Self-Test Depletes Battery Capacity Considerably on Smart-UPS RT 10000 XL

[BillP]

We have two Smart-UPS RT 10000s, neither has any external battery packs installed:

UPS "A" Smart-UPS RT 10000 XL only has a 15% load and had two new RBC44/140s installed last October. A runtime calibration of this UPS was passed in March this year and resulted in 1 Hour 6 Minutes runtime. It was manufactured 23/6/05. But when a Self-Test is run on this UPS, it depletes the battery capacity to 61%.

UPS "B" Smart-UPS RT 10000 XL also had two new RBCs installed last September and has a greater load of 30%. Its runtime calibration was recently passed resulting in 30 minutes runtime. It was manufactured 20/6/08. Yet its Self-Test only depletes battery capacity to 90%, which is also consistent with the Self-Test results of the other 80 or so APC UPSs of various models that we operate.

So what would account for the huge drop in battery capacity when running the Self-Test on UPS "A"?

[BillP]

Hi Roly - 

I would run another calibration on UPS "A", but I would first make sure that there is more than 30% load attached. I think the issue is likely related to calibration rather than a faulty battery issue. 

[BillP]

Hi Liam

Thanks for your reply. That's an interesting point, but I was under the impression from APC documentation that a UPS would refuse a calibration if there was not enough load present. In this case the calibration was allowed, so I assumed that the load was sufficient and hence that the resulting calibration was valid. Certainly it would be interesting to see what effect doubling its load would have.

However, the UPS is at a remote site some 50km away and given that its a 10kVA unit, doubling its load would present some practical problems.

I found a FAQ that suggests running a "Manual Runtime Calibration" in order to reset the microprocessor. http://www.apc.com/us/en/faqs/FA156538/ Option 3. But this would require downtime of the attached network equipment, so I'd rather not do that unless absolutely necessary.

I'm now also in discussion with APC Support about this issue so I will post back here when I have heard back from them.

[BillP · Accepted solution]

Hi Liam

Just to let you know that during the process of resetting the calibration counter and then running a self-test, a faulty battery was identified. Replacing the batteries seems to have fixed the problem