Pulse Width Modulation (PWM) is 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.

When a battery voltage reaches the regulation point, the PWM solar charger slowly reduces the
charging current to avoid heating and gassing of the battery, yet the charging continues to return
the maximum amount of energy to the battery in the shortest time. The result is a higher
charging efficiency, rapid recharging, and a healthy battery at full capacity.

PWM solar charger will benefit you receive more solar energy acceptance and keep your battery longer life span.