5Pcs 2A USB 18650 Lithium Li-ion Battery Charger Module Boost 3.7V to 5V 9V 12V

I used this board to add batteries to a MIDI controller, and it works quite well. My multimeter shows that the output can be adjusted from 3.7v to 27v, although I've only used it to provide 5v power. The board is quite small, and can manage multiple cells in parallel (make sure they're all at the same voltage before you do so though).if I ever need more 3.7v battery management boards, I will be buying these again.

The usb jacks on all but one of them just fell off in my hand. None would work under load. I could adjust the voltage to the correct value but as soon as I put any sort of load on them they would just shut off.Very disappointing given how expensive they were. They're going in the trash.

I charged 12 18650 Lithium Li-ion Batteries one after the other and they came up perfectly and stopped when the batteries full.

These can't really be used in dual mode where you power the device and charge the battery at the same time. The charge cycle never completes because the load confuses the controller. (This can over charge the battery as well) They can however be modified with a cut and two Schotky diodes and they work like a champ. It would also be nice if the Charge and Done pins were made available so they could be monitored by an external device.

I bought these a while back and just started using them. For my application I needed to have these modules to take a 9Vdc input and output 14V to a amplifier circuit which presented a very light load of ~8mA. Although once adjusted for the required voltage output they worked for a short time and then upon power up the went int a short circuit mode. This appears to happen randomly but 3 out of five modules failed in the same way. It appears that these things have some nasty flaws...so far I think this is pure junk.

Me parecio buen producto y tamaño adecuado para mis proyectos

Completely fell apart one that didn’t fall apart would not recognize the USB not worth the money very disappointing in the products what a shame

My device kept restarting and after measuring the current I noticed this module resets at about 595mA at 5v. Much lower than the 2000mA advertised.