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Please make sure that you have charged the batteries for 24 hours before doing this.

Runtime Calibration:
- Stop the APC software running on your computer and disconnect the USB cable.
- Remove all critical loads on your UPS and make sure that you have at least 30% load on it.
- Unplug the UPS from the power source and let it run On Battery until it discharges completely.
- Once the UPS is completely discharged, reconnect it back to the power source to recharge.
- Reconnect the load and cables back to the UPS and check the APC software for the runtime.

I just got my problem solved and very excited. Here are the steps i have taken:

1. Uninstalled APC PowerChute Personal Edition Version 2.2 downloaded from the site.
2. Managed to get hold of my previous APC PowerChute Personal Edition Version 1.3.1 for Windows 98/Me/2000/2003/XP that shipped with the UPS.
3. After the installation, I found the following option under Monitor System>Run Self Test:
To Help PowerChute to keep track of battery life, please click HERE when you replace battery on clicking it the following popup appeared Are you sure that you want to update your battery's replacement date now. On clicking, it instantly reported the estimated battery time as 45 Min!!!!.

Reseting 

To do this, power down all equipment attached to the battery outlets.

Then reboot the Back-UPS ES by turning it off then count to 5 and power it back on.

If the constant tone clears, then it was a false onbattery condition and the unit has been reset. It now is ready to be used again. 

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