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mini FPVR solar lipo charger board (CN3791):




These little boards use a mini solar controller with buck regulation on the solar panel. They're configured
to charge single (3.7v) lithium batteries such as 18650, or small single cell lipo pouch batteries. It's
got good battery maintenance, including slow initial charge, bulk charge, and float charge modes.

Beware, this isn't MPPT, it's FPVR. (Fixed Panel Voltage Regulator) You will need to make sure the panel's
Vmpp matches the fixed voltage of the board you select. (I've seen 5, 6, 9, and 12v configurations) If your
panel has some other Vmpp, you'll need to adjust R3 and R4 to produce 1.205v for the chip to "track". They're
small, good luck!


2025.11.28 panel and lipo charge board testing (in test sessions)

CN3791 FPVR 1-cell controller.pdf (in solar controller ICs)


mini solar lipo charger board ($5 at Ali Express)

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last updated 12/13/2025 at 20:45:15 by make_www_index.command version 2025.11.05.A