Converting 3S to 2S

[chiadennis]

Check with you guys if yu have the wiring for converting TP extreme V2 from 3S to 2S? I found that only 1 cell is bloated and I want to cut open to salvage the other 2 cells.
Thanks

[tampines flyer]

well me also wanna change from 3s to 2s cause i bloated. so any bro know how to do it pls advice tks

[Adrianli]

I have changed a PolyRC from 4S1P to 3S1P to 2S1P. Its a 3700mah pack.

[tampines flyer]

ok u see let say the main wire red to 1st cell + - and + -2nd cell rite .
my ? is how to join bal. wire red to where and black to where .

[DL8698]

I also have a 3S1P pack with the middle cell dead. Tried to separate the 3 cells but they are so tightly stuck together that I'm having difficulty pulling them apart. Dare not pull too hard as I might bend the good cells which I guess will kill them.

The middle cell has already spilt some of the electrolyte out, voltage is almost zero. If I were to soak the middle cell in salt water for 2 days, would it be safe to cut open? I'm the type who likes to open things up just to see what it looks like inside, so is it ok to cut the dead cell open, after soaking and confirming that the cell has no more voltage?

Hope Dennis doesn't mind I use this thread to ask this question, as have been wondering for a long time.

[DL8698]

I also have a 3S1P pack with the middle cell dead. Tried to separate the 3 cells but they are so tightly stuck together that I'm having difficulty pulling them apart. Dare not pull too hard as I might bend the good cells which I guess will kill them.

Sorry, meant to ask also, how do you separate the cells when they so tightly stuck together?

[VinCopter]

This is what I did to kill the cell/pack. Drain out all the juice in the cell/pack by connecting it to a load (motor, light bulb, etc). Once the voltage has drop to zero; motor not running or no light already. And leaving the load connected, solder a short length of wire across the two poles ( + / - ). This should permanently short the cell/pack, and kill it. Later cut a few slots on the cell/pack and soak it in salt water for a day before disposing it down the chutes.

Any Bro like to comment on this method? Good, bad, anything?

[VinCopter]

It is very difficult to separate the cells from a pack. You may want to try the above method after cutting slots to release any pressure in the dead cell. Than split the dead cell and take out it contents, leaving the cell skin still stuck to the good cells. This way, you can avoid the need to pull/separate any cells.

[Lplate]

Are the cells held together by glue of some sort?
Guess if you can figure out the solvent, then maybe can take out.

[yacsf]

I have done it before on other type of lipo battery. Yes you must be very careful not to short those working batteries, cos it can cause sparks and worse explosion.

Unwrapped the tape and then measure which one is the faulty battery. Remove it carefully by cutting the terminals. Then slowly de-solder out the terminals.

Got to remove the 4 wires of 3S connector out. Remember and do marking first before removing them.

After remove the faulty battery terminals from the PCB. Use a wire to short the 2 terminals. With a multimeter, measure the 2 working batteries, it should read 7.4V.

Change to 2S connectors and solder them back. Measure the 3 wires. It should read 3.7V and 7.4V.

Wrapped it with insulation tape.

[DL8698]

It is very difficult to separate the cells from a pack. You may want to try the above method after cutting slots to release any pressure in the dead cell. Than split the dead cell and take out it contents, leaving the cell skin still stuck to the good cells. This way, you can avoid the need to pull/separate any cells.

From what you say, it appears after doing the salt water soaking and dropping to zero volts, whatever is in the dead cell does not pose any "health" danger, ie, none of the chemicals inside is poisonous or corrosive and should be safe to handle. In fact, I too was thinking probably have to tear the dead cell apart to separate the good cells but hesitated as not sure if the "stuff" inside the dead cell pose any danger. So, I guess it's ok to chop up the dead cell in order to retrieve the good cells.

Thanks for your advice.

[DL8698]

Are the cells held together by glue of some sort?
Guess if you can figure out the solvent, then maybe can take out.

Not sure if it's glue or double sided tape but it sure sticks like crazy. Dare not pull the cells apart any more to see what's the sticky stuff cos the good cell was starting to bend.

[Frank]

Check with you guys if yu have the wiring for converting TP extreme V2 from 3S to 2S? I found that only 1 cell is bloated and I want to cut open to salvage the other 2 cells.
Thanks

If you are talking about wiring balancer taps, black + white is cell no.1, white + blue is cell no.2

[thong]

Battery connection

Maybe these might help.Thanks