BMS Protection PCB for Black & Decker 20V 21700 Li-Ion Battery

Li-Ion Battery Protection Circuit Board for Black & Decker 20V 21700 Power Tool Batteries

Keep your power tools running safely with this replacement Battery Management System (BMS) Protection Circuit Board (PCB), designed specifically for Black & Decker 20V lithium battery packs using 21700 battery cells (5-cell or 10-cell configurations). Whether you're a DIY battery rebuilder or an experienced electronics technician, this board gives you the protection circuitry you need to safely assemble or repair your own 20V battery packs.

⚠️ Important Notice: This listing is for the PCB protection board only. No battery cells, battery box, or charger are included. This product is intended for individuals with hands-on experience in battery assembly and electronics repair. If you are unfamiliar with lithium battery assembly, do not purchase this item.

Made in Mainland China.

Key Features

• ✅ Compatible with 21700 Li-Ion cells only — NOT compatible with 18650 cells
• ✅ Supports 5-cell (5S) or 10-cell (10S) battery pack configurations
• ✅ Designed for Black & Decker 20V power tool battery packs
• ✅ Provides overcharge, over-discharge, and short-circuit protection
• ✅ Brand new aftermarket replacement — not an OEM Black & Decker part
• ✅ Compact green PCB construction for easy integration into battery housings
• ✅ Ideal for battery repair, rebuild, and DIY power tool projects

Specifications

What's in the Box

• 1 × Li-Ion Battery Charging Protection Circuit Board (PCB)

⚠️ Please Read Before Purchasing

1. This product is a PCB board only — it does NOT include battery cells, a battery box, or a charger.
2. Compatible with 21700 lithium batteries only. Not suitable for 18650 lithium batteries.
3. Intended for buyers who are familiar with lithium battery performance and have practical experience in battery assembly.
4. Color may appear slightly different from images due to lighting and display settings. Measurement tolerance: ±1–3 cm.

For more on lithium battery safety, visit the U.S. Consumer Product Safety Commission or reference OSHA's Lithium Battery Safety Guidelines.

Looking for other electronics repair components or power accessories? Check out our 1/2 Inch Plastic Tap Replacement or browse our Tuya WiFi Smart Relay Switch for more DIY-friendly components.

Frequently Asked Questions

Q: Is this PCB protection board compatible with 18650 lithium battery cells?

A: No. This battery protection circuit board is designed exclusively for 21700 lithium battery cells. It is NOT compatible with 18650 cells. Using it with 18650 cells may result in improper fit or unsafe operation.

Q: Does this listing include battery cells or a battery housing?

A: No. This listing includes the PCB protection board only. Battery cells, battery box, and charger are NOT included. You will need to source 21700 Li-Ion cells and a compatible Black & Decker 20V battery enclosure separately.

Q: What does the BMS protection circuit board actually do?

A: A Battery Management System (BMS) PCB monitors and protects your lithium battery pack by preventing overcharging, over-discharging, and short circuits. It is an essential safety component for any DIY or rebuilt lithium battery pack used in power tools.

Q: Is this an official Black & Decker OEM replacement part?

A: No. This is an aftermarket replacement PCB designed to be compatible with Black & Decker 20V 21700 lithium battery packs. It is not manufactured by or affiliated with Black & Decker.

Q: Who should buy this product?

A: This product is best suited for experienced electronics hobbyists, battery repair technicians, and DIY enthusiasts who have hands-on knowledge of lithium battery assembly. If you are not familiar with lithium battery handling, we strongly advise against purchasing this item for safety reasons.