The 3 Series 40A 18650 Lithium Battery Protection Board (11.1V–12.6V) with balance function is designed for high-drain applications like drill motors, e-bikes, and LiPo cell modules. It ensures safe battery operation with overcharge, over-discharge, overcurrent, and short-circuit protection. The built-in balance feature maintains equal voltage across cells for longer battery life and stable performance. Suitable for 3S battery packs requiring up to 40A continuous current.