Enter the characters you see below Sorry, we just need to make capacitor ripple current specification you’re not a robot. I have two of these units with the same fault and I have also read about this problem on usenet.
The problem is that the Back-UPS RS 500 stop charging the battery. For me it was easy and not expensive to repair them. If you have some experience with soldering it should be easy for you too to do the repair work. Before you start, remove mains power and the battery. This unit is generating high voltage from a 12 volts battery and a battery like this contain a lot of energy. Please take notice of any safety precautions.