Morningstar ProStar's technology provides exceptional reliability, PWM battery charging, consistent high quality and low cost. All ProStar solar controllers use Pulse Width Modulation (PWM) technology to maximize charging efficiency. PWM is the most effective means to achieve constant voltage battery charging by switching the solar system controller's power devices. When in PWM regulation, the current from the solar array tapers according to the battery's condition and recharging needs. After battery is fully recharged, Morningstar ProStar solar controllers reduce to a float or trickle charge. The transition depends on battery history. A load that exceeds available solar output will return ProStar to the PWM mode. Flooded cells receive a vigorous equalization, sealed batteries a smaller boost to bring uneven cells into balance and extend the battery life. Gel cells are not equalized. An automatic load disconnect protects the battery from deep discharge. The load automatically reconnects when the battery recovers. A 4-minute delay prevents false LVD disconnects.