I have a 4S2P Lithium-ion battery for my quadcopter. I'm charging it with the Imax B6. I would like to ask what would be the suggested charging current for the battery pack with the 4S2P setup? Thanks!


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  • \$\begingroup\$ Some value in the range specified on the battery's datasheet, that is also supported by the charger. Within that range, make your choice based on how fast you want to charge, and how long you want the batteries to last (slower charging increases their life). Since you haven't linked any relevant data, the rest is up to you. \$\endgroup\$ – Brian Drummond Sep 9 '17 at 12:52
  • \$\begingroup\$ Each cell have 2600mah capacity and the charger has maximum 5A of charging. \$\endgroup\$ – Dave Benemerito Sep 9 '17 at 12:57
  • \$\begingroup\$ That doesn't tell you the acceptable charge rates for the cell. You need the supplier's datasheet for that. If they don't have one, the cells are probably junk anyway. \$\endgroup\$ – Brian Drummond Sep 9 '17 at 13:03
  • 1
    \$\begingroup\$ "Each cell have 2600mah capacity" - but the battery configuration is 2P, so does that mean its capacity is 5200mAh? And is it really Li-ion (cylindrical cells in metal cases), or actually Lithium-Polymer (rectangular battery with plastic wrapping)? If Lipoly, what is its 'C' rating? \$\endgroup\$ – Bruce Abbott Sep 9 '17 at 13:15
  • \$\begingroup\$ The C rate is the multiplier for 1 hr charge/discharge rate of the battery Ah capacity. so a charge current rises with lower battery ESR and the C ratings then rise accordingly. \$\endgroup\$ – Sunnyskyguy EE75 Jan 15 at 0:17

The Imax B6 has maximum charging power of 50W. A 4S Li-ion/Lipoly battery charges to 16.8V (4.2V/cell), so the maximum current the charger can do is 50W/16.8V = 3A.

A battery rated to handle the current drawn by a quadcopter of a size suitable to carry it will almost certainly be rated for at least a 1C charge rate. Maximum charge rate = charge 'C' rating x battery capacity in Ah. At 1C charge current = battery capacity.

So the only question remaining is - what is the capacity of your battery? If it is greater than 3000mAh then set the charger to 3A. If it is less than 3000mAh then set the charger to the battery's capacity eg. 2.6A for a 2600mAh battery.

  • \$\begingroup\$ Thanks! I'm really not that knowledgeable on battery charging, ratings and calculations. Looking forward to apply these in future projects. :) \$\endgroup\$ – Dave Benemerito Sep 9 '17 at 13:36
  • \$\begingroup\$ Last question @Bruce Abbott, for example my battery is configured in 3s3p, 50W/12.6 = 4A. Will I charge the pack with 4A of current? \$\endgroup\$ – Dave Benemerito Sep 11 '17 at 10:35
  • \$\begingroup\$ Not 3s3p sorry.. Imean 3s2p✌ \$\endgroup\$ – Dave Benemerito Sep 11 '17 at 10:40
  • \$\begingroup\$ If the total battery capacity is 4000mA or more, yes. \$\endgroup\$ – Bruce Abbott Sep 11 '17 at 15:22

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