UPS batteries will eventually need replacing, as their charging capacity will slowly reduce after years or even just a few months of usage. Usually, you’ll know your batteries have gone bad when they start to have a bumpy exterior. In some cases, they may even start bulging right out from their outlets or sockets. This commonly happens when the battery’s circuit is charged too high, in which case it will experience extensive power fluctuations. When this happens, the batteries may end up ‘fried’ and deemed necessary for a replacement.  UPS Batteries