3S 50A 21V Lithium BMS Board MT5S for Power Tools & E-Bikes
3-Series 50A 21V Lithium Battery BMS Protection Board – MT5S Module
Upgrade your battery pack with this compact yet powerful 3-Series (3S) 50A 21V Lithium Battery BMS Board (MT5S Module). Engineered for demanding applications including power tools, electric bikes, and DIY battery pack builds, this PCB protection board delivers reliable charge/discharge management with multi-layer safety features built right in. Made in Mainland China.
Key Features
- Multi-Protection Circuit: High-precision protection against overcharge, over-discharge, and short circuits — keeping your battery pack and equipment safe at all times.
- 50A Instant Start Current: Handles up to 50A instantaneous output, delivering robust performance for high-power tools and equipment.
- Balanced Charge/Discharge: Built-in cell balancing ensures all cells charge and discharge evenly, extending overall battery pack lifespan.
- Wide Compatibility: Designed for 3S lithium battery configurations (21V fully charged); ideal for angle grinders, wrenches, e-bikes, and a wide range of power tools.
- Excellent Heat Dissipation: High-quality PCB material and alloy construction provide superior thermal management for long-term, stable operation.
- Compact Size: Measures just 46 × 40 mm (approx. 1.81 × 1.57 in), making it easy to fit into custom battery housings and enclosures.
Specifications
| Module Type | MT5S BMS Protection Board |
| Series | 3S (3-Series) |
| Rated Voltage | 21V (fully charged) |
| Max Continuous Current | 50A |
| Material | PCB / Alloy |
| Dimensions | 46 × 40 mm / 1.81 × 1.57 in |
| Battery Included | No |
| Country of Origin | Made in Mainland China |
Package Includes
- 1 × 3S 50A 21V BMS Protection Board (MT5S Module)
Notes
- Photos are for reference only; please refer to specifications for exact dimensions.
- Allow slight variation due to manual measurement.
- Screen calibration may cause minor color differences from the actual product.
- Batteries are not included.
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Frequently Asked Questions
Q: What battery configuration is this BMS board designed for?
A: This BMS board is designed for 3-Series (3S) lithium battery packs, which have a fully charged voltage of 21V. It is compatible with standard 18650 and similar 3S lithium cell configurations commonly used in power tools and e-bikes.
Q: Does this board support cell balancing?
A: Yes, the MT5S module features built-in cell balancing during charging, ensuring all cells in your 3S pack charge evenly to maximize capacity and extend battery life.
Q: Is this BMS board suitable for e-bikes?
A: Absolutely. With a 50A instant current rating and multi-protection features, this board is well-suited for e-bike battery packs, angle grinders, cordless wrenches, and other high-power applications.
Q: Are batteries included with this purchase?
A: No, batteries are not included. This listing is for the BMS protection board only. You will need to source your own 3S lithium cells separately.
Production & Packaging Notice
To maintain high stock availability and fast shipping times, our items are sourced from multiple verified manufacturing facilities. While the core quality, materials, and product specifications remain identical, you may notice slight variations in the packaging design, manufacturing origin, or the wording of the printed instructions.