Reubster24

iTrader: (37)

Hey everyone I hope this will be helpful to someone.
I got a 3s 5000mah tenergy lipo in a sale and one of the cells had noticeable damage to it. I have 2 of these 3s batteries and I was going to run them in my brushless revo. I tested the voltage on the balance plug and found 2 cells were fully charged at 4 volts and 1 had only .4 volts. I decided rather then throw away the whole pack I would take the pack apart and see if I could remove the bad cell and make a 2s 5000mah battery.

Here is what the pack looked like once I got the shrink off it. Be very careful not to puncture the actual lipo cells when getting the shrink off.


Here is the tabs that connect the cells together. Sorry for the bad picture.


I started by removing the positive lead and the balancer wire coming from the plug going to the positive side of the first cell in the 3 cell series. Be very careful not to get the cell to hot. If it isn't coming lose and the cell is getting hot. STOP, let it cool then try it again. The balancer wire in my case isn't needed any more since I'm making the pack a 2s pack now. Just remove it from the balancer plug and throw away.


Next I had to remove the negative side of the 1st cell from the positive side of the 2nd cell in the series. I oppted to just cut the tab because there was a lot of solder and I didn't want to heat the good cell up to much trying to get the tabs unsoldered.


Once the bad cell was out I tested the voltage and it was definitely bad


Next I just had to solder the main power lead to the positive tab that I cut from the bad cell. Be very careful not to get the cell to hot.


I wrapped the new pack in electrical tape for now cause I don't have and plastic shrink. Tested the voltage and all is good.


Here is the finished product until I get some plastic shrink. I wrote on the pack what it now was for future reference.


A lot of people are scared to take apart a lipo. The fact of the matter is lipos are dangerous when they are being over charged, being over discharged, being overheated or being charged(when they are damaged). Possibly dangerous if the actual cell is punctured while working on it. Lipos do not just spontaneously combust or catch fire. The only issues you run into in working on a lipo pack is the possibility of puncturing a cell. Which is pretty easy to avoid. Or overheating a cell with your soldering iron. If you know what your doing this should be easy to avoid as well.

For anyone that wants to try this. You will need a good soldering iron and know how to solder. DO SO AT YOUR OWN RISK. I'M NOT RESPONSIBLE FOR YOUR ACTIONS!!!

If you are uncomfortable doing it I would be willing to do it at your expense. Just shoot me a PM with what you have and I will let you know what I can do.

If you would rather just throw away good cells shoot me a PM and I will pay for the shipping and get the pack from you.

Hope this write up will be helpful to everyone.
If anyone has any questions just comment here or send me a PM. I will be glad to help out.

trickedout

iTrader: (31)

The whole WORRY about lipos always makes me laugh...Its not a damn A-Bomb waiting to go off.. Look at the factories this are made in, they aren't wearing bomb proof vests while assembling these. Good right up!

Reubster24

iTrader: (37)

Well said. I'm not scared of lipos one bit. Unless they are hooked to a charger or toward the end of a hard run. That's when crap hits the fan!!! Not when your working on it and the pack is just sitting there. Once the cell is puffed or damaged it still isn't a ticking time bomb unless you try to charge it. If you just ran it hard and it puffed I would let it sit for a minute before let your kids play with it.