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Your cart is empty.When the current output capacity of the input power supply is reduced, the CN3791 internal circuit can automatically track the high power point of the solar panel, and the user does not need to consider the bad situation, which can maximize the use of the output power of the solar panel, which is very suitable for the application of solar panel power supply. Package included: 2pcs CN3791 MPPT Solar Panel Solar Charger 3.7V 4.2V Lithium Battery Charging Panel Module, 12V Solar Panel Charger Regulator Control Module, JST PH2.0 Auto Recharge for Battery.
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Reviewed in the United States on April 13, 2025
I bought the CN3791 MPPT solar charger thinking it would help maintain and charge my 3.7V lithium batteries from a 12V solar panel setup. On paper, it looked promising with MPPT and auto-recharge features, but in actual use, this thing is a nightmare.Not only does it fail to charge efficiently, but I found that it actually pulls power away from the batteries or the devices they’re powering. When my connected device is running (even at low draw), this charger drains the battery instead of supporting it with solar input. It feels like it fights the load instead of helping it. I ran tests over multiple days with different panels and setups to confirm this behavior — same results every time.The worst part? When there's insufficient sunlight, instead of cutting off like a proper regulator should, it allows weird voltage behavior that ends up damaging or at least severely draining the batteries. I've had a couple of otherwise healthy cells go weak after running through this thing.Bottom line: this module is more harmful than helpful. If you're trying to keep something powered reliably via solar, avoid this product at all costs. Spend a few more bucks and get a real MPPT charger from a trusted brand. This one's a battery killer, not a charger.
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