Anyone repair lipos with a torch?

[electr0n]

I just bought a benzomatic micro torch and I was hoping I'd be able to use it to repair some of my old lipo batteries. It comes with a medium sized soldering tip but it doesn't get hot enough to melt the solder on the battery. Just curious if anyone has used a torch for this purpose? I was thinking of taking the soldering tip off and just using it as a torch but I'm wondering if this is a dumb idea. I don't want the lipo to pop in my face !

I'm having a lot of trouble trying to heat up the solder on my turnigy packs so I can remove and replace cells. I had a 30 watt iron before and I made my own large soldering tip with some copper wire but it took forever to do and the tip lost effectiveness after a short time. Now I've got a butane torch but I haven't had any luck with it so far.

 

[Ykick]

Open flame pointing at RC Lipo is very dumb idea imo.

You need one of these and 60W iron to drive it:

http://hobbyking.com/hobbyking/store/__10803__Hammer_Head_Soldering_Tip.html

I've had mine for years and performed numerous RC Lipo brick surgeries with it.

 

[cal3thousand]

That's like bringing a 30-06 to hunt rabbits. Not needed and will actually do you no good.

 

[electr0n]

hmm I suppose I'll refrain from the torch directly on the lipo. I was hoping this thing would handle the job. Guess I'll have to get a big iron just for battery repairs.

 

[Ykick]

Big tip comes in handy for more than just battery tabs. Large splices/joints using 12-10ga wire flow like a champ. And it also nails 4mm and larger bullets.

 

[electr0n]

Appreciate the feedback. I think I'll keep the micro torch anyway. There's been a couple times I lost a connection on the road and had to take a long walk back home with the bike because I didn't have a portable soldering tool. I'm a bit surprised this thing doesn't get hot enough to melt the solder on the battery terminal though, maybe if it had a larger tip.

 

[spinningmagnets]

Go to a large hobby store, and then to the aisle with stained-glass window kits. I got a 100W soldering iron with a fat tip for $20 there, and I made my own stand from a steel coat hanger and scrap wood. http://endless-sphere.com/forums/viewtopic.php?f=16&t=49848

 

[dnmun]

i used a torch to unsolder the tabs on an A123 pouch to remove it from the series since the solder was too much for my two 40W irons and it carried the heat away too fast through the tab. even then it was hard to melt the solder and not smoke the pcb the tabs were soldered onto. requires 5 hands to do it with torch and two irons.

 

[MadRhino]

As long as your lipo cells are not leaking any gas, you should be good to solder them tabs with the small torch. Yet it is risky business, for you never know when a cell will start leaking and the gas is highly flamable. Best is to follow recommendations and use a powerful soldering iron with a heavy tip. Some cells, like the Zippy compact for eg., require a lot of heat and very corrosive flux, but most cell tabs will solder with 60w NP.

 

[crea2k]

Using a gas torch, even a small one next to lipo packs is a bit like using a match to illuminate your kitchen after a gas leak, explosion will happen ! lol

 

[dnmun]

Using a gas torch, even a small one next to lipo packs is a bit like using a match to illuminate your kitchen after a gas leak, explosion will happen ! lol

you people carry this lipo explosion stuff to absurd extremes. no experience but full of absolute certainty it will blow up for no reason at all.

the biggest problem with having a torch around the tabs is melting the mylar around the tabs on the ends but the A123 tabs soak up so much heat i could not melt the lead free solder without it.

 

[electr0n]

spinningmagnets, that's likely what I'll do. I hope it makes it a lot easier to melt the solder on the battery tabs. I've got a couple battery packs that have been sitting around for a while with just one bad cell each.

dnmun, I find many soldering jobs require more hands than I've got. I need one of those helping hand things. I tried melting the soldered tabs with the heat exhaust on my torch with the soldering tip attached. I wasn't brave enough to try the open flame. I found the cell was heating up a bit too much and the solder still wasn't melting. I also tried heating up a screw driver tip with the flame to act as a thermal mass but that didn't work either.

MadRhino, How would I know if my cells are leaking gas? Most of the bad cells I want to remove are puffing pretty good but the cells still appear to be intact.

crea2k, my torch has soldering bits so I don't have to use the flame directly on the pack, it's pretty well contained. I don't feel too unsafe using it like that but it's just not getting hot enough or there's not enough thermal mass on the tip to melt the solder.

I think I'm going to try one more thing, make a big soldering tip out of copper to attach to my torch. Maybe that will work better than the supplied tips. Failing that I'll just go and buy the proper tool for the job.

dnmun, I agree some of the lipo risks seem to be exaggerated here a bit. I had one fire with them in over 3 years of use and it wasn't all that spectacular really. It let out a lot of smoke but the flame itself wasn't much. It did not explode or anything close to it. I punctured the cell. No problems since then.

 

[crea2k]

It says on the packs to keep them away from sources of heat so id say a gas torch was fairly hot lol

 

[crea2k]

I have one of those too, should do the job with the soldering tip on as mine gets so hot it glows orange, I just wouldnt use naked flame on it, after watching many youtube videos with kids and lighters lighting lipo batteries.

 

[Matt Gruber]

for 1 connection i use JB WELD epoxy. CLAMPED gently for a good connection, set overnight.
JB at walmart auto dept. $6
good for 25-50 repairs.

 

[docnjoj]

The problem with those soldering torches (I have several) is that the tips are very thin and don't hold the heat. An 80 watt Weller with a hammerhead or a stained glass 200watt iron really make the best solder joints and don't give time enough to heat the battery, Just my 2 cents.
otherDoc

 

[dnmun]

depends on the solder, lead free has a high melting point and is now required in US sold products, and the A123 pouches have a 2" wide tab also that is so huge it takes several soldering irons to cover it, along with having to heat up the adjacent tab and the pcb.

i did not use the kinda torch with the iron on it, i used the open flame of my propane torch to heat the tab along with the irons to keep it melted once i got it hot enuff.

also i think the tab material on the A123 is about 2-3X the thickness of the little lipo tabs. it really does soak up the heat fast.

 

[999zip999]

My local hardward store has a 80 watt weller for 32usd fat tip.

 

[electr0n]

I could not find a weller for a reasonable price locally, except for the smaller under powered ones. So I grabbed an 80 watt iron from Canadian Tire. It's got a huge tip for stained glass. It did a good job melting the solder off the battery tabs and made the job ten times easier. I was thinking I had shit soldering skills all this time. Now I think I just had some shit soldering irons. Do the cheaper brands produce less heat as they age?

 

[docnjoj]

Most of us, (including dnmun, I'll bet) have a good supply of 60/40 lead solder around. The new stuff (lead free) is really hard to solder without real high heat. Low fusing solder for the win. I ran into this problem originally when I tried to solder 12 ga wires to my Fatpacks. They had that lead free Euro solder that simply would not melt. Applied some lead solder and the problem was solved. Just use adequate ventilation and leave the lead-free solder to the factories so they comply with ROHAS standards.
Simply my opinion but it works.
otherDoc