Comidox 3S 12V 10A 18650 Lithium Battery Protection Board BMS Li-ion Charger Protection Module Anti-Overcharge/Over-Discharge/Over-Current/Short Circuit 3Pcs

No issues at all. Made 3 battery packs using 3, 18650 cells. These prevent overcharging, and shut down when voltage is low. Exactly what I needed. +++++

Worked wonders! Converted our nursing facilities feeding tube machines that works on 12v 2amp lead acid batteries to 18650 lithium batteries..bench tested for a week draining the diy battery pack and charging it back multiple times in the our baxter infusystem feeding tube machines before sending it back to the floor for patient use..5 done, 10 more units to go.. just do remember they need to be charged 1st before its going to work.. its for safety reason they did this for it to work the very first time..there will be no voltage outputted if you don’t charge this on your first use so be aware..

Works well but has no output until a voltage is applied to the input/output terminals. Charge current is pulsed so if you use this on a solar setup, you'll need a hefty bulk capacitor to store the charge current energy or it won't charge the Li-Ion cells correctly. Works great as a BMS if applied correctly.

They are doing that, what i have paid for.

I used this to build a battery it work right away one thing though it doesn't say this in the instructions it comes in a safety mode so you can connect the battery cells you MUST appy a charger to the finished battery to take it out of safety mode even just for a second you wont get an output until you do i see a bunch of people say it didnt work but you HAVE to charge it first

They are good, work well and keep the pack hovering around 12.6. Must charge through circuit in order to activate.

they are bad, all 3 out of the box are bad, charged with 12 volt in like its specified, and all 3 boards went up in smoke. literally. they look okay for quality, but they do not work.

I had a similar experience to another reviewer: the first board I connected charged all the batteries up to ~4.2v but afterward would not output anything. I connected the other two boards and they seemed to do nothing. They wouldn't output any power, and they wouldn't draw anything to trip the protection circuit. I thought perhaps they were tripping the overcharge protection but the batteries are each below the threshold shown in the listing and still no joy. I will continue to drain them separately and see if I can find a point where the circuit will start to charge them back up, but unless there is something I am missing, I am not holding out much hope for these.