Author Topic: Charging 18650 LiPo cells via BMS, using a non-constatant current PS  (Read 1342 times)

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Offline bill6560Topic starter

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Hello all,

I'm in the process of building a 4S/14P power pack (for ham radio use**) using 18650 LiPo 2600mAh (2.6Ah) cells, for 16.8V (4.2Vx4) at 36Ah total. With the battery pack, I'm using a smart JK-BMS 4S BMS for charge/discharge control. I don't have a constant current power supply for charging, but what I intend to use is a regulated 18 Volt (±10%), 180W, 10 Amp switching PS to charge the pack, with the PS's voltage output set to 16.8 Volts. The PS (https://www.amazon.com/dp/B07STRPMFY) specs state that load current should limited to 80% of rated current, or about 8 Amps for safe use.

My question is, using this non-constant current PS, the maximum charge current will be limited to PS's 8-10 Amps. If my math is correct, for 14P cells, at 10A that's about 714mA (0.28C), or at 8A that's about 570mA (0.22C) charge current per cell. The PS does have Over Current, Over Voltage, and Short Circuit protection.

Another unknown is whether the BMS will control the charge current to limit it to 8A, however the JK-BMS app does have a setting for "Max Charge Curr (A)".

Will this work and be safe for the cells?

Thanks,
Bill

** P.S. To limit the initial voltage of the pack's 16.8V, I'm inserting a 60A full bridge rectifier in series to limit the voltage to a safe 15.4V for my ham gear. Once the pack settles down to it's nominal 3.6V/cell voltage (~14.4V at 4S), I'll switch out the bridge rectifier.
 

Offline Simon

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Re: Charging 18650 LiPo cells via BMS, using a non-constatant current PS
« Reply #1 on: June 12, 2024, 08:44:45 am »
Please don't double post. It will make you very unpopular as people feel you are wasting their time.

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