Replace Battery Signal Too Soon?

[Anonymous user]

Previous APC models I have used at work that have tandem batteries, such as the the Back-UPS Pro 1000, would almost always die because one of the two batteries developed a short. Over the last weekend I had three Back-UPS RS 1200 models turn on the Replace Battery light, and in these instances both batteries test good, although obviously not as strong as when they were new. Is it just me or is the RS 1200 being more conservative in deciding when it needs new batteries? The net result will be buying more batteries ...

[BillP]

all of the UPSs compare the voltage drop while on battery to a chart that it has within its firmware. if it is out of that range, then a replace battery indicator is signaled.

how old are these UPSs and batteries? where are they located? keep in mind environmental factors can affect battery lifetime. also, if the unit was bought after sitting for a year or so at a retailer, it can appear they are brand new but the batteries were sitting in storage.

[BillP · Accepted solution]

The batteries don't necessarily have to be completely dead/damaged etc to fail a self test(which causes the replace battery led). The UPS does a self test every 2 weeks by default which checks multiple things such as discharge rate.. If the self test fails due to this or similar, you will not necessarily see that when testing the voltage, fuses, short etc. If you think the battery should be OK(due to age etc), you can initiate another self test to see if is passes.