This is a 3 stage automatic smart wheelchair battery charger. It will not damage your batteries if left connected. Used with the following wheelchairs: Invacare Pride Mobility Hoveround Freedom DDC Shoprider E-Scooter Electra Frank Mobility Merits Health Products Theradyne ...and others with batteries less than 25 amps! Replaces the 24BC3000T-1 charger.