4S 40A 18650 Balanced BMS with Protection Board

The 4S 40A 18650 Battery Management System (BMS) with protection and balancing is designed to efficiently manage and safeguard 4-series (4S) lithium-ion battery packs, commonly built using 18650 cells. It ensures safe operation by balancing cell voltages, preventing overcharge, over-discharge, overcurrent, and short-circuit conditions. Compact, durable, and reliable, this BMS is perfect for high-power applications such as electric vehicles, power tools, and energy storage systems.

Key Features

• Supports 4-Series (4S) Lithium-Ion Packs: Designed for 18650 or similar Li-ion cells
• High Current Capacity: Supports up to 40A continuous discharge current
• Active Balancing: Maintains equal charge levels across all cells for maximum efficiency
• Comprehensive Protection:
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  • Overcharge protection
  • Over-discharge protection
  • Overcurrent and short-circuit protection
  • Temperature protection for enhanced safety
• Efficient & Compact: Lightweight, space-saving design suitable for integration into battery packs
   

Specification

• Battery Configuration: 4S (4-series) lithium-ion
• Continuous Discharge Current: 40A
• Overcharge Protection Voltage: 4.25V ±0.05V per cell
• Overdischarge Protection Voltage: 2.8V ±0.05V per cell
• Balance Voltage: 4.2V ±0.05V per cell
• Balance Current: 30mA (typical)
• Overcurrent Protection: Activated at 60A ±5A
• Short-Circuit Protection: Yes
• Operating Temperature Range: -20°C to +60°C
• Dimensions / Weight: Varies by manufacturer

Application

• Electric Vehicles: Battery protection for e-bikes, e-scooters, and small EVs
• Power Tools: Ensures safe operation of high-current cordless tools
• Energy Storage Systems: Ideal for solar and renewable energy storage packs
• Portable Electronics: Suitable for high-capacity lithium-ion battery banks

Usage Instructions

• Connect the BMS to the battery pack following the manufacturer’s wiring diagram
• Ensure secure and insulated connections to prevent short circuits
• Install in a well-ventilated area to aid heat dissipation
• During initial operation, monitor temperature and cell voltages to confirm proper function
• Periodically inspect wiring and components for maintenance and safety

Caution

• Always follow the correct wiring sequence — incorrect connection can damage the BMS or battery pack
• Do not exceed rated current or voltage limits
• Avoid exposure to moisture, extreme heat, or physical damage
• Maintain good ventilation during high-load use