BMS 3S 12V 40A

Reliable 3S 12V 40A BMS (Battery Management System) for Li-ion / Li-poly battery packs. The system balances cell voltages and provides overcharge and over-discharge protection, thus extending battery life and ensuring safe operation.

Customization

• 12 Class V (3S) e-mobility, DIY and power projects
• LED lighting, UPS, audio, modelling, small e-devices

Main functions

• Balancing (3S): reduces cell imbalance during charging
• Protections: overload, over-discharge, short-circuit and over-current
• Continuous discharge up to 40 A – reliable for 12 V systems

Specifications

• Number of cells: 3S (3 cells in series)
• Chemistry: Li-ion / LiPo
• Nominal voltage: 11.1 V (~12.6 V when fully charged)
• Max. Continuous discharge: 40 A
• Balancing: passive (3 channels)
• Temperature protection: supported if the version includes a sensor

Installation notes

• Follow the terminal diagram: B-, B1, B2, B3(=B+), P-/P+, C-/C+ (if separated)
• Perform the first start-up without load, check cell voltages
• Use CC/CV 12.6 V charger (3S Li-ion)
• Fuse on battery line recommended; ensure ventilation

FAQ

Is it suitable for 18650 and 21700 cells?
Yes, if the pack is 3S Li-ion/LiPo and the current and cooling requirements are met.

Can I charge via the BMS?
Yes, with a 12.6 V CC/CV charger (3S).

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