Charge controller is DC IN-DC OUT device. We can use charge controller to run DC appliance directly i.e Solar street lights, or we can store current as backup in batteries. In Usual routine we use charge controller to charge batteries from Solar Panels. Charge controllers can manage up to 150 Volts from solar panels and are capable of to convert into 12, 24, 36, 48, 60 or 96 volts and charges the battery. A charge controller should prevents batteries to be over charged and cutoff charging when battery is fully charged in order to expect longer service life of battery. 

There two general types of charge controllers available in market.

i.   PWM (Pulse Width Modulation)

Effective to achieve constant voltage battery charging by switching the solar system controller’s power devices. PWM charger regulates the current from the solar array tapers according to the  the battery’s condition and recharging needs.

PWM charging technology is effective for small level or domestic use.

ii   MPPT (Maximum Power Point Tracking)

is algorithm that included in charge controllers used for extracting maximum available power from PV module under certain conditions. The voltage at which PV module can produce maximum power is called ‘maximum power point’ (or peak power voltage). MPPT charge controllers are used at commercial level, water pumping system or to obtain  high voltages. The Power point tracker is a high frequency DC to DC converter. They take the DC input from the solar panels, change it to high frequency AC, and convert it back down to a different DC voltage and current to exactly match the panels to the batteries. MPPT controllers will get the most out of your PV array, and actually are more beneficial in off-grid applications because they produce the most benefit in the cold winter months when the batteries tend to be at a lower state-of-charge—right when you need the energy the most!