21V BMS Battery Case for 18650 Power Tools – Storage Box
21V BMS Battery Case for 18650 Power Tools – Storage Box
21V BMS Battery Storage Case for 18650 Li-Ion Cells
Build your own high-performance 21V lithium battery pack for cordless power tools with this BMS (Battery Management System) storage case. Designed for 10S 18650 cell configurations, this compact housing pairs with a dedicated BMS protection board to deliver stable, reliable power for angle grinders, cutting tools, and other wireless electric power tools. Note: Batteries and charger are NOT included.
⚠️ Important: Always charge using a 21V DC lithium battery charger. Do not charge through the discharge port.
Key Features
- 10S Li-Ion BMS Compatible: Uses a dedicated IC for 10-series 18650 lithium batteries to monitor real-time voltage, charge/discharge current, and ambient temperature.
- Multi-Layer Protection: Built-in overcharge protection, over-discharge protection, and short-circuit protection for safer, longer-lasting battery operation.
- Ultra-Low Power Consumption: Working current ~25µA; quiescent current ~6µA — extends overall battery life.
- Continuous Discharge Current: 8–20A continuous discharge output, suitable for demanding power tool applications.
- Charge Voltage: 21V total; 4.25V per single cell charge voltage.
- Nickel Strip Thickness: 0.15mm for reliable cell connections.
- Compact Black Housing: Dimensions: 4.53 × 2.87 × 2.56 in (11.5 × 7.3 × 6.5 cm). Easy to integrate into DIY power tool builds.
Specifications
| Charge Voltage | 21V (4.25V per cell) |
| Discharge Current | 8–20A continuous |
| Working Current | ~25µA |
| Quiescent Current | ~6µA |
| Nickel Thickness | 0.15mm |
| Dimensions | 11.5 × 7.3 × 6.5 cm / 4.53 × 2.87 × 2.56 in |
| Color | Black |
| Battery Included | No |
| Charger Included | No |
| Origin | Made in Mainland China |
What's in the Box?
- 1× BMS 21V Power Tool Battery Case/Storage Box Set
Note: Minor component variations (e.g. resistors or diodes) may occur as part of ongoing product improvements and do not affect performance or function.
Related Products You May Like
- Air Compressor Pressure Gauge 0-10/0-12/0-25 Bar | DIY Tool
- Electromagnetic Induction Tester – Coil & Circuit Fault Detector
- 360° Bicycle Chain Cleaner Tool | Bike Gear Cleaning Kit
Learn more: OSHA guidance on hand and power tools
Frequently Asked Questions
Q: Does this 21V BMS battery case come with 18650 batteries or a charger?
A: No — this listing is for the battery storage case/housing and BMS board only. You will need to source compatible 18650 lithium cells and a 21V DC lithium battery charger separately to complete your battery pack build.
Q: What power tools is this 21V BMS battery storage box compatible with?
A: This case is designed primarily for cordless/wireless electric power tools such as angle grinders and cutting tools that operate on a 21V lithium battery pack. It is ideal for DIY battery pack builders using 10-series 18650 cells.
Q: What protection features does this BMS battery case include?
A: The integrated BMS board provides overcharge protection, over-discharge protection, and short-circuit protection. It continuously monitors cell voltage, charge/discharge current, and ambient temperature to help extend battery longevity and maintain safe operation.