5S 18V 21V 20A Lithium Battery Charging Protection Board

5S 18V/21V 20A Lithium Battery Charging Protection Board – BMS for 5 Series Li-ion Packs

Protect and optimize your 5-cell (5S) lithium-ion battery packs with this 5S 18V/21V 20A Charging Protection Board, a feature-packed Battery Management System (BMS) essential for DIY battery building and power tool applications. This smart module manages charging, discharging, and cell balancing for 18V/21V pack builds—preventing overcharge, over-discharge, overcurrent, and short-circuit events. Its onboard MOSFETs, ICs, and heavy-gauge wiring ensure up to 20A continuous current, making it ideal for e-bike, drone, robotics, or backup power bank stacks.

Clearly labeled solder pads and included pre-wired harness ensure straightforward wiring and installation. Designed for all common 18650/21700/26650/Power tool battery projects.

---

Key Features

• Suits 5S lithium-ion (18V/21V nominal) battery packs

• Maximum continuous discharge current: 20A

• Cell balancing and equalization circuit for longer pack life

• Advanced IC management for overcharge, over-discharge, and overcurrent protection

• Built-in short-circuit and temperature protection

• Input: 21V DC max charging voltage

• Output: Up to 20A continuous, suitable for power tools, e-bikes, inverter packs

• Pre-wired heavy-duty leads (red, black, yellow, blue)

• Compatible with all standard cylindrical Li-ion cells

• Compact PCB: ~55 x 45 mm (references may vary)

• Easy to integrate for new packs or pack repair

---

Applications

• Custom lithium battery packs (power tools, e-bikes, solar banks)

• Robotics and RC builds

• DIY energy storage and inverter systems

• Power tool battery pack repair/upgrades