Bad TP Li-Po cell , With Photo - RC Groups
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May 10, 2004, 08:59 PM
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tucson-01's Avatar

Bad TP Li-Po cell , With Photo

1 month old $45 TP2100 Lipo,

Decided to pull my lipos out of my aluminum case and store them in another container inside. Its been getting hot down here in AZ lately.

Upon inspection, I found one of my Li-Po’s to have a puffy cell.

This cell has neither been Dropped or Crashed in my plane.

I decided to try and salvage the good cell out of the pack.

HINT – if you store your cells in a metal container and open that container a leaking Li-Po has a Sweet Smell almost like cotton candy.

I had stored my cell overnight in a metal container with a Kevlar blanket.
I wasn’t taking any chances on burning my house down.

I took a photo of the corner of the bad cell. The side seam had smaller bubbles with
The same discoloring on the inside of the pack that could not be seen when it was wrapped.

It looks to me like damage was from the Heat Shrink process assembly? .
You can see for yourself there is no physical damage i.e. crushed corner.

I am not impressed with the construction of the TP battery , It looked like they soldered the pack with the tabs bent over next to the pack due to the coating discoloring from flux and heat.

Now do I use “Distilled Saltwater “ (distilled water is non-conductive)?
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May 10, 2004, 09:02 PM
Space Coast USA
hoppy's Avatar
Unbalance perhaps? What were the V's of the cells?
May 10, 2004, 09:06 PM
Registered User
tucson-01's Avatar
I havent taken voltage but the pack was at 8.05 before disassembly
May 10, 2004, 09:10 PM
You should return the damaged cell to TP. Based on your photo, theyll replace the entire pack for you:

Thunder Power Batteries
ATTN: Customer Service
4720 W. University Ave.
Las Vegas, NV 89103

Be sure to include your name, phone number and return address with the cell. You can also call them directly for more info:

(702) 228-8883
May 10, 2004, 09:11 PM
Registered User
tucson-01's Avatar
Bad cell has 4.02V

Good cell has 4.03V

Doesnt seem that unbalanced even damaged
May 10, 2004, 09:19 PM
Space Coast USA
hoppy's Avatar
So much for that theory ----

Looks like TP is taking care of you. Nice to hear about that kind of after the sale support.
May 10, 2004, 09:20 PM
Registered User
tucson-01's Avatar

Dont think sending back is an option now.

I don't really like the "Idea" of sending a potetially hazardous item in the mail
back to ThunderPower.

Funny thing is I picked up a Pack that had a dead cell only 4v on it and
got this one as a replacement pack.
May 11, 2004, 01:24 AM
Shortman's Avatar
Warp the bad cell up good and ship it Fedex and you should be okay. I did it before and Thunderpower took care of me.

May 11, 2004, 05:55 AM
Registered User
vintage1's Avatar
I think you mean wrap, don't you?

I am nervous of heatshrinking packs to be honest. It made sense with heavy metal cased cells where you really wanted to keep them snug. With LIPOS I am wrapping in insulating or parcel tape. I don't want to exert pressure on them or subject them to heat.

My 2c worth.
May 11, 2004, 09:22 AM
no place like cloudbase
freeflight's Avatar
That is interesting how the battery gave way in a corner. Not a part of a lipo cell I would think would give way. Of course any little hole/puncture damage is enough to kill the cell.

I do as Vintage and only use a more giving (read stretchs or breaks easily) material than shrink wrap. I have a few wrapped in electrical tape. Few in Blenderm 3M stuff. Not quite as neat a look but safer imho. Batts I buy ready made still have the shrink wrap on them. Perhaps falsely, I have more confidence in thier battery building abilities than my own.

May 23, 2004, 11:49 PM
Registered User
fleanme's Avatar

Similar problem in the same location

i sent in a pack a week or so ago to have it checked out. i used the a 3S1P 2100 pack about 2x and noticed a week after the use that the pack had slightly split and had opened in the corner of one of the cells.
i was worried too about sending the packs back but jason assured me that most any form of shipping would be safe. it arrived there so i assume things went smoothly. now i am waiting to hear back from them about why the pack failed.

tuscon-01, did you send your pack in?

May 24, 2004, 06:39 AM
Registered User
Originally Posted by fleanme
... I was worried too about sending the packs back but jason assured me that most any form of shipping would be safe. ...neal
Remember when manufacturer's reps were assuring us that imbalance would cause no problem with series-charged packs? Now as then, it's just a matter of time. But this time, a common carrier will be involved, not somebody's house.

Where is the AMA when they are really needed to preclude a real danger?
In bed with the manufacturers?

- RD
May 24, 2004, 01:28 PM
Registered User
Originally Posted by fleanme
i was worried too about sending the packs back but jason assured me that most any form of shipping would be safe.
Jason will not be popular with the commercial airline pilots on this forum who have expressed concern about the safety of shipping damaged Li-poly cells in the cargo compartment of a passenger jet. If damaged Li-polys are safe to ship by air, then they must also be safe to store under your bed while you're sleeping at night. Anyone doing that?

This is really a pretty simple matter, folks. If there's a technical reason why damaged Li-polys pose no risk in the cargo compartment of a passenger jet, then let's have an official representative of a Li-poly company go on record with that reason right here on this forum under his own name and the name of his company. For instance, if a really knowledgeable person like Thunder Power's Charlie Wang made a formal statement on the subject, it would go a long way toward settling this questionable safety issue.

I, for one, would just as soon put this issue behind us. But I'll be darned if I'm going to let loose of it as long as people's lives are potentially at risk and no credible representatative of the Li-poly cell industry is stepping forward to put our minds at ease.
May 24, 2004, 03:40 PM
Registered User
I would not ship the damaged cell by air or even ground for that matter, unless it was discharged and neutralized.

We are taking the risk that there will be some sort of transportation accident resulting in property damage or casualties.

You may be personally liable if you violated the carrier's shipping policies.

And then the shippers will refuse to carry any similar Li-Poly cargo, damaged or not, and no doubt Homeland Security will get into the act.

At that point most of our vendors will be out of business.

It really isn't responsible to suggest that anyone ship damaged cells.
May 24, 2004, 04:26 PM
Space Coast USA
hoppy's Avatar
We can take the lead by simply discharging cells prior to shipping. If a vendor doesn't approve of that procedure, ask for a procedure and a waiver of responsibility from them (in writing) for you to ship them in a charged condition.

Hopefully they will all agree that damaged packs be returned in a discharged condition. I can't recall of any discharged packs causing a problem - does anyone have knowledge of a discharged cell burning?
Last edited by hoppy; May 24, 2004 at 04:33 PM.

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