12volts 18650 li-ion battery pack charger

[jladre]

Can someone give me schematic for 12volts (3 x 18650) battery pack charger and 21 volts (5 x 18650) battery pack charger?
Please share it if you have.

[junkhunter]

i use a swallow charger will charge everything

[FatBob]

You can usually do it with one chip but prebuilt ones are cheap on the Hobby sites.

There are 2 ways to do it. One charges each cell individually called balance charging.
This is the best for a long life from the pack.

The other way is by the number of cells. Not as good as some will get out of sync and ruin the pack.

I disassemble laptop packs when they die and usually find 1 or 2 bad cells and lots of good ones.

Something like this will do a good job; http://www.hobbyking.com/hobbycity/s...idproduct=7028

[ppodg]

Budget solution for 1..3 cells, can be stacked for more:
http://www.hobbyking.com/hobbyking/s..._US_Plug_.html
On ebay they are cheaper.

[eclipse]

It's cheaper to buy them online than making one yourself.
Buy these battery chargers for less than 4$.
In fact I was busy soldering one to a new batt pack just few hours ago. The first appeared dead on arrival, no output voltage, nothing.
Thank god I had a spare one, which worked.

Did check - the ICs on this board cost more than if you buy the whole board.

[jladre]

Thank you guys for the suggestion!

[junkhunter]

pic of my swallow charger in my profile

[ercan]

http://www.ebay.com/itm/171393259180

[jladre]

http://www.ebay.com/itm/171393259180

[ppodg]

@ercan
That's only the mains adapter for a real chager.