Having a hard time soldering A123-26650-M1A batteries

[markz]

I have tried a dozen times now to solder the positive side of A123-26650-M1A batteries and I am having no luck.

I tried Rosin core 63/37 and 60/40 solder, 95% isopropyl alcohol with horse hair brush, and tried using this RA Rosin Flux
I am getting solder that does not stick, or if it does stick it doesnt take much to get it off once its hardened. RA Rosin Flux is sticky, but seems to sweat well, I just havent had any luck with it, takes more to get it off. Plus with that stuff I need a special cleaner product. One thing I did not use at the very start was some of this spongey green scrubbers or maybe use a very fine sand paper. Then I'd clean with isopropyl alcohol, let dry then solder.

I am really at a loss as to what to do next, I was hoping to get it ready to ride this weekend, thats why I decided to solder. I would never do this on brand new cells, these are old M1A cells. I am a few days away from having my tab welder ready. Figured I'd go hunting today, but its miserable out.

Any suggestions on what to try next to solder these cells?

 

[www.recumbents.com]

Go get yourself some liquid flux for soldering copper pipes. It's mostly acid, so be careful. Works great.

 

[Occam's Laser]

You could try high end silver epoxy too: http://www.amazon.com/MG-Chemicals-Conductive-Extreme-Conductivity/dp/B018AAT4VC/ref=sr_1_7?s=industrial&ie=UTF8&qid=1453580131&sr=1-7&keywords=silver+epoxy

Just make sure you keep the bond line thickness low, keep it under pressure for half a minute after sticking the inter-battery connector on it.

 

[Diesel Dave]

Soldering master:

http://youtu.be/IelXfcrIXCc

 

[Occam's Laser]

OP you ever get this resolved?

 

[markz]

No, it went bad and got worse, no fireworks, but I am not sure about the amount of heat the cells recieved.
Pack is into pieces now, holders broke probably due to the heat.
I thought I was doing well, solder joints looked good, but when holders starting breaking loose, I broke off more holders, twisted a few joints and they broke off too easy, went like that for about 4P times 4S, my one white wire that I thought was superb, 2 cans broke off that. Another P of solid copper household wire held up with 2 cans. I must say though, it took me some time to make the surfaces of 4 batteries smooth again. 4 solder joints, gobbed huge mounds of solder stuck. Didnt want to sand down leaded solder, but managed to solder wick them off in 4 minutes a peice.

I am done trying to solder these b!7@h'es.

My soldering iron had issues with the end screws holding in the tip, basically broke the unit, slip-in thingy for screws twisted and broke one of 2 wires in some thick insulation to make it useless. Using now a Weller 100/140W with a friggin huge tip, I thought my other ones were big.

Its a holiday today, figured I'd go on the hunt for any old transformer out of a microwave to finish my battery tab timer welder. But sitting here thinking about it, my nickel strips, some 5mm magnets and epoxy are looking mighty fine. I am short on neo-magnets though. I would have had a two fold system. Epoxy would have kept the strips from moving. Heck heres a picture. Then sandwich it with a board. Just dont want the magnets to move and short out. Magnets are too long should have bought 1mm, or 1.5mm (H) by 10mm (D), would have been better fit.

I found some paste at Home Depot, couldnt find liquid stuff. That could have been the issue too.

Im done trying to solder, heres the pic of my ponderings.

 

[Karolis]

If you are trying to solder these. You should use at least 80-100W soldering iron with flat end. You have to transfer as much heat as possible in very short time. You must use Acid flux. I had soldered 300pcs of these 6 years ago. It is not the way to go but... at that time it was only that way.

 

[Occam's Laser]

That sounds like a giant pain

If you didn't catch it from the first post (don't want to be an a@@ but most people haven't heard of this stuff) silver epoxy is itself very conductive, easily conductive enough for a123 cells at 25C discharge (and don't get the cheaper stuff! It has ~10x the resistivity!) if you use it make sure you properly clean the surfaces first, minimum bond line thickness is 1/2000 of an inch if I recall, I doubt you'll be able to get it that thin but if you keep it less than 10x that it should work well, magnets probably won't work nearly as well on the cathode side as they do on the anode side.

 

[markz]

If you are trying to solder these. You should use at least 80-100W soldering iron with flat end. You have to transfer as much heat as possible in very short time. You must use Acid flux. I had soldered 300pcs of these 6 years ago. It is not the way to go but... at that time it was only that way.

I thought I had an 80W iron, but come to think of it, it must have been a 60W, I will try to find the web page,
http://www.princessauto.com/en/detail/powerfist-adjustable-heat-soldering-iron/A-p8103590e;jsessionid=lquBEJJHZTQEouyi-QmSPffi.pal-prod-com1
5-60W - Now I know what the issue was.

I have an old Weller 100/140W dual trigger iron, that would have worked.
http://www.homedepot.com/p/Weller-100-Watt-140-Watt-Soldering-Gun-Kit-8200PKS/100085564
2 kinds of tips,
http://www.be-electronics.com/SearchResults.asp?Search=weller+8200
Also got a flat blade type, called Cutting Tip, looks like a spoon,
http://www.sears.com/weller-tip-rope-cutting-for-8200-1-each-rct/p-SPM2640857421?prdNo=9&blockNo=9&blockType=G9

Acid flux

This isnt acid flux?
http://www.be-electronics.com/product_p/835-100ml.htm
called rosin flux. Must be a difference.

I might give it a go with my Weller and if I can find Acid Flux. All I could find is Paste at HD copper pipe section.

silver epoxy is itself very conductive, easily conductive enough for a123 cells at 25C discharge (and don't get the cheaper stuff! It has ~10x the resistivity!) if you use it make sure you properly clean the surfaces first, minimum bond line thickness is 1/2000 of an inch if I recall, I doubt you'll be able to get it that thin but if you keep it less than 10x that it should work well, magnets probably won't work nearly as well on the cathode side as they do on the anode side.

Yeah I have read up on epoxy and dismissed it, might have to read up on it again.
http://www.mgchemicals.com/products/adhesives/electrically-conductive/silver-conductive-epoxy-8331/
14g $60
"Potting" - http://www.be-electronics.com/category_s/1871.htm

 

[999zip999]

Look up weller 80watt soldering iron. BIG FAT TIP. What happened to your new spot welder ?

 

[markz]

Still working on my tab welder, the board itself is almost done, except my 100/140W Weller has tips that are too big. I have 3 small caps left in tight areas. I just picked up 1400W, 1100W and 900W MW transformer from the dumping off area behind Value Village, those MWT's should work. I have a side project which is to build a metal welder out of two 1400W MW transformers.

I still have not been able to find Acid Flux, been to Canadian Tire, Home Depot, and Rona. All I ever see is solder paste. Found some Acid Flux online, http://www.amazon.com/Alpha-Metals-AM51022-Acid-Flux/dp/B00182QQHA

 

[999zip999]

Are you talking about a solder gun 100/140watt. Those don't hold enough thremal mass. Big Fat Tip.