4S 21700 16.8V 15A Li-ion Battery Charging Protection Module BMS

4S 21700 16.8V 15A Li-ion Battery Charging Protection Module BMSThis advanced 4S 21700 16.8V 15A Li-ion Battery Charging Protection Module BMS is designed specifically to manage and protect a four-series lithium-ion battery pack, such as those built using 21700 cells. Furthermore, it monitors individual cell voltages and total pack current to prevent over-charge, over-discharge, and short-circuit conditions. Consequently, it ensures the longevity and safety of high-capacity portable power setups. Therefore, it is an essential component for custom cordless tool packs, portable LED lighting, and hobbyist electronics. However, users must strictly follow the correct wiring sequence for the balancing and power leads to avoid damaging the internal protection IC. Specifically, the board features an indented shape designed to fit directly alongside cylindrical battery cell configurations. Moreover, low-resistance MOSFETs and current-sense resistors allow the board to handle up to 15A of continuous discharge current. Ultimately, this BMS provides reliable protection for demanding multi-cell battery applications.

Key Features:

• Comprehensive Protection: Shields the battery pack against over-charge, over-discharge, over-current, and short circuits.
• Designed for 21700 Cells: Specialized PCB geometry allows for neat alignment and soldering directly onto 4S 21700 cell configurations.
• 15A Continuous Discharge: Equipped with heavy-duty switching MOSFETs and current-sensing resistors to support moderate load requirements.
• Balanced Cell Monitoring: Tracks voltage across all four series nodes to maintain uniform cell health and capacity.
• NTC Temperature Support: Includes designated pads for a thermistor to protect against thermal runaway during charging or discharging.

Technical Specifications:

• Configuration: 4S (4-Series) Lithium-ion Battery BMS
• Charging Voltage: 16.8V DC
• Continuous Discharge Current: 15A (with adequate cooling)
• Over-Charge Detection Voltage: ≈ 4.25V ± 0.05V per cell
• Over-Discharge Detection Voltage: ≈ 2.70V ± 0.1V per cell
• Operating Temperature Range: −20°C to +80°C

Mechanical Specifications:

• PCB Substrate: FR4 Green Solder Mask with reinforced copper traces
• Layout Design: Contour-cut edges tailored for 21700 cell pack alignment
• Connection Pads: Large, tinned surface pads for heavy-gauge nickel strip or wire soldering

Dimensions:

• Board Length: ≈ 42.0 mm
• Board Width: ≈ 42.0 mm
• Height: ≈ 4.0 mm

Pinout and Wiring:

• B+: Connect to the total positive terminal of the 4S battery pack (16.8V).
• B3: Connect to the node between the 3rd and 4th cells (12.6V).
• B2: Connect to the node between the 2nd and 3rd cells (8.4V).
• B1: Connect to the node between the 1st and 2nd cells (4.2V).
• B-: Connect to the total negative terminal of the 4S battery pack (0V).
• P+ / P−: Main charge and discharge power terminals (Positive and Negative output/input).
• NTC: Optional connection pads for an external temperature sensor resistor.

Datasheet Reference:

• Download Standard 4S Li-ion Protection Board Specifications

Commonly Used in:

• Cordless Power Tools: Rebuilding or constructing 16.8V battery packs for drills and drivers.
• Portable Lighting: Managing multi-cell power sources for high-output LED searchlights.
• DIY Power Banks: Creating custom 16.8V rechargeable energy storage systems.

Applications:

• Battery Pack Rebuilding: Replacing failed protection circuits in commercial tool batteries.
• Custom Electronics: Providing safe power management for portable field instruments.
• Consequently, it safeguards high-drain equipment from catastrophic cell failure under heavy loads.

Equivalent Models:

• 4S 18650 20A BMS Module: A similar multi-cell protection board with alternative current ratings.
• 4S 30A Li-ion BMS Board: A higher-current version designed for heavier power tool demands.

Package Includes:

• 1 x 4S 21700 16.8V 15A Li-ion Battery Charging Protection Module BMS