Hi All,
My Turnigy 1000 maH Li-Po batteries wont work any more.
its not charging at all.
I had left it connected with the Rx over night.
I guess it is discharged completely, now when I connect it to the balance charger the led on charger wont lit. I left it for more than one hour and then tested again, but its not taking any charge.
Is it time to get a new battery or can something be done to fix this.
Please help.

try changing charger , do some low charging , like eco 6 etc , find near by hobbist

Try independently charging each cells through balance port using a Nokia phone charger. But you have to modify the connection between Nokia charger and balance port of lipo. Further you have to take care of the polarity. Once lipo builds some voltage it wil be recognised by the balance charger and will charge.

Balance port the negetive and positive end it's usually black and red and remaining in between will be many other colours.

@aafi-
yes that battery of yours is very much recoverable..dont worry..
sundaramvelar is absolutely right..the technique is called 1C charging..something like this had happened to me sometime back and i recovered my lipo following the advises of some seniors on this forum..to get a more detailed description follow the link below..

http://www.rcindia.org/batteries-and-chargers/lipo-problem-6703/msg77054/#msg77054

hope this solves your problem..

Thank you all,
Will try the 1c charging method.
hope it works..

Good luck Aafi. Please check the culprit cell that's voltage gone much below than other.
Just first charge that. and keep watch the temperature of the pack as well as any puffing/gassing.

Another thing, just after starting charging, smell if any CA like smell is present or not. If you got it,  any of the cell got damaged and capacity detorites. But if not then you are lucky.

I don't know why, but it happens even in Li-ion cell pack too.

 only the most experienced can say so

if still cannot charge, cut the plastic and look at the wires in case they were disconnected.  I learned not to keep my lipos in my pockets because the wires twist and turn and the solder connections break at the top of the battery!

Hi,
I cut the blue plastic and I see three wires
Red: +ve
Black: -ve
Blue: connects the 2 ends of the battery soldered together.
I have a Nokia charger 3.4v do I need to connect the end of the charger to the red and black on battery, and then charge for a few mins.
OR,
Do I need to connect the Nokia charger end to the +ve and blue wire.?
Sorry for the confusion, I am not sure how to xplain in a better way and please excuse me as I have very little knowledge on electronics.

First, safety is most important.  Don't let the wires touch each other or don't let metal to contact occur.  Get a magnifying glass and check the solder joints where the wires are connected to the battery.  Are the conections solid? 

The connections are solid and visible enough.

Hi,
Your LiPO and Li-ion cell is charged by the cell phone charger.
Both cell goes Deep discharge <3.2 Volt and over full charge >4.215 Volt.


Ref : http://www.fmadirect.com/lipo_handbook/FMA_Lipo_Handbook_Section2.htm
Any cell phone has the charger for single cell (Outut voltage = 4.5-5.2 volt with source impedence that limits the charging current.)

And as you say both battery are in series. So you need to charge both battery in series needs 8.5V+ DC Source; impossible for cell phone charger.

Now, measure the voltage of the cell and the voltage of the charger output (in energized condition).

You have to connect the charger +ve to battery +ve and -ve to battery -ve carefully as reverse polarity may blow the rectifier diode inside the cell phone charger.

At a time charge only ove cell and then the other cell inside the cell pack.

For safety, cover the battery terminals (After just checking the continuity with the charging terminals from solder) with cover and charge through charging terminals.
This is due to in case of short circuit, the max current will be limited upto blowing the charging terminal. And in case of battery connecting terminals, the current will be much higher and dangerous for the good cell.

Now, repeat for each cell till voltage increase upto 3.7+ volt and then connect with balance charger.

Hope, you have understand.

Thank you for the detail explanation, I will try and post the result.

Thank you all, My Li-Po is working now.

great!

kalyanprodhan
sir my lipo got over-discharged. i followed your post. i used samsung charger, 4.75V and 0.55A output current. how long do i have to charge mmy lipo
i am using a 2200 mah, 3S, 20C lipo from rcbazaar. please guide me. how will be able to know that my lipo is charged to more than 3V. please help

Just charge till each cell voltage goes above 2.7 volt so that the cell be recognized by balance charger.

but how am I going to know that its really charging?? because neither the charger nor the battery is getting heated up, as we find while charging li-ion batt

Then just charge through a torch lamp of 6 volt. Till cell volt remain zero, the lamp glow at 5 volt i. e. charger voltage and if the voltage starts to build up, the voltage across cell increase and the lamp voltage reduced and will dim.

Use this technique if you have no multimeter, as

Charger voltage = lamp voltage + cell voltage or
Lamp Voltage = Charger voltage - cell voltage as they are connected in series

And if the lamp is or no glow, cell internal impedance have increased and the cell have to give shock, to recover. In this case you need multimeter to check cell voltage and charging current.

Hope it will serve the purpose.