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Old Mar 30, 2013, 06:58 PM
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Joined Mar 2013
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Question
LiPo battery discharge lead came off

Hey guys,

So I crashed my multirotor the other day, and apparently the battery wasn't secure enough because it had fallen off and the positive lead was pulled right out. It's a 4S 4000mah. I've cut open the shrink wrap on the end, and I can see where it was connected but I'm not entirely sure if/how I can put it back on. Everything else appears to be fine. It doesn't look soldered, and I can't imagine it would be safe to put that much heat on a LiPo right?


Thankfully the multirotor is totally fine other than that, and I have another battery. So not a big deal but I'd really like to fix it instead of buying another one.
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Old Mar 30, 2013, 08:08 PM
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ggcrandall1's Avatar
USA, GA, Marietta
Joined Aug 2005
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It looks like the tab broke off of the cell. It might be possible to repair if you have good soldering skills or if you have access to someone who does. If not then the battery is a write off.

Glen
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Old Mar 30, 2013, 09:43 PM
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rampman's Avatar
USA, AZ, Gilbert
Joined Jan 2006
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Probably a gonner. By the time you figure out you can't get the solder to stick to the remaining tab you will have put so much heat into the tab that the seal will be voilated.

Rick
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Old Mar 30, 2013, 10:12 PM
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Well, good thing I haven't tried it yet. Is there anything I can do? I'd really prefer not to buy a new battery.
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Old Mar 30, 2013, 11:19 PM
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I managed to fix it! I figured it was worth a try. I was able to sort of crimp the the two pieces together to get good contact, and then I soldered it very carefully.The solder bond isn't great but it works and I put a ton of strong tape over it. I'll be extra careful with it until I can get a new one. Thanks for the info though guys.
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Old Jul 21, 2014, 11:23 AM
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bosco99's Avatar
United States, CA, San Clemente
Joined Apr 2014
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Thanks so much for this posting. First had the lead come off then the lead tape and I had no idea what to do as batteries are not inexpensive. Got it on and battery checker says all okay. thanks again for the added confidence to pursue this repair
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Old Jul 21, 2014, 12:29 PM
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United States, WA, Woodinville
Joined May 2014
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Quote:
Originally Posted by TigerFire View Post
I managed to fix it! I figured it was worth a try. I was able to sort of crimp the the two pieces together to get good contact, and then I soldered it very carefully.The solder bond isn't great but it works and I put a ton of strong tape over it. I'll be extra careful with it until I can get a new one. Thanks for the info though guys.
They are usually soldered to the leads, and tabs are spot welded to other tabs.

Put some epoxy over the joint, that will keep it together.
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Old Jul 21, 2014, 03:09 PM
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Haralson County GA. USA
Joined Oct 2004
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If the repaired battery causes a crash it could cost a lot more to repaire than another battery would have.

I use to read post of people useing epoxy,shoe goop ,JB Weld etc to repaire holes / cuts in LiPolys and some clamping bent ones in a vice to stregthened them out. All seem very risky to me and a decent 3S 1500 does not cost $40 or more like they did 10 years ago.

FYI I have the special flux and solder to solder to LiPoly tabs which do not have the nickle taps spot welded to them burt these days LiPolys are not worth the effort to repaire unless they are very expensive ones and you have enough bad (damaged) ones on hand to salvage cells from.
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Old Jul 21, 2014, 05:41 PM
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I'd be concerned that the repaired connection would not be capable of withstanding 10C or 20C current.
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Old Jul 21, 2014, 11:12 PM
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Originally Posted by chuck75 View Post
I'd be concerned that the repaired connection would not be capable of withstanding 10C or 20C current.
Try it out on the ground and find out. I see no reason why it wouldn't though, people solder connectors on batteries all the time. I wouldn't consider patching up a torn pouch but I see no issue with repairing a wire that got torn off. As long as the cell itself hasn't been crushed or the seal compromised it should be fine. If the seal is bad, the cell will likely start to puff after a few days and then you know it's toast.
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Old Jul 22, 2014, 10:04 AM
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USA, AZ, Gilbert
Joined Jan 2006
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I lost a plane from a simular damaged tab as the OP has. That is why I stated it is probably a gonner.
My pack was a 5S 5000. I "thought" I had enough solder on it to hold the main lead to the tab. I did...until I did a vertical climbout and the high continuous amps caused the repair to get hot and fail. Granted, I knew it was marginal but it was the best I could do with the little piece of tab left.

Rick
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