HX-4S-A20 4S 20A BMS Protection Board for 14.8V 18650 Li-ion Battery Pack

HX-4S-A20 4S 20A BMS Protection Board for 14.8V 18650 Li-ion Battery Packs

The HX-4S-A20 4S BMS Protection Board is designed for compatible four-series lithium-ion battery packs, including suitable 18650 cell configurations. It provides battery-pack protection functions intended to help reduce the risk of overcharging, excessive discharge, overcurrent, and short-circuit conditions.

With a nominal pack voltage of 14.8V and a standard full-charge voltage of 16.8V, this board is intended for compatible 4S lithium-ion battery projects where suitable battery protection circuitry is required.

Key Features

• 4S battery configuration: For compatible four-series lithium-ion battery packs.

• 14.8V nominal pack voltage: Based on four series-connected 3.7V nominal Li-ion cells.

• Protection functions: Seller listings specify overcharge, over-discharge, overcurrent, and short-circuit protection.

• Compact PCB format: Commonly listed at approximately 35 × 35mm; confirm the dimensions of the supplied revision.

• Designed for battery-pack integration: Suitable for compatible DIY battery assemblies and electronics projects when the current and electrical requirements match the board.

Technical Specifications

• Model: HX-4S-A20

• Battery configuration: 4S (four cells/groups in series)

• Battery chemistry: Compatible lithium-ion cells

• Nominal battery-pack voltage: 14.8V

• Standard full-charge voltage: 16.8V for a conventional 4S Li-ion pack

• Advertised model rating: 20A

• Reported maximum working current: 10A in multiple seller listings

• Reported peak current: 20A

• Protection features: Overcharge, over-discharge, overcurrent and short-circuit protection, as listed by suppliers

• Reported board dimensions: Approximately 35 × 35 × 3mm; confirm against actual stock

Current-rating note: The 20A figure should not be assumed to be the continuous operating current. Multiple supplier listings describe 10A as the maximum working current and 20A as the peak current. Confirm the exact board revision, current limits, and operating conditions before designing a battery pack.

Installation and Compatibility

1. Use only compatible lithium-ion cells arranged in a four-series configuration.

2. Check that the cells are in suitable condition and have compatible voltage, capacity, and internal resistance.

3. Follow the connection labels and wiring diagram for the exact board supplied. Do not rely on an unverified generic wiring diagram.

4. Use a charger specifically suitable for a 4S lithium-ion pack with a 16.8V charging limit.

5. Confirm the board's continuous current rating, protection thresholds, and thermal requirements before connecting a load.

Important Safety Information

A BMS protection board is not a substitute for correct cell selection, appropriate charging, suitable wiring, insulation, and safe battery-pack construction. Do not assume that this board supports LiFePO₄ batteries, active cell balancing, or a continuous 20A load unless those features are confirmed for the exact model supplied.

Package contents: 1 × HX-4S-A20 BMS protection board, unless your supplier's package specification states otherwise.