7S 24V 15A Lithium Battery Protection Board

The 7S 24V 15A Lithium Battery Protection Board (BMS) is an electronic system designed to manage and protect a 7-series (7S) lithium-ion battery pack with a nominal voltage of 24V and a continuous discharge current of 15A. These boards are essential for maintaining battery health, preventing hazardous conditions like overcharging or short-circuiting, and ensuring all cells in the pack stay balanced. 

Key Specifications:

• Voltage Support: Designed for 7 strings of 3.6V/3.7V Li-ion cells, with a nominal voltage of 24V-25.9V and a full charge voltage of 29.4V-30V.
• Current Ratings: Provides a continuous discharge current of 15A. Some models support instantaneous peak currents up to 25A-60A depending on the specific design.
• Internal Resistance: Often rated at ≤20mΩ to ≤30mΩ to minimize heat generation during high-load operations.
• Operating Temperature: Typically operates between -30°C and +80°C.

Protective Functions:

The board acts as a "guardian" for the battery pack by monitoring each cell individually.

• Overcharge Protection: Automatically cuts off the circuit if any cell exceeds a safe voltage (usually 4.25V ± 0.05V).
• Over-discharge Protection: Stops the discharge if cell voltage drops below a safe limit (typically 2.5V-2.7V).
• Short Circuit & Overcurrent Protection: Instantly disconnects the load if a short circuit or current surge is detected to prevent fire or cell damage.
• Cell Balancing: Most models, like the ANN 7M15A, include a balancing function (often 30mA-40mA) that equalizes voltage across all 7 cells during charging to prolong battery lifespan.
• Temperature Monitoring (NTC): Higher-end versions include an NTC temperature sensor to shut down the system if it overheats, commonly at thresholds around 70°C for discharge and 50°C for charging. 

Common Applications:

These boards are frequently used in medium-power 24V systems, including:

• Electric Vehicles: E-bikes, scooters, and wheelchairs.
• Energy Storage: Small solar power systems and UPS battery packs.
• Power Tools: DIY battery pack repairs or custom-built power tools.