hi guys

i have found this charger to be cost effective,simple and popular charger design among R/C people. I was looking to build one to charge my Lithium-Polymer packs that i got from aircraft-world which I'm gonna use in my Scratch build 2ch plane.
Although the heading says Lithium-Ion this has been well used on Lithium-Polymer cells! the cost of the charger with a good adapter will cost some thing like 250 rupees using which one can charge 3 cell n up to 985mamps.

i have included components list (if any mistakes please point then out) for more details please visit this link and yes i will put it in a nice box 

http://shdesigns.org/lionchg.html

sahil

please Note: use only 1% tolerance resistors (accurate current values and the priced i have given are for 1% type) and i have not used a 10turn preset but one should have then (its a must to get correct voltage cut off)  

sahil

Cool ! 

I guess it only charges, and does not balance the individual cell voltages ? 

Not meaning to discourage you in any way, but I have in the past ordered $10 chargers for 2s and 3s lipos with balancing capability from HongKong and Taiwan.  They arrived in India without any customs duty/issues, so that would be a better option.  Balancing is so crucial to safe and prolonged use of Lipos.

yes i completely agree with you but my cell don't come with balance connectors and this charger was built with the intention of using it for 1-2c packs with capacity below 500mamp and charging at 3/4th capacity of a given cell!(I'm my case).Picture of the DC adapter and setup!

sahil

please read this article on Lithium-Ion battery precautions by Panasonic, the Lithium-Ion charger that i build uses the standards mentioned in the above article.

http://www.panasonic.com/industrial/battery/oem/images/pdf/panasonic_liion_precautions.pdf

sahil

Nice work Sahilkit,
i have also made the same charger but done some little modification as suggested by one the member  in wattflyer. go through this link below.

http://www.wattflyer.com/forums/showthread.php?t=20575

this charger is working fantastic. also, i am in process of making  the charger using old Laptop battery circuit PCB inside the battery pack itself. once i am through with the construction, will post the details here. i am sure people will find that use full.

hi sandeep

thanks

Quotealso, i am in process of making  the charger using old Laptop battery circuit PCB inside the battery pack itself

can you give more details like how many cells the laptop battery has and how many are you planing to use.If the number of cells in the laptop battery = number of cells in one's pack then should not have problem ! the reason i have asked this is,the cut off voltage on the laptop battery PCB is fixed to a X number of cells now if one plans to use less cell-they will overcharge and you know what happens !

but if you have modified the circuit to accommodate various pack sized n capacity etc,then i guess it should be okay.

sahil

to anwar

your concern on balance charging the cells has been met, thanks to sandeep (see the link he posted or below) this is actually a Lithium-Ion Charger II configured to a fixed current and to single cell (4.2 volts) a number of these are kept in series and output given to JST type Balance connector 

http://www.wattflyer.com/forums/showthread.php?t=20575

sahil

Sahil,
The no. of cell in the pack is 6 each of 2200 mah each , 2 cells in parallel means 3 sets.
the current version of 2 and 3 cell which i am using is working fine but i have noticed that the pack is not able to give sufficient power to motor and i guess is due to low discharge rate of li-ion cells. i have no idea of discharge rate of cells, but i am sure with the new charge design using the battery pack PCB i may find the solution. till time wait for completion of the charger.

Sahil,
Make two more sets of charger what u have made and put it exactly in the manner shown in wattflyer model and yours also can be a balanced one. try to make next two in a single PCB.
Sandeep

hi sandeep

will do that but in time 

sahil