FMA 7S 25.9V 20A/70A Li-Po Li-ion Battery Management System Protection Board BMS PCM

FMA 7S 25.9V Li-ion Battery Protection Circuit Board (BMS/PCM)

Professional-grade Battery Management System (BMS) protection circuit board designed for 7S lithium-ion and lithium-polymer battery packs. Provides comprehensive protection against overcharge, over-discharge, overcurrent, and short circuit conditions with active cell balancing to ensure safe and reliable battery operation.

Key Features

• 7S Configuration: Designed for 7-cell series lithium battery packs (25.9V nominal, 29.4V fully charged)
• Multi-Protection: Overcharge, over-discharge, overcurrent, and short circuit protection
• 20A Continuous Current: Supports up to 20A continuous discharge current
• 15A Charging Current: Supports up to 15A continuous charging current
• Active Cell Balancing: 100mA ± 25mA balance current per cell for optimal battery performance
• Low Power Consumption: ≤11μA standby current for minimal battery drain
• Compact Size: 9mm × 34mm × 59mm for easy integration
• Wide Temperature Range: Operating temperature -40°C to +85°C

Package Contents

• 1× FMA 7S BMS Protection Circuit Board

Technical Specifications

1. FPML07S200D

2. FPML07S700F95

Applications

• 7S lithium-ion battery pack protection
• E-bike and electric scooter battery systems
• Power tool battery pack assemblies
• Portable power stations
• LED lighting systems
• Medical equipment battery packs
• Custom battery pack projects
• DIY battery rebuilds and upgrades

Protection Functions

Overcharge Protection: Automatically disconnects charging when any cell reaches 4.325V ± 0.025V, preventing battery damage from excessive voltage. The protection releases when voltage drops to 4.15V ± 0.05V per cell.

Over-discharge Protection: Cuts off discharge when any cell voltage drops to 2.8V ± 0.05V, preventing deep discharge that can permanently damage lithium cells. Protection releases at 3.0V ± 0.05V per cell.

Overcurrent Protection: Monitors discharge current and disconnects the load if current exceeds 55.5A ± 4A for more than 9ms, protecting both the battery and connected devices. Release by cutting the load.

Short Circuit Protection: Instantly disconnects the battery within 320μs in the event of a short circuit, preventing fire hazards and equipment damage. Release by cutting the load.

Cell Balancing: Active balancing function with 100mA ± 25mA current per cell ensures all cells maintain equal voltage levels during charging, maximizing battery capacity and lifespan.

Installation & Wiring

Before Installation:

• Ensure all battery cells are balanced and at similar voltage levels (within 0.1V)
• Verify that the battery pack voltage matches the BMS specification (7S configuration)
• Prepare necessary tools: soldering iron, wire strippers, multimeter, heat-shrink tubing
• Work in a clean, well-ventilated area with proper ESD protection
• Wear safety glasses and insulated gloves

Wiring Guidelines:

• Connect balance wires to each cell in the correct sequence (B0 to B7, refer to product images)
• Use appropriate wire gauge for main power connections (minimum 14AWG for 20A)
• Double-check polarity before making final connections (positive to P+, negative to P-)
• Ensure all solder joints are clean and secure with good electrical contact
• Insulate all connections with heat-shrink tubing to prevent shorts
• Test voltage at each balance point with a multimeter before powering on
• Verify total pack voltage is within expected range (25.9V-29.4V)

Required Skills:

• Understanding of lithium battery chemistry and safety
• Proficiency in soldering and electrical connections
• Ability to read wiring diagrams and follow technical specifications
• Knowledge of proper battery handling and safety protocols
• Experience with multimeter usage and voltage testing

Who Should NOT Attempt Installation:

• Individuals without electrical or electronics experience
• Those unfamiliar with lithium battery safety requirements
• Anyone without proper tools or workspace
• Minors without qualified adult supervision
• If unsure about any aspect of installation, consult a professional technician

Important Notes

Connector Customization: We ship the standard configuration as shown in the main product images. If you require specific connectors or custom wire arrangements, please refer to the product gallery images and contact us with your requirements before ordering.

Compatibility: This BMS is designed for 7S lithium-ion or lithium-polymer battery packs with nominal voltage of 25.9V. Ensure your battery configuration matches before purchase. Using this BMS with incorrect battery configurations can result in improper protection and potential safety hazards.

Testing: After installation, perform thorough testing including voltage checks at all balance points, charge/discharge cycles, and protection function verification before putting the battery pack into regular use.

Why Choose FMA BMS Products?

FMA specializes in high-quality battery management solutions for lithium-ion and lithium-polymer battery systems. Our BMS boards are manufactured using premium components and undergo rigorous quality control testing to ensure reliable protection and long service life. Each board is inspected and tested before shipment to guarantee it meets our strict quality standards. With low MOSFET resistance (≤12mΩ), active cell balancing, and wide operating temperature range, our BMS boards deliver professional-grade performance for demanding applications.

Custom BMS Solutions

Need a different cell configuration, current rating, or custom features? We offer custom BMS design and manufacturing services. Contact us with your specifications including cell count, voltage requirements, current ratings, and any special features you need, and we'll create a tailored solution for your application.

Safety Information

Charging: Use only chargers designed for 7S lithium battery packs with proper voltage (29.4V) and current specifications (maximum 15A). Never exceed the maximum charging voltage.

Storage: Store in a cool, dry place away from direct sunlight, heat sources, and flammable materials. Keep out of reach of children.

Operation: Do not bypass or disable protection functions. Do not expose to water, moisture, or conductive materials that could cause short circuits.

Temperature: Operate within recommended temperature range (-40°C to +85°C). Avoid extreme temperatures during charging and discharging.

Disposal: Dispose of according to local regulations for electronic waste. Do not incinerate or dispose of in regular trash.

Inspection: Regularly inspect for signs of damage, overheating, or component failure. Discontinue use immediately if any abnormalities are detected.

Shipping & Transportation Notice

Hazardous Material: This product is designed for use with lithium batteries and may be subject to shipping restrictions.

Air Transport Restrictions: Due to international air transport regulations, shipments may be subject to additional restrictions and longer transit times.

Packaging Compliance: All shipments comply with applicable packaging requirements for electronic components.

Delivery Time: Electronic component parcels may experience extended delivery times due to customs inspections and carrier handling procedures.

Documentation: Proper documentation accompanies all shipments to ensure compliance with international shipping regulations.