lithium polymer charger

li-polymer 3.6v charging schematic

i need 2 cell lithium polymer charger schematics with voltage level detection.i mean auto cutoff.please guide me

Li Polymer cells needs special charging profiles for proper charging of the cells.
Then charging a twin cell needs even more precise method due to cell imbalance.
Special charger IC are available for such purposes. Attached are some IC I used before.

lithium multi cell charging ic

Anyone know how to make 11.1V 3cells lithium polymer charger???

maxim lipo charger

i m building 2 cell lipo charger with lm317 for current control.and i will sense voltage level with op amp.show u if success

2 cell lipo charger schematic

I think that lithium chargers have to be carefully designed as if over charging occurs the battery can explode etc
this is why 90 % of charge will be achieved in the 1 st hour then full charge is achieved in another 1 hour. At least Ni MH and Ni Cad vent and loose capacity if abused !

schematic 3 cell balanced lipo charger

lithiums have a nominal value of 3.6V/cell..... they should not be discharged bellow 3V.... charging them should be 4.2V/cell.....

lithium polymer chargers

mark 123 i have question about lipo that after charging lipo cell upto 4.2V if i continue charging and voltage of cell will increase more than 4.3V.then what happens.will lipo get worm? or explode witout worming?
coz i want to implement over temprature sensing in my charger.
thanx

11.1v lithium charger maxim

Look at that:
**broken link removed**

11.1v charger schematic

i have similar problem- I am trying to use thre cells salvaged from old fones. Two of the cels match and anorther which I have chosen for my 3 cell pack does not. I want to wire the three packs up after cutting out the Vreg and whatever else circuits which are currently on the cells themselves. I have been checing out various charging IC's- TI has some promising ones, Maxim too. Finding one whch is capable of multi-cell chraging is not a huge deal but fining a package which can be easily worked with can be harder. TI does offer some of their devices in CIP package but Maxim not so much. I believe that the BQ2000 looks promising (TI).

Anyways, I am wondering what sorts of charging and matching issues I have to look forward to with designing this interface/charging circuit? Will I be able to use the three cells even though at least one isn't mathing? are there other things which I have to keep in mind>? Haven't yet worked with these types of cells yet so am in newbie territory!

Thanks in advance for any help with these issues, regards, jd

11.1v polymer charger schematic

Every standard multi-cell battery apart from multi-cell protection IC should include so called Gas Gauge IC that monitors each cell voltage and care about their balance. Except the cell voltages it nonitors current and temperature also. In case if one of the cell is unbalanced the part of charge charge current bypasses the cell that overcharged in comparision with the rest of batteries.

11.1v lipo charger +schematic

I think you can modify the circuit here **broken link removed**

or check out this website http://www.rcgroups.com/forums/showthread.php?t=130567