One of the things people forget is that there is a limited life to the sealed batteries in UPS battery back-ups, alarm systems, emergency lights and exit signs, and various other products. If it has been over 3 years you may want to consider replacing these batteries before there is a problem. At the very least overcharged batteries will fail when they are needed most. The batteries can also bulge and distort so they are very difficult to remove. Contact us to see how inexpensive it is to replace these batteries before there is a problem.