21V 18650 Battery Protection Board for Makita – 6MOS 30A/5MOS 25A

Makita 18650 Battery Protection Circuit Board – 21V Replacement

Keep your Makita 18650 lithium battery packs running safely and reliably with this high-quality 21V Battery Protection Board. Available in two configurations — 6MOS 30A and 5MOS 25A — this replacement BMS (Battery Management System) circuit board features a 5-string cell layout, alloy copper hardware, and built-in temperature control for comprehensive battery protection.

Whether you're rebuilding a worn-out Makita power tool battery or upgrading an existing pack, this CE-certified board delivers over-charge, over-discharge, over-current, and short-circuit protection to extend the life of your battery cells and protect your tools.

Made in Mainland China.

Key Features

• Compatible with Makita 18650 battery packs — ideal replacement for DIY battery rebuilds
• Two configurations available: 6MOS 30A (higher current) or 5MOS 25A
• 5-string (5S) large board design — supports 21V nominal lithium-ion packs
• Temperature control protection — prevents thermal runaway and overheating
• Alloy copper hardware — for low resistance and reliable high-current performance
• CE Certified — meets European safety and electromagnetic compatibility standards
• Protects against: overcharge, over-discharge, overcurrent, and short circuit
• Low voltage range: below 75V DC / below 50V AC

Specifications

What's in the Box?

• 1 × 21V 18650 Battery Protection Circuit Board (your choice of 6MOS 30A or 5MOS 25A)

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For general guidance on lithium battery safety standards and best practices, refer to the U.S. Consumer Product Safety Commission – Lithium-Ion Battery Safety.

Learn more: Printed circuit board

Frequently Asked Questions

Q: Which Makita battery packs is this 21V protection board compatible with?

A: This 21V 5-string (5S) lithium-ion battery protection board is designed to be compatible with Makita 18650 cell battery packs that operate at a 21V nominal voltage. It is commonly used in DIY battery rebuilds for Makita 18V/21V power tool batteries. Always verify the cell count and layout of your specific pack before installation.

Q: What is the difference between the 6MOS 30A and 5MOS 25A versions?

A: The 6MOS 30A version uses six MOSFET switches and supports a higher continuous discharge current of 30A, making it better suited for high-drain power tools. The 5MOS 25A version uses five MOSFETs and handles up to 25A, suitable for moderate-demand applications. Choose based on the peak current requirements of your power tool.

Q: Does this protection board include over-temperature protection?

A: Yes. This board features built-in temperature control, which monitors the battery's thermal state and cuts off the circuit if temperatures exceed safe limits — helping prevent thermal runaway, battery damage, and potential safety hazards.

Q: Is any soldering required for installation?

A: Yes, installing a battery protection board typically requires soldering skills and the appropriate tools. It is recommended for users with experience in electronics repair or battery rebuilding. If you are unsure, consult a qualified technician.