I am designing battery charger and I want to know how to calculate max charging current for a lithium-ion battery pack. I am using Texas Instrument Chip bq24616 and their evaluation board.

Assumption: Battery pack has- 5 in parallel and 4 in series of 18650 batteries include onboard BMS.

Base on the datasheet of the battery:

Each cell is 3.7V 2500mA

Standard Charge current 500mA

Battery pack = 14.8v 20AH

Is that mean max charging current is 5 x500mA = 2.5A

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2 Answers 2


Yes, according to KCL the charge current splits up into five equal partial currents when five cells are nearly identical and connected in a parallel manner. Therefore you should always create a battery pack consisting out of cells from the same batch.

  • \$\begingroup\$ Yes, all are same battery. So even if you do fast charge max is #parrallel cells x recommended charge per cell \$\endgroup\$
    – Shahreza
    Commented Jun 26, 2020 at 19:23
  • \$\begingroup\$ There are different fast charge algorithms. In none of the possible charging modes you should exceed the maximum charge current stated in the cell data sheet. \$\endgroup\$
    – Amigo54
    Commented Jun 26, 2020 at 19:33

Currently, you just mentioned only the standard or recommended charging current of the cell (in your case 0.2c), if you need to calculate max charging Current then you need to know the max charging current of the cells in parallel. then multiplication of the max charging current of each cell with the number of parallels will give the max charging current of the battery pack. Addition point to give attention to is that most Battery Management System (BMS) has "charge overcurrent protection" with a tolerance. so your max charging current is as well limited by the lower limit of charge overcurrent protection of your BMS.


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