Pulse Width Modulation Regulators - Two Stage ChargingSimple PWM Budget PWM Premium MPPT
Pulse width modulation (PWM) regulators are more sophisticated than the simple regulators. In float mode (after the initial charge), PWM controllers regulate the voltage (and current) by turning the switch between supply and battery on and off at a very fast pace. The longer the switch is on compared to the off periods, the higher the power supplied to the battery is.
The Morningstar regulators also consider ambient temperature to calculate the optimum charging rate. It is therefore recommended to have the those close to the batteries (but not too close!).
The Morningstar Lighting Controller also has a timer to switch loads (e.g. security lights) on and off at night time. It uses the PV array as a light sensor to determine on/off times.