Battery protection system provides over-discharge, temperature and current protection for enhanced performance, battery cycle life and overall battery life (when used with STAR marked tool. Offers more cycles over the life of the battery vs Ni-Cad and Ni-MH batteries. Optimum charging system utilizes 3 active controls (current, voltage and temperature) to maximize battery life. Built-in memory chip communicates with charger CPU to optimize the charging process based on the unique conditions of each battery.