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Do you need BMS for lithium ion batteries in parallel?

I have a device that runs on lithium-ion batteries. The device already has a charging circuit. The maximum load capacity is 300 mA, and the maximum charging current reaches 500 mA. To sum up, if there are 3 batteries in parallel (1 s3p), do I need to install a BMS or any additional protection circuit?

Battery Management System
September 28, 2023

Yes, installing BMS for lithium ion batteries is needed to protect your parallel circuit.
1. At a minimum, a combination of discharge cutoff and discharge current limitation shall be required.
2. Set the current limit by the BMS to slightly above your maximum 300 mA load, rather than the battery rating of a typical protection circuit.
3. In addition, when the battery is abnormal, BMS can help disconnect the circuit to protect equipment safety.

MORE: How many BMS should be installed for two separate lithium-ion battery packs connected in series?

Jessica Liu

Jessica Liu, an engineer at MOKOEnergy with 6 years of work experience, majored in automation at Hubei University of Technology. She has been involved in leading and monitoring comprehensive projects when worked for a top new energy company before. She is certified in PMP, IPD, IATF16949, and ACP. She excels in IoT devices, new energy MCU, VCU, solar inverter, and BMS.

Jessica Liu

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