HiLetgo CN3791 Solar Charge Controller Board MPPT 1 Cell LiPo Battery Charge 12V Solar Panel Charger Regulator Control Module JST PH2.0 Auto Recharge for Battery withCables

These devices are 12v only despite the directions suggesting they make 6v versions. I emailed manufacturer and they they only make 12v. They work as stated and it performs well.

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.

Easy in and out with JST connectors. Everything is well labeled and it seems to work just fine. Noticed today there is an LED that lights up when things are working OK. I have no idea how long these might last, but they are very inexpensive. I use it to control the panels charging a 3.7 volt LiPo battery powering an Arduino at a remote location.

Part failed on first test.Set a CV/CC PSU to 12V/600mA to simulate my 10W solar panel in less than full sun (since this should be around 7.2W).When connected the charge controller with a battery already connected, the voltage fell to 11.5 and the full 600mA was pulled. The battery being charged was simulated to have "died" from the lack of sun, so when the charging started, the cell voltage was around 2.5V (the cells used are rated to be drained down to this voltage).Assuming ~85% efficiency of the controller, the power pulled in should result in the charge current of 2.18A, which is higher than the max 2A current.For the first 30 minutes the controller heated up to ~60 degrees where the inductor is, after another 30 minutes I observed smoke from that spot and the inductor unsoldered from its own heat and fell off the board.My understanding from the description is that the controller will limit the charging current to 2A and giving a bigger solar panel will allow it to collect more power when not in full sun exposure and when in full sun, the controller would not utilize 100% of the solar panel.In reality, looks like the device will use all that it gets and there is no over-current or over-temperature protection on this module and if you give it enough time under too much power, it will melt.The controller NEEDS to be paired the smaller panels (guessing that the 3W would not cause the failure).If this was clear from the description, I would not complain but there was nothing suggesting that I need to limit the input current in my circuit design so that the result charging current would not pass 2A.

bought this to charge a LiPo 10000mAh battery and power a RAk wireless wisblock node, but over the course of a week, the battery level declined until the wisblock shutdown. Ended up removing this and connecting directly.

good product