4 Pack 3S 40A Battery Management System for 18650 Li Ion Batteries, 12V to 12.6V Safe Charge and Balancer Board, High Current Protection for Drill Motors, LiPo Li Ion Charger PCB and Battery Protection Module

Top Shelf 3S 40A Li Ion Power Balancer Circuit
✔️ 3S 40A 12.6V lithium BMS prevents overload and matches cell voltage automatically

This 4 pack of 3S 40A lithium battery management boards handles safe charging and balancing for 18650 or polymer cells. You typically mount these protection circuits inside cordless power tools, agricultural sprayers, and low wattage LED lighting rigs.

✅ Nominal 3.7V per cell with 4.2V full charge rating
✅ Continuous discharge peaks at 40A and charging caps at 20A
✅ Built safeguarding covers overcharge overdischarge overcurrent and short circuit events
✅ Compact footprint measures 41 by 61 by 4 millimeters

💡 What keeps a multi cell lithium pack handy when you run a hot drill under heavy load? - Cell tracking balances the chemistry straight through the swap cycle so nothing blows heat - Fast trip circuits kill power quick enough to spare your cables and motor pins from frying - Bleed resistors handle stray voltage spikes on the fly before they mess up the entire array