We have a vista-15 security system. It should run on the electrical system with a battery backup. At present, it works perfectly fine on the AC alone. When I connect a correct and tested battery, the system runs ok for an hour or two, and then the electrical connection stops working and the system is running on battery only. When I now disconnect the battery, it takes about
3-4 days to restore the system to start working again on AC. Any comments would be greatly appreciated.