Soldering LiPo leads

Has anyone had experience resoldering LiPo power leads? I have a couple that have broken off. I now tape over new ones as soon as I get them to give mechanical stability, but too late for these ones.

Hi John
If you have had very little soldering experience don’t even think about it.
If the LIPO has a tag it should be ok BUT…use a good controlled iron of at least 350ºC or more for lead free. Solder the wire to the very end of the tag and if possible clamp something on the tag for a heat sink. AND DO IT QUICKLY. The whole idea is not to heat the cell itself. Someone to hold pointed pliers on the tag would be OK or a small pair of clamping forceps with a bit of copper tape in the jaws is handy.

Was the original soldered or butt welded. Welding has the advantage of only heating the very small area of the actual weld. Royston (USA) make a soldering iron that uses the principle of passing enough current through the joint to raise it to soldering temperature and the joint itself is the only bit that gets hot. Very expensive and not commonly available to the average user.

If it was soldered you have a chance of repeating the exercise but if not on a tag or you are not happy or confident taking adequate precautions to not heat the cell don’t even try.
Cheers Bob

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Thanks Bob.
I notice you mention “lead free”, does that mean it needs to be lead free?

I have managed to open out the circuit and I think it should be fairly easy to heat sink it.

What do you think?

Also most LiPo batteries have that yellow tape on them… Is this special tape or could I just use insulation tape?

Hi John
Your soldering looks it goes nowhere near the actual cells so even with minimal experience you should be fine.

NO. I only mentioned it as there is a tendency to use lead free solder these days. Gives one a warm feeling but is a good thing health wise if using large amounts commercially. For the amount you will use “normal” 60/40 alloy should be OK. But, if you have been using lead free and have it on hand by all means use it. It became popular (or mandatory in some circumstances) after I retired so I have had no experience with it but I think it needs a few more degrees iron temperature with a bit greater risk of overheating components so probably requires some soldering experience to use. I don’t think you would have any or you would have known what it was so don’t worry.

I think it is only a thin heatshrink. The down side of insulation tape is the sticky stuff, especially in hot weather. Will be OK though if you do a neat and tidy job.
Cheers Bob

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Thanks for that. I just thought “lead free” might be required so there was no electrochemical interaction at the joint. Will give it a go tomorrow. I might put some paper over the circuit before I apply insulation tape. That should keep it gunk free.

Cheers

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Hi John

No. I believe it is purely for health reasons.
I often have thoughts though. I grew up with “lead” pencils, there was a reason they were called that. Lead paint on houses and pretty much anywhere paint was found. All those things. I am now approaching 87 (next Jan) and think I am still going OK. Must have been lucky or didn’t chew too many pencils.
Cheers Bob
Quick add on
Petrol used to have lots of lead too

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