This is a protection board for packs of lithium ion cells, you choose 3S (12.6V) or 4S (16.8V)
I have “BMS” in the title because that’s what people search for but please note this type of protection board is NOT a charging board, you still need to use an appropriate CC (or CC+CV) charger to charge packs, this handles protection (over DISCHARGE current, over voltage, under voltage, and short circuit).
This board does not do balancing. Balancing really doesn’t help you much when each cell is protected, provided your cells are all charged to the same voltage when you build your pack and are in good health, then just protection only will do, few commercial packs bother with balancing.
In theory the working current (that is, constant in free air) is 40A for this module, and the over-current is about 80A (that is, you're going to trip it out at that).
See the images for more specifications, and in fact there is even a datasheet of sorts (this is the “enhanced” version). It notes that if powering a brushed motor “try to connect a non-polar capacitor, 10-100uF scross the motor to protect against reverse spike voltages”.
If you are buying this, you already know what you are doing, or you shouldn't be playing with fire, Lithium Ion battery cells can be dangerous.
Never rely on just one thing to protect you, others, or your things, always have a backup plan - in other words, if your quad plummets to earth in a spectacular flaming ball because a cheap Chinese protection board blew a mosfet, I'd be happy to replace the board, the quad, not so much. Like any component from China, you assume some risk. Sorry I have to say that, but it's the world we live in :-/
All of our products are shipped from Christchurch, New Zealand using CourierPost for NZ, and Airmail for international.
