4S 40A Enhance BMS – KSH 650 at HIMASTORES Mombasa – best electronics in Kenya
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4S 40A Enhance BMS

SKU: HMJ618 Category: Batteries and powerbanks
KSH 650.00
Out of Stock

Product Description

4S 40A Enhanced BMS Lithium Battery Protection Board

HighPerformance Battery Management System for 4Cell Li-ion Packs

The 4S 40A Enhanced BMS is a robust battery management system designed to protect and balance 4series lithiumion battery packs. Featuring 40A continuous discharge current and 100mA balancing current, this board provides comprehensive protection against overcharge, overdischarge, overcurrent, and short circuits. Perfect for power tools, electric drills, ebikes, and portable power supplies.

Designed for 3.6V/3.7V Liion and LiPo battery cells (18650, 26650, polymer)
Supports 4S configuration with 16.8V full charge voltage
Not suitable for LiFePO4 batteries Liion/Li-Po only

Technical Specifications

ParameterValue
Battery Configuration4S (4 cells in series)
Supported Battery TypesLiion / LiPo (3.6-3.7V cells)
Full Charge Voltage16.8V
Continuous Discharge Current40A (enhanced version)
Continuous Charge CurrentUp to 20A
Peak Discharge Current80-120A (depending on version)
Balancing Current100mA (passive balancing)
Overcharge Protection4.25-4.35V per cell
Over-discharge Protection2.3-3.0V per cell
Short Circuit ProtectionYes (auto recovery)
Static Current< 30-40uA
Board Dimensions~60 x 45 x 4mm
MountingThrough-hole pads

= Key Features =

Enhanced Current Capacity - 40A continuous discharge with peak support up to 120A for demanding applications

Passive Cell Balancing - 100mA balance current ensures cells remain at equal voltage for extended battery life and performance

Comprehensive Protection Overcharge, overdischarge, overcurrent, and short circuit protection with auto recovery

Low SelfConsumption Only 30-40uA static current minimizes battery drain during idle periods

Wide Application Range Supports electric drills, ebikes, power tools, LED lights, and low-power inverters

Auto Recovery - After short circuit or overcurrent protection, automatically recovers when load is removed

= Applications =

  • Power tools (electric drills, screwdrivers, sprayers)
  • E-bikes and electric scooters
  • Portable power supplies and generators
  • LED lighting systems
  • Low-power inverters and solar systems
  • DIY battery pack builds
  • Power banks and backup systems
  • Industrial and automation equipment

Wiring Guide

ConnectionDescription
B+ (Battery Positive)Positive terminal of cell 4
B1Positive terminal of cell 1 (balance wire)
B2Positive terminal of cell 2 (balance wire)
B3Positive terminal of cell 3 (balance wire)
B- (Battery Negative)Negative terminal of cell 1
P+ (Load/Charger Positive)Positive output/charge input
P- (Load/Charger Negative)Negative output/charge input

> Connect in series: Cell 1: B- to B1, Cell 2: B1 to B2, Cell 3: B2 to B3, Cell 4: B3 to B+

Use appropriate gauge wire for 40A current (minimum 8-10 AWG)
Connect balance wires in strict order: B- then B1 then B2 then B3 then B+

How It Works

The 4S 40A BMS protects your battery pack through multiple mechanisms:

  1. *Overcharge Protection*: Detects when any cell exceeds 4.25-4.35V and disconnects charging
  1. *Overdischarge Protection*: Disconnects the load when any cell drops below 2.33.0V to prevent cell damage
  1. *Overcurrent Protection*: Monitors current flow and disconnects during short circuits or excessive loads
  1. *Cell Balancing*: Equalizes cell voltages during charging to maintain pack health and maximize capacity
  1. *Auto Recovery*: After a fault condition is resolved, the BMS automatically reconnects the circuit
The BMS uses passive balancing discharges highervoltage cells through resistors to match lower-voltage cells
For optimal performance, use matched cells with similar internal resistance and capacity
The board will not function if balance wires are connected incorrectly - follow wiring order carefully

Installation Tips

  1. *Cell Matching*: Use cells from the same batch with similar voltage before assembly
  2. *Balance First*: Connect all balance wires in correct order before connecting main leads
  3. *Awaken BMS*: After wiring, connect a charger to activate the BMS before first use
  4. *Heat Management*: For continuous high-current operation, ensure adequate cooling and airflow
  5. *Wire Gauge*: Use thick wires for main power connections to handle 40A current
Before assembly, ensure all cells have similar voltage (within 0.1V) for optimal balancing
Mount the BMS on a flat, non-conductive surface away from heat sources
Improper wiring can damage the BMS and connected batteries

Why Choose Enhanced 4S 40A BMS?

High 40A discharge capacity for demanding power tool applications
Active balancing extends battery pack lifespan
Auto recovery after fault conditions reduces maintenance
Low standby current preserves battery charge
Comprehensive protection ensures safe operation
Compact design fits standard battery pack configurations

√ Compatible with all 3.6V/3.7V Liion and LiPo cells

√ Supports 18650, 26650, and polymer battery formats

√ Direct replacement for standard battery management systems

√ Easy installation with clear wiring labels

√ Proven reliability for DIY and professional use

√ Excellent value for battery protection and management

Safety Precautions

Do not use with LiFePO4 batteries only Liion/LiPo (3.63.7V per cell)
Do not exceed 40A continuous discharge current
Ensure correct polarity and wiring order
Keep away from moisture and flammable materials
Use only with appropriate charger (16.8-18.1V for 4S)
Do not short circuit output terminals
Ensure adequate ventilation for heat dissipation
The BMS should be mounted in a protected area away from physical damage
For applications exceeding 40A continuous, consider a higher-current BMS model

What's Included

  1. 4S 40A Enhanced BMS Protection Board

The 4S 40A Enhanced BMS provides reliable battery protection and management for your 4series Liion battery packs. With comprehensive protection features, passive balancing, and auto recovery, it is the ideal solution for power tools, e-bikes, portable devices, and DIY battery projects.

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