BACK-UPS XS 900 wont charge fully

[Anonymous user]

I recently replaced the batteries in my BACK-UPS XS 900 and it wont charge them beyond 91%. I've tried two different sets of batteries and it has once or twice gone over 91% but it always seems to settle back down to displaying that level of charge in PowerChute.

Powerchute shows "Remainging battery charge: 91%" and shows "Battery is currently: Charging"

Any idea how I can recalibrate the charge level. I tried running down the UPS on battery to around 7% and then recharging.

Windws 7 Professional
Powerchute 3.0.0.1

Thanks, Tom

[BillP · Accepted solution]

Hi Tom,

In performing manual runtime calibration, please follow these steps:

1. The UPS must have at least a 30% load on it during the calibration.
2. The load cannot fluctuate more than +/- 5% during the calibration.
3. Unplug the UPS from the input source and let it run on battery until it gets discharged.
4. Charge up the UPS/battery back to 100%

In addition to the abovce conditions, any UPS monitoring/shutdown software should be stopped from running in the background, and the serial cable should be detached from the UPS. This is necessary in order to prevent the software from shutting down the server/UPS due to an on-battery or low-battery condition