2S 20A BMS Board 7.4V 8.4V 18650 Lithium Battery Protection
2S 20A BMS Board 7.4V 8.4V 18650 Lithium Battery Protection
2S 20A BMS Board – 7.4V / 8.4V 18650 Lithium Battery Protection Circuit
Keep your DIY lithium battery packs safe and performing at their best with this 2S 20A Battery Management System (BMS) protection board. Designed for 2-cell series 18650 lithium packs at 7.4V (nominal) / 8.4V (fully charged), this compact board guards against overcharge, over-discharge, and short-circuit conditions — making it an essential component for e-bikes, power tools, RC projects, portable power banks, and more.
Available in both Standard and Balance variants, so you can choose the version that best suits your build requirements. The balance version actively equalises cell voltages for longer pack life and more consistent performance.
Key Features
- 2S Configuration: Supports two 18650 lithium cells in series
- 20A Continuous Discharge Current: Handles demanding loads in DIY applications
- Nominal Voltage: 7.4V | Charging Voltage: 8.4V – 9.0V
- Overcharge Protection: Cuts off charging when cells reach maximum safe voltage
- Over-Discharge Protection: Disconnects load before cells drop to damaging levels
- Short-Circuit & Overcurrent Protection: Instantly cuts power on fault detection
- Balance Version Available: Keeps individual cell voltages matched for optimal pack health
- Compact PCB Design: Easy to integrate into custom battery housings
- Compatible With: 18650, and equivalent 2S lithium-ion cell configurations
- Made in Mainland China
Specifications
| Cell Configuration | 2S (2 cells in series) |
| Rated Current | 20A |
| Nominal Pack Voltage | 7.4V |
| Charging Voltage | 8.4V – 9.0V |
| Compatible Cells | 18650 Lithium-Ion |
| Type | Standard / Balance (select your variant) |
| Condition | New |
Ideal For
- DIY lithium battery packs and rebuilds
- E-bike and scooter battery management
- Power tool battery replacements
- Portable power banks and UPS systems
- RC vehicles, robots, and electronics projects
- Solar energy storage and off-grid projects
Related Products You Might Like
- Air Compressor Pressure Gauge 0-10/0-12/0-25 Bar | DIY Tool
- Electromagnetic Induction Tester – Coil & Circuit Fault Detector
Learn more: ENERGY STAR product efficiency guidance
Frequently Asked Questions
Q: What does a 2S BMS protection board do for my lithium battery pack?
A: A 2S BMS (Battery Management System) board monitors and protects your two-cell lithium battery pack. It prevents overcharging, over-discharging, and short-circuit events that could damage your cells or create a safety hazard. This makes it a must-have component for any DIY 18650 lithium battery project operating at 7.4V / 8.4V.
Q: What is the difference between the Standard and Balance versions?
A: The Standard BMS board provides core protection functions — overcharge, over-discharge, and short-circuit cutoff. The Balance version adds an active cell-balancing circuit that equalises the voltage of each individual cell during charging. This extends the overall lifespan of your 2S lithium pack and ensures more consistent performance across charge cycles.
Q: What charging voltage does this BMS board support?
A: This 2S BMS protection board supports a charging input voltage of 8.4V to 9.0V, which is the standard range for fully charging a 2-cell series 18650 lithium-ion pack. Always use a compatible lithium charger to ensure safe operation.
Q: Is this board compatible with all 18650 lithium cells?
A: Yes, this board is designed for use with standard 18650 lithium-ion cells wired in a 2S (two-cell series) configuration. It is suitable for most reputable 18650 cells commonly used in DIY battery builds, provided the discharge current does not exceed the rated 20A continuous limit.