How to choose PWM or MPPT controller for my solar DC power system?

27/05/2020

Many solar power system users may have headache about how to choose a controller for their solar power systems, PWM or MPPT? Commonly, we have a few guidelines for this:

   1) If your system is very small, like PV lower than 100W, PWM may be better. However, if you system has a high demand on charge amount, you also can choose MPPT, like some solar light with high LED power.

   2) If your PV array’s voltage is much higher than the battery bank, like 12V battery, but 30V PV system, then no doubt you need to use MPPT. Almost all thin film PV arrays (very high voltage) have to use MPPT.

   3) If you use Sun Power cells assembled modules, then it’s better to use MPPT.

   4) If your PV module voltage is very close to the battery voltage, like 30V module to a 24V battery bank, or 18V module to a 14.8V lithium battery, PWM charge may have an improved charge efficiency, sometime could be up to 90%. * please notice that the PV voltage shouldn’t be lower than the battery charge voltage all the time while it’s working.

   5) If the PV voltage is very close to the battery bank voltage, then MPPT may not work very well, and in some cases like that, MPPT charge may never begin in the whole charge time.

   6) If you still have no idea about how to choose, then please contact us.