AS Series Inrush Current Limiters Ametherm AS Series Inrush Current Limiters provide thermistor protection for precharge circuits on lithium-ion batteries. With a lower current density, faster reset time, and uniform temperature gradient throughout the disc, there are no hot spots from fatigue. The series provides inrush current protection for 250 to 1000 joules of input energy and allows between 10W to 18W in the 10A to 50A SSI range and up to 900 joules of energy. Ametherm Inrush Current Limiters are designed to protect components from damaging levels of inrush current at startup.