 118 100.0 27.40 33 50 240.37 9.10

Thanks
Rajil

Message was edited by: rajil.s