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Member #16204

Member Since: March 6, 2007

Country: United States

  • Hi Sparkfun,

    I think you may have an issue with your circuit - This IC isn’t really a true MPPT IC, it just “guesses” the MPP based on an assumed maximum power point voltage. You have to put a voltage divider on the VIN_REG pin such that the converter regulates the input voltage to the known maximum power voltage of the panel. This voltage actually does vary, but it does so with temperature, not sunlight. so based on your current schematic, with the Vin_Reg pin tied directly to the vin node, you will only be optimized for panels with a lower voltage (looks like around 4V based on your graph). You really need to have a potentiometer on this node, which users would adjust to find the MPPT with a new panel. I hope this helps, and do not mean to come across as critical.

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