declining battery charge

[Anonymous user]

Back-up ES 750. A few months ago I noticed that my battery charge percentage was slowly but steadily declining after it had been at 100% since I started using the backup a couple years ago. So I thought it was just a bad battery and put a new one in. It went to 100% shortly afterwards and I thought everything was good. But then after a couple weeks it too started to slowly decline and it is now at 21% after about three weeks. It's hard to believe that it's the battery at fault. What could possibly causing this? (Using a Mac Pro, OS 10.11.6)

[Anonymous user]

I posted this over two weeks ago and 66 people have looked at it, but NO ONE has bothered to respond. My charge percentage is now zero. Is it possible that my ES 750 is for some reason just not charging the battery? Could it be a software glitch?

[BillP]

Hi David,

Sorry for the delay. It may be a battery charger issue. I would try manual runtime calibration test to calibrate the battery and this will prove whether it's a software glitch or unit issue. Here is the procedure.

1. Please connect at least 30% load attached to the UPS during this procedure. This process will cause the UPS to shut off and cut power to its outlets, therefore, attach a non-critical load like a bulb to the UPS and then force the UPS to the on-battery mode by disconnecting it from utility power. Allow the unit to run on battery mode until it turns off completely. Make sure at least 30% load is present!

2. Plug the UPS back into the wall outlet and allow it to recharge (it will recharge more quickly when turned off and with no load present).

Check if the UPS battery provides back up power or it turns off as soon as it is disconnected from wall outlet?

Regards,

Vinay

[Anonymous user · Accepted solution]

For the record, the problem was simply a defective back-up unit. I bought a replacement on ebay without a battery, put my new battery in, and it's now charging normally.

Very odd that no one on this forum would have suggested that this could have been the problem . . .