3S 12V 8A / 12A BMS Protection Board for 18650 Lithium Battery

Is a 3S BMS protection board designed for packs of 3 lithium 18650 batteries connected in series.

In a 3S lithium battery pack, the nominal voltage is normally 11.1V, although it is often identified as a 12V battery pack. The full charge voltage is approximately 12.6V, and the board is listed for a charging voltage of 12.6V to 13V.

This board helps protect the battery pack against unsafe operating conditions, improving safety and battery life. It includes protection against overcharge, overdischarge, overcurrent and short circuit, with automatic recovery after short-circuit protection.

The listed maximum working current is 8A, with a maximum instantaneous current of 12A. For discharges above 3A, the batteries used must have a suitable discharge rate. The supplier indicates that the battery discharge rate should be higher than 3C for higher-current applications.

Wiring must strictly follow the battery pack points: B- / 0V, B1 / 3.7V, B2 / 7.4V and B+ / 11.1V. After the initial wiring, an initial charge may be required to activate the board output.

Main features

BMS protection board
Battery configuration: 3S
Battery type: lithium / 18650
Number of cells in series: 3 cells
Nominal pack voltage: 11.1V
Common designation: 12V
Charging voltage: 12.6V to 13V
Maximum working current: 8A
Maximum instantaneous current: 12A
Overcharge protection: yes
Overdischarge protection: yes
Overcurrent protection: yes
Short-circuit protection: yes, with self-recovery
Overcharge voltage: 4.25V ±0.05V per cell
Overdischarge voltage: 2.5V ±0.05V per cell
Quiescent current: less than 30µA
Approximate dimensions: 30 x 30 x 3mm
Connection points: B-, B1, B2 and B+
Main application: 3S lithium battery pack protection
Suitable for electronics projects and low/medium-current battery packs

Recommended applications

3S 18650 Li-ion battery packs
Portable 12V power supplies
Battery-powered LED lighting
Portable power modules
Lithium battery electronics projects
Low-power backup systems
Low-consumption electronic equipment
Small DIY projects using 3S batteries
Repair and assembly of compatible battery packs
Applications requiring 3S battery pack protection

Important note

Before use, always confirm the battery chemistry, nominal voltage, maximum charge voltage, discharge current, cell C-rate, wiring diagram, polarity and compatibility with the equipment.

For currents above 3A, use batteries with a suitable discharge rate. The supplier indicates that the discharge rate should be higher than 3C. For example, a 2000mAh battery rated at 3C can supply approximately 6A.

The cells used in the pack should have similar capacity, internal resistance and state of health. Do not mix good batteries with defective batteries or cells with very different voltages. If the cell voltages are not equal before series assembly, each group should be charged separately before use.

Incorrect wiring of B-, B1, B2 and B+ may damage the board, batteries or connected equipment. When working with lithium battery packs, always proceed carefully, avoid short circuits, use matched cells in good condition and ensure proper insulation.