Description

Lithium Battery Charger Protection Module (BMS) 4S 20A 16.8V

The Lithium Battery Charger Protection Module (BMS) 4S 20A 16.8V is a high-performance battery management system designed specifically for 4-cell lithium-ion (Li-ion) and lithium-polymer (Li-Po) battery packs. Built to ensure safety, reliability, and long battery life, this protection board provides advanced protection against overcharge, over-discharge, overcurrent, short circuit, and voltage imbalance.

Ideal for DIY battery pack builders, electric vehicle projects, solar storage systems, and portable power solutions, this 4S 20A BMS ensures your 16.8V lithium battery pack operates efficiently and safely under various load conditions.

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🔋 What is a 4S 16.8V Lithium BMS?

A 4S BMS (Battery Management System) is designed to manage four lithium cells connected in series. Each lithium-ion cell typically has:

• Nominal voltage: 3.7V

• Fully charged voltage: 4.2V

For a 4-cell pack:

• Nominal voltage: 14.8V

• Fully charged voltage: 16.8V (4 × 4.2V)

This module supports 20A continuous discharge current, making it suitable for medium to high power applications.

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⚙️ Key Features of 4S 20A 16.8V Lithium BMS

✅ 1. Comprehensive Protection System

This BMS board includes intelligent multi-layer protection:

• Overcharge Protection
  Automatically disconnects charging when any cell reaches approximately 4.2V.

• Over-Discharge Protection
  Cuts off output when any cell drops below safe voltage levels (around 2.7–3.0V).

• Overcurrent Protection (20A Continuous)
  Prevents excessive current that could damage cells or connected devices.

• Short Circuit Protection
  Instantly disconnects the battery output in case of a short circuit.

• Automatic Recovery Function
  Restores operation once fault conditions are removed.

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✅ 2. High Current Handling – 20A Continuous

With a 20A continuous discharge rating, this module is perfect for:

• Electric bicycles (low to mid power)

• Electric scooters

• Solar energy storage packs

• Portable power banks

• Robotics and automation systems

• LED lighting systems

• DIY power tool battery packs

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✅ 3. Stable Charging & Discharging Performance

Designed with high-quality MOSFET components, the module offers:

• Low internal resistance

• Minimal heat generation

• Stable output voltage

• Efficient power management

This ensures reliable performance even under heavy load conditions.

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✅ 4. Compact & Easy Installation

The module is designed with clearly labeled terminals:

• B+ – Battery positive

• B- – Battery negative

• B1, B2, B3 – Cell balance connections

• P+ / P- – Load and charger terminals

Its compact PCB design makes it easy to integrate into custom battery packs.

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📊 Technical Specifications

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🔧 Applications

The 4S 20A 16.8V Lithium BMS is widely used in:

• 🔋 14.8V / 16.8V Lithium battery packs

• 🛴 Electric scooters

• 🚲 E-bikes (low power systems)

• 🔆 Solar storage systems

• 🤖 Robotics projects

• 💡 Emergency lighting backup

• 🔌 Portable power stations

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🚀 Why Choose This 4S 20A Lithium BMS?

✔ Enhanced Battery Safety

Protects against common lithium battery failures such as overcharging and deep discharge.

✔ Extended Battery Life

Prevents voltage imbalance and cell damage, improving overall battery performance.

✔ High Load Capability

Handles up to 20A continuous current, suitable for demanding applications.

✔ Cost-Effective & Reliable

Ideal for battery repair shops, manufacturers, and DIY enthusiasts.

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🛠 Installation Instructions

1. Connect B- to battery pack negative.

2. Connect cell junction wires to B1, B2, B3 in sequence.

3. Connect B+ to battery pack positive.

4. Connect charger and load to P+ and P- terminals.

5. Double-check wiring and polarity before powering on.

⚠ Improper connection may permanently damage the module. Ensure correct wiring order.

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📦 Package Includes

• 1 × Lithium Battery Charger Protection Module (BMS) 4S 20A 16.8V