To my understanding, most solar controllers use some form of PWM to output a desired current/voltage combination. These seem to often do some sort of DC-DC conversion.

This seems to be wasteful and inefficient however. During the off period of the PWM cycle, the sunlight hitting the PV panel is not used or stored for future use. So a controller using PWM at an 80% duty cycle can only be 80% efficient.

  1. Is my understanding of the situation correct or am I missing something?

  2. During the off period, could the PV power be diverted to charging another LC circuit so it isn't wasted?

  • 4
    \$\begingroup\$ The DC-DC convertor will have an input capacitor, which stores the charge from the solar cell when PWM is off, and releases it when PWM on. Very little is wasted. \$\endgroup\$ – user_1818839 May 21 at 14:03
  • \$\begingroup\$ Thank you. That makes sense. \$\endgroup\$ – cbake May 21 at 14:22
  • \$\begingroup\$ Solar controllers are designed to extract as much energy as possible from the input source. Most are achieving efficiency well above 90% these days. \$\endgroup\$ – jwh20 May 21 at 15:38
  • \$\begingroup\$ they use 'some form of PWM'. An efficient form, for converting power, not an inefficient form, for crude dimming of LEDs. \$\endgroup\$ – Neil_UK May 21 at 16:25

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