21V 100A 21700 Li-ion Battery Case Kit with BMS & LED Display

Build your own high-performance 21V lithium-ion battery pack with this versatile 21700 battery case kit — designed for power tool compatibility with 5, 10, or 15-cell configurations. Featuring a robust BMS (Battery Management System) board, LED power display, and 4 MOSFETs, this DIY battery housing gives you a reliable, customizable energy solution for your workshop tools.

Note: This is a battery case/holder kit only — batteries are not included. You supply your own 21700 lithium cells (5, 10, or 15 cells depending on your chosen configuration) to assemble the pack. No after-sales service is included with this kit.

Key Features

• Flexible Cell Configuration: Supports 5-cell, 10-cell, or 15-cell 21700 lithium battery arrangements to suit different capacity needs
• 21V / 100A Output: High-current BMS circuitry handles demanding power tool loads with confidence
• Built-in BMS Protection: Battery Management System with 4 MOSFETs provides overcharge, over-discharge, and short-circuit protection
• LED Power Display: Real-time battery level indicator keeps you informed at a glance
• Durable Construction: Plastic + metal housing built to withstand the rigors of workshop and job-site use
• 3 Color Options: Choose the finish that suits your style or tool setup
• Power Tool Compatible: Designed to fit Makita-style tool interfaces

Specifications

• Voltage: 21V
• Maximum Current: 100A
• Cell Compatibility: 21700 Li-ion cells
• Cell Configurations: 5S / 10S / 15S (5, 10, or 15 cells)
• BMS: Included (4 MOSFET design)
• Display: LED power indicator
• Material: Plastic + Metal
• Colors Available: 3 options
• Batteries Included: No — user-supplied 21700 cells required

What's in the Box

• 1× Battery case/housing kit (plastic + metal shell)
• 1× BMS PCBA board with 4 MOSFETs
• 1× LED power display module
• Assorted connection hardware

For guidance on safe lithium battery handling and assembly best practices, refer to the U.S. Consumer Product Safety Commission – Lithium Battery Safety resources.

Learn more: Battery pack

Frequently Asked Questions

Q: What does this 21700 battery case kit include?

A: This kit includes the plastic and metal battery case housing, a BMS (Battery Management System) PCBA board with 4 MOSFETs, an LED power display module, and assembly hardware. 21700 lithium cells are not included — you need to supply your own 5, 10, or 15 cells depending on the configuration you choose.

Q: Which power tools is this 21V battery case compatible with?

A: This battery case is designed to be compatible with Makita-style 21V power tool interfaces, making it a great DIY option for assembling a custom replacement or backup battery pack for cordless drills, saws, and other compatible tools.

Q: Is it safe to assemble a lithium battery pack at home?

A: This kit is intended for users with experience in DIY electronics and lithium battery assembly. The built-in BMS provides important protections (overcharge, over-discharge, short-circuit), but proper handling of lithium cells is essential. Always follow lithium battery safety guidelines and ensure cells are matched in capacity and charge state before assembly.

Q: What cell configurations does this case support?

A: The case supports three configurations: 5-cell (5S), 10-cell (10S), and 15-cell (15S) using 21700 format lithium-ion batteries, allowing you to build packs with different capacity outputs to suit your tool's requirements.