PWM (Pulse width controller) charge Controller
This type of charge controller charges the batteries by sending out short pulses of current to the batteries, hence the name.
It monitors the battery state and varies the nature of the pulse it sends accordingly, during the bulk stage when the battery is low, it sends long and continuous pulses and it sends it out rapidly. It monitors the battery and as the battery starts getting fully charged, the frequency of the pulse decreases, It doesn’t send it as rapidly as before anymore and the pulses become shorter and shorter, this is done so that the battery is not overcharged.
PLEASE NOTE. For a PV module to charge your batteries, the voltage of the PV module must be higher than that of the batteries,
PWM charge controller is cheaper than the MPPT charge controller, it is easily affordable. It can be used for small scale solar projects.
It is not as efficient as the MPPT charge controller.
.2) Small scale projects
It can’t be used for large scale projects 60amps and above.
.3) Voltage conversion
It can’t convert the excess voltage to current.
MPPT (Maximum Power Point tracking) charge controller
This is actually a much more recent type of charge controller. The MPPT charges the battery by sending out the maximum power possible to the battery hence the name. It monitors your PV module and your battery and determines the most appropriate power to send.
One of its most distinguishing features is its ability to convert excess voltage from the panel to current for your systems.
It has a higher efficiency compared to the PWM.
.2) Voltage conversion
It converts excess voltage to current for the system.
.3) Large scale projects
It can be used for large scale projects
It has a higher cost compared to PWM.