How can i charge 6 pieces of 18650 lithium ion cells together using a laptop power supply with auto cut charging when fully charged ?

LGDS318650 H3314903243 KK264D9S3

This is printed on each cell. My cells are in 3S2P order and my power supply is 19v and 3.9 amp. Is there any possible way of charging them.

  • 1
    \$\begingroup\$ Insufficient data. Provide schematics please. \$\endgroup\$
    – Dampmaskin
    Jul 2, 2016 at 12:04
  • \$\begingroup\$ Please provide more data \$\endgroup\$ Jul 2, 2016 at 12:53
  • \$\begingroup\$ Dear sir, data provided. \$\endgroup\$
    – changer
    Jul 2, 2016 at 19:11
  • \$\begingroup\$ No. Your laptop supply does not have any constant current mode what so ever. Get yourself a Li-ion charger. \$\endgroup\$
    – winny
    Jul 3, 2016 at 7:34

1 Answer 1


What charger voltage?
Do you really mean laptop power supply?
ie the often 19v rated supplies are NOT a charger by themselves - the charger proper is inside the laptop.

6S = 6 cells in series. 3S = 3 cells in series. 2P = 2 strings in parallel.
3S2P = 2 strings in parallel. Each string = 3S.

Minimum final charge voltage for 6s LiIon = 4.2 x 6 = 25.2V so average 19V psu will not work.

3S2P = 3 x 4.2 = 12.6V so you need a buck converter or similar from 19V.
Even a psu of the "correct" final voltage is just waiting to destroy cells if used by itself.

What you need is a dedicated LiIon charger. You can design and build these from parts but in most cases buying a 3S2P commercial charger is easiest and lowest cost. Max current for 18650 is USUALLY in the 1A to 3A range. You need a datasheet for the cells to see what Imax is safe. While SOME cells allow C/1 rate charging and have 3000 mAh capacity so 3A is OK, others allow only C/2 charging and some MAY have capacities closer to 2000 mAh so only 1A max may be allowed. Anything much over 3000 mAh is a fake.
Even the highly reputable Panasonic only allow C/2 max for some of their LiIon cells.


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