Have I ruined my LiPo?

Started by SK1701, January 26, 2015, 06:56:02 PM

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SK1701

I have a Wild Scorpion 3500 mAh battery. Last week, my quad decided to spin up its motors while I was trying to plug in the lights and it flipped (I think the Tx got turned off as the switch was not properly turned on). Luckily, I wasn't hurt but the balance lead of my LiPo got damaged.  While trying to position the connectors for charging I accidentally shorted a cell for a very short time (saw a spark but there is no visible damage) I was still able to use the LiPo but today, while flying, a prop nicked the balance lead and now it is in bad shape. I had another cell short and the LiPo was warm and slightly puffed after use. I got the stupid idea of poking the outer wrapping of the LiPo and saw a spark (along with the sickly sweet smell of the electrolyte). It is no longer puffed and I covered the hole (no more smell). The battery is cool to the touch and I have put heat shrink on the cell wires. The cell voltages are: 3.68, 3.69, and 3.71. I want to know if this LiPo is still useable. I would prefer not to have to throw it as it cost me 2 grand. I would like advice on what to do now. I am guessing I need to replace the jst-xh connector. Where can I get one and how do I go about it?
I understand that what I did (poking a hole) was dumb as well as dangerous but the battery is now cool and there is no smell. I am keeping it in a LiPo safe bag on a granite floor and watching it. From my reading, I have been very lucky as the LiPo could have caught fire. I have attached some pics.

Himadri Roy

I would recommend not using it...You could try to repair the damaged cell but it could prove dangerous...And as you have poked the cell too the Lithium inside the battery may spontaneously react(with moisture) causing explosion. Better to throw the battery than to loose the house or model to lipo fire! :thumbsup: :thumbsup: :hatsoff: :hatsoff: :hatsoff:
For once you have tasted flight you will walk the earth with eyes skywards for there you have been and there you will long to return
- Leonardo Da Vinci

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SideWinder

Wow, I believe you have probably read somewhere that pricking puffed lipo and resealing it does the job. Bad idea tho. You also had a spark when you pricked it, which could mean trouble as you may have shorted the cell internally.

Try to charge the battery(safely, somewhere outside, away from anything inflammable), if it does so safely use it on ground for testing or powering something carefully. I have a couple of puffed batteries which I use for powering parts of ground station or for bench testing motor/props or setting up copters or anything else.

You do have the option to remove the damaged cell and use it as 2S if rest of the cells never shorted or damaged but that needs some homework on your part and is messy.

Anyhow dont fly anything on it, take a loss,save money and get a new battery. Better than losing the rest of the stuff.


sooraj.palakkad

I have JST XH connector (4 wire for 3S)  , PM your address, I will ship it :)
RC Hobbyist and an Aerial Cinematographer..

SK1701

Thanks for the replies.
@Himadri Sir, I read that there is no elemental Lithium in a LiPo but there is definitely a fire hazard. I will go for a new LiPo.
@Sidewinder Sir, none of the cells seem damaged plus I don't have any use for a 2S LiPo so that option is out. I will try a charge this weekend at a low current (1 amp or so) and share the results. I don't want to risk my quad but do you think I should try maybe a short hover to see if it is OK. Which brand of LiPo would you suggest? I liked the Wild Scorpion but was not able to get many cycles out of it thanks to this problem. I had a bad experience with WolfPack (partially my fault but I have read similar complaints).
@Thanks for the offer Sooraj, I will pay postage. Where did you get the connector?
How do I go about putting a new jst-xh connector on my LiPo (still not sure if I should do it).

sooraj.palakkad

SK, It's completely free, If you insist on paying, you won't get it for sure :)

you can just solder the connector terminals to existing balance leads, and Heatshrink it. Or for a tidy look you can open up battery and solder the leads directly (After removing old leads.) - But I won't do that much for a pierced and once shorted weak LiPo pack !
RC Hobbyist and an Aerial Cinematographer..

SideWinder

So are you going to short hover all the time?
And even if it hovers, would it guarantee that it wont fail in normal flight?
What if it leaks in flight?

Please dont be naive just because you would end up spending some more money. Im not even sure whether it will charge, and that too without any incidents. So whatever you do is your judgement call. I would say that battery in its 3S form is not recommended for flight.

And as for batteries, all the batteries that I took care off are still there with me after 2 years of use and I have another set of batteries which were abused,crashed,over drawn,dented,scratched,shorted & punctured with nearly 90% of it being my mistake. I have used wolfpack,qk lipo,turnigy,multistar,wild scorpion and a couple of unbranded lipos.

I have used 1500mah 3s wild scorpion which underwent roughly 45 cycles in a month on a mini quad. It just used to warm up a lil and never puffed . But lost it because I left the lipo alarm attached to it overnight and all except one cell were at 0V. It refused to comeback to life. I lost a wolfpack and turnigy because they were stored above storage voltage for a long time. They are all now puffed. So my point is lipos that are attended and cared properly would last long.

Rcjabalpur

Take a bucket of salt water and throw the lipo in it , or you can put it against a load and discharge it . Do not use damaged lipo , in the end you will pay more than what the lipo was worth .
Hobbico next star | sky surfer V2 | .46 High wing trainer | O.S .46 Ax | O.S .46 La | O.S 55 AX | super tigre .10 motor | Spektrum DX5e | FUTABA 10J | Hitec X4 Eighty | Phoenix Scanner | Multiplex Twinstar ii

Acquiring soon |  no plans as of yet  |

The ultimate responsibility of the pilot is to fulfill the dreams of the countless millions of earthbound ancestors who could only stare skyward and wish.

SK1701

@Sidewinder sir, thanks a lot. This LiPo will be kept in a metal box and used for some testing or minor applications (If it charges). I won't risk my quad for this.
@rajjaiswal92 Sir, I have read that the salt water method is not advised as it does not guarantee that the LiPo is discharged (it corrodes the connectors). An electrical load is much better. Anyway, I don't plan to dispose of it as of now.

Himadri Roy

Sk please don't call me sir i am just 2 years elder to you and by lithium ion i meant the in the solid electrolyte in lipos the li ions are present and li ions are reactive. What is the reason of the lipo fire shown on youtube when someone stabs it with a screw driver? the highly reactive ions react with H20(moisture) causing violent and exothermic reactions :hatsoff: :hatsoff: :)
For once you have tasted flight you will walk the earth with eyes skywards for there you have been and there you will long to return
- Leonardo Da Vinci

https://www.youtube.com/himadrifpv