Fault (1/1) battery not connected

[jcclaros777]

I have an APC 20KV UPS model G3HT20KHB2. In the panel it shows me the error: "fault (1/1) battery not connected". I have checked the batteries one by one and they are all connected. What I did find is that a couple of batteries were sulfated and with very low charge. The equipment was out of service for almost 3 years.

[dpierce4776]

Parson me if I am not understanding your question but it appears that you are asking why you are getting a battery disconnected alert even though all batteries are connected. 

If that is the case this is one of those things that APC does not alert on well. More that likely you have one or more batteries that have failed open. Meaning that while they are connected they are not supplying any voltage to the system so it does not see enough voltage coming from the batteries and thinks the batteries are not connected. Replace all the batteries as one or more bad ones can drag them all down and damage all the batteries. And the alert should clear.