24V 6S 40A 18650 Li-Ion Lithium Battery Protection Board Solar Lighting BMS PCB with Balance Charging for E-bike Scooter

Description

The 24V 6S 40A Li-Ion BMS Protection Board is designed to manage and protect 6-series (6S) lithium-ion battery packs made from 18650 cells. It provides essential battery protection functions including overcharge, over-discharge, overcurrent, and short-circuit protection, helping protect the connected battery pack during normal charging and discharging.

This 6S BMS is suitable for a nominal 24V-class lithium-ion battery pack, with a full charging voltage of 25.5V. The board also includes a cell balancing function to help maintain more consistent voltage levels between the individual series cells during charging.

With a rated maximum continuous discharge current of 40A and an instantaneous discharge capability of up to 70A, this BMS can be used in a range of higher-current DIY battery applications, provided the battery cells, wiring, connectors, and other components are appropriately rated.

Key Features

• Designed for 6S Li-Ion battery packs
• Suitable for 18650 lithium-ion cells
• 24V-class battery system
• Maximum continuous discharge current: 40A
• Instantaneous discharge current: 70A
• Maximum charging current: 40A
• Charging voltage: 25.5V
• Built-in cell balancing function
• Balance current: 41 ± 5mA
• Overcharge protection
• Over-discharge protection
• Overcurrent protection
• Short-circuit protection
• Low working current
• Compact PCB design
• Suitable for DIY lithium battery packs

Protection Functions

Overcharge Protection

The BMS monitors the voltage of the individual lithium-ion cells. When a cell reaches the specified overcharge detection threshold of approximately 4.25V, the protection circuit can disconnect charging to help prevent continued overcharging.

• Overcharge detection: 4.25 ± 0.025V
• Overcharge delay: 1.0 ± 0.5 seconds
• Overcharge release: 4.15 ± 0.05V

Over-Discharge Protection

The board also monitors cell voltage during discharge. If a cell falls below the specified over-discharge threshold, the BMS can disconnect the load to help protect the battery from excessive discharge.

• Over-discharge detection: 2.7 ± 0.1V
• Detection delay: 1.0 ± 0.5 seconds
• Release voltage: 3.0 ± 0.1V

Overcurrent Protection

The BMS provides protection against excessive current draw. The specified overcurrent detection threshold is approximately 75 ± 5A, with a detection delay of approximately 1 ± 0.3 seconds.

After an overcurrent event, the load should be disconnected to allow the protection circuit to recover.

Short-Circuit Protection

The board includes short-circuit protection that responds rapidly when an external load creates a short circuit.

• Short-circuit detection delay: 250µs
• Recovery condition: Disconnect the load

Battery Cell Balancing

The integrated balancing function helps equalize the voltage of the six series-connected cells during charging. Cell balancing is important for multi-cell lithium battery packs because individual cells can gradually develop different voltage levels.

• Balance detection voltage: 4.125 ± 0.025V
• Balance release voltage: 4.125 ± 0.05V
• Balance current: 41 ± 5mA

6S Battery Pack Configuration

This BMS is intended for a 6S lithium-ion battery configuration, meaning six groups of lithium-ion cells are connected in series.

For standard 3.7V nominal Li-Ion cells:

6 × 3.7V = approximately 22.2V nominal

When fully charged:

6 × 4.2V = 25.2V

The listed BMS charging voltage is 25.5V, so use a compatible charging setup and follow the battery manufacturer’s recommended charging specifications.

Specifications