The following article applies to the following models:
UPS Interactive: SL-501,SL-701, SL-502 ,SL-702, SL-1001, SL-1002.
This video will help you to open and replace your current battery for new working battery.
The model used on the video is a SL-750, minor details may vary on the removal and installation of your battery, the video is just to guide you through the process.