21700 Lithium Battery BMS Circuit Board for Power Tools
21700 Lithium Battery BMS Circuit Board for Power Tools
21700 Lithium Battery BMS Circuit Board for Power Tools
Keep your power tools running at peak performance with this precision-engineered 21700 Lithium Battery BMS (Battery Management System) Circuit Board. Designed as a replacement or upgrade PCB for 21V lithium battery packs used in a wide range of power tools, this board ensures stable current flow, balanced charging, and reliable battery operation — every time you reach for your tools.
Whether you're rebuilding a worn battery pack or upgrading an existing setup, this compact yet capable board is an excellent value for DIY enthusiasts, technicians, and professionals alike.
Key Features
- Compatibility: Designed for 21700 cell lithium battery packs, compatible with brands including Lomvum, Zhipu, Hongsong, and similar 21V power tool battery systems
- Board Material: High-quality PCB (Printed Circuit Board) construction for durability and heat resistance
- Dimensions: 98 × 60 mm (3.86 × 2.36 in) — compact form factor for easy installation
- BMS Function: Manages charge/discharge cycles to help maintain battery longevity and consistent output
- No Overcurrent Cutoff During Tool Operation: The "no protection" configuration allows the high-drain demands of power tools to be met without mid-task interruption
- Easy Integration: Drop-in replacement for compatible battery pack housings
Specifications
| Cell Type | 21700 Lithium |
| Voltage | 21V |
| Board Size | 98 × 60 mm / 3.86 × 2.36 in |
| Material | PCB |
| Type | BMS (Battery Management System) |
| Compatible Brands | Lomvum, Zhipu, Hongsong, and similar 21V tools |
Who Is This For?
This BMS board is ideal for:
- DIY hobbyists rebuilding or repairing lithium battery packs
- Electronics technicians and repair professionals
- Power tool users looking to extend the life of their battery packs
- Anyone needing a cost-effective replacement circuit board for compatible 21V tool batteries
Safe Handling Notice
When working with lithium battery components, always follow proper electrical safety practices. For guidance on safe battery handling, refer to the U.S. Consumer Product Safety Commission (CPSC) Lithium Battery Safety resources.
Frequently Asked Questions
Q: What does a BMS circuit board do in a lithium battery pack?
A: A BMS (Battery Management System) circuit board monitors and manages the charge and discharge cycles of lithium cells in a battery pack. It helps balance cell voltages, regulate current flow, and protect against overcharging — keeping your battery pack operating efficiently and extending its overall lifespan.
Q: Is this BMS board compatible with my power tool battery?
A: This board is designed for 21700-cell lithium battery packs operating at 21V, and is compatible with brands including Lomvum, Zhipu, and Hongsong. We recommend verifying your battery pack's cell type and dimensions (98 × 60 mm) before purchasing to ensure a proper fit.
Q: Why does this board have "no protection" in the description?
A: The "no protection" designation refers to the absence of a hard over-current cutoff circuit. Power tools draw very high current on startup and under load, so this board is configured to allow those high-drain demands without tripping a cutoff — making it ideal for power tool applications where uninterrupted current flow is essential.
Q: How large is the circuit board and how do I install it?
A: The board measures 98 × 60 mm (3.86 × 2.36 in). Installation typically involves opening the battery pack housing, disconnecting the old board, and connecting the replacement following the original wiring layout. Always discharge the battery fully and observe proper electrical safety precautions before working with battery components.