I have a CN3791 module, the 6v and 12v versions:
How can I tweak it to run on 4v to 10v input range?
That's not how these MPPT modules work. You buy them for a certain solar panel voltage, which is 6, 9, or 12volt. They try to keep input voltage at a constant 6,9,12volt, to extract max power from the panel. MPP voltage is set with two resistors. Seems like R1,R2 on that board.
Energy harvest is likely a lot less if you use the wrong panel voltage.
Leo..
@shamooooot
This module that you posted the image of uses CI CN3791.
This IC's datasheet states that the IC's lowest input voltage is 4.5 V,
CN3791 Features:
Wide Input Voltage: 4.5V to 28V.
Therefore, for you to use 4.0V you will need to find another module to buy.
CN3791 Datasheet:
CN3791.pdf (205.8 KB)
The module uses a buck converter to charge a 4.2volt battery.
That's probably the main reason for the minimum of 4.5volt.
Leo..
Thanks for the rplies.
It's fine 4.5 is very good, but can I make it work on cell voltage between 4.5v to 10v?.
No, The chip is designed to charge a single LiPo cell, and that can't be changed.
The only thing that can be changed is solar panel voltage input.
Leo..
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