Types of Solar Charge Controllers
The two types of charge controllers most commonly used in today’s solar power systems are pulse width modulation (PWM) and maximum power point tracking (MPPT).
Size of the System
Low power systems are better suited to a PWM controller because:
PWM controller operates at a relatively constant harvesting efficiency regardless of the size of the array
PWM controller is less expensive that a MPPT, so is a more economical choice for a small system
MPPT controller is much less efficient in low power applications. Systems 170W or higher tickle the MPPT’s sweet spot
MPPT controller is quite expensive but give maximum power to batteries from panel and has less cable loss