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soldering cells
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Nick
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I could be WAY off here, but my experience with silver solder is in making jewelery. This type of silver solder has much more silver and melts at a pretty high temp - you wouldn't want to try it on batteries! A solder with just 2% silver will have a lower melting point and should have fine conductivitity too - can't imagine why it's marked not for electrical use, except for the higher melting point damaging components.

The idea with ordinary lead/tin solder is to balance the hardnes of the tin with the low melting point of lead. The typical 60/40 mix is ideal for most electrical work. Solder with more tin is stonger but has a higher melting temperature, which is definitely what you don't want with your batteries.

Personally, I am going with the lowest temp lead/tin solder I can get. I figure that the extra lead will make the connections more shock resistant.

About the silver coating on the braid; it will be microns thick and is probably just there for corrosion resistance. It's not likely to up the current rating even though silver is a great conductor.
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Post Tue Oct 05, 2004 8:18 pm 
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timmeh
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Ok thanks.

With haveing more lead dosent that mean more resistanch as lead isnt a very good conductor?
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Post Tue Oct 05, 2004 8:25 pm 
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Ajax
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Just use the standard 60/40 solder, This will be fine for the battery pack. The 60/40 solder has a melting point of 183 deg C, so I would doubt the packs are getting that hot during a battle.. And follow Spockies tip.


quote:
Just a little tip I just discovered while practicing soldering some cells together..

Get your Dremel or Supertool and put one of those little pink grinding stones in it (I used the round ball one) and give the terminals on the cells a light scuffing with it of about the diameter you want to solder to flow to.

After you've done this, the solder just flows on as easy as, with no bakers soldering fluid (corrosive) required. Its so quick, I wouldnt even worry about overheating the cell, I can get a really good button of solder with about 2 seconds of heat.

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Post Tue Oct 05, 2004 10:23 pm 
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timmeh
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Iv just soldered 10 cells together with 2 strands of braided wire to be sure they will take the current im likely to pull out of em and i used a combination of 40-60 and 60-40 cos i run out of 60-40.

I managed to get a amature neat solder without the solder running threw the braid and makeing it a solid chunk of solder and the cells only had about 2 maybe 3 seconds of heat Very Happy

The copper braid cools allot quicker then bars Very Happy
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Post Tue Oct 05, 2004 10:30 pm 
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Totaly_Recycled
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Ive done a similar type thing when ive had to repair nicad race packs with similar results - getting the metal free from dirt oil and surface oxidants is the key to good quick soldering .

Post Tue Oct 05, 2004 10:38 pm 
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Glen
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okay now ive gotten all my cells to the same voltage (1.19v is all the triton would discharge them down to at 300ma discharge rate oddly) and ive scuffed the ends up with a dremel grinding sphere sort of attachment (and wrecked it, not surprising given its a $20 tool hehe).

oh yes disregard that PM too nick, i got the cells to charge/discharge.

sooo just so i dont bugger my packs i just want to make sure i have this all correct -

* i should use my gas powered soldering iron * using 60/40 is fine
* do not tin the braid excessively so it doesnt turn into a solid hunk of wire
* heat the cell and wire together at the same time, do not hold the iron there for more than 3 seconds.

not sure what is meant by the heatsinking idea, do you guys mean to touch the end of the cell after soldering with a piece of aluminium?
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Post Fri Nov 05, 2004 7:54 pm 
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Nick
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It probably doesn't make much difference, but I would heat the tinned braid up before touching it to the cells. That way,the braid is at sldering temperature before you start transfering heat to the cell and its likely the soldering between the braid and the cell will take less time and reslt in less call heating. Cooling the cell off as quickly as possible is definitely a good idea but I am not sure that contact with an ali plate will do much. To get good heat transfer between solid objects, you need plenty of contact area and since solder forms a very irregular surface, there will not be much contact. Its can't hurt, but you will probably get better cooling with high volme air from a hair drier on cold (or both). I still think the ultimate but messy cooling will be from dunking in a water bath.

I wouldn't recommend using super glue for holding cells together as its way too brittle. If you don't have a hot glue gun, try an adhesive that stays flexible. Tarzans grip or building glues like No More Nails stay flexy when they dry.
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Post Fri Nov 05, 2004 10:11 pm 
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Valen
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or duct tape
not that i'd know about such things ;->
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Post Fri Nov 05, 2004 11:40 pm 
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Nick
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Use only Nashua Gaffer tape! <salute> In Gaffer tape We Trust. </salute>
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Post Sat Nov 06, 2004 1:02 am 
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Glen
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not about soldering cells but more on general soldering..

i have bought this mystery solder (i was in a rush..) that had no markings on it and i have no idea if its the right stuff or not (60/40 rosin core) but let me give you some odd properties this stuff has -
* it melts very quickly
* ive gone through an entire tube in about 3 days of light soldering. i usually go through a 60/40 tube in a month or two.
* it seems impossible to tin wires with this stuff. usually i just warm the wire and push the solder in and it gets sucked into the wire, but this stuff just stays as a blob on top of the wire and wont get sucked in.. and the iron is f'ing hot.

does this type of solder sound familiar to anybody?
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Post Thu Nov 18, 2004 6:11 pm 
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timmeh
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Sounds like the resin\flux is of poor quality
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Post Thu Nov 18, 2004 6:17 pm 
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Ajax
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it sounds like you picked up some solder the doesn't have a resin core.
with out some sort of flux you will never solder any thing, it will just do what you explained.

To solve this problem you can get some flux and put it onto the area that you wish to solder.
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Post Thu Nov 18, 2004 7:01 pm 
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Nick
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It could be "Lead Free" solder. I tried a roll a few years ago and although it was a good brand and had a flux core, it just wouldn't flow into joints, much like your problem. I still have that roll after several years, while other rolls have been used up.

@ Glen: If you need some good solder urgently, I can cut a few metres off that roll of silver solder for Saturday - its the best stuff i have ever used!
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Post Thu Nov 18, 2004 10:14 pm 
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Glen
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i shouldnt need any nick, ill head out this arvo to try and get some but worse comes worse ill give you a call.
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Post Fri Nov 19, 2004 5:51 am 
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Glen
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found a few cool little tips regarding battery soldering today while making some drill nicad packs.

to get a ton of solder onto the cell while tinning heres a bit of a hint - roll the solder up into a little ball so theres a fair amount of solder, and then tap the iron onto the solder VERY quickly. it should slightly melt and as soon as that happens press the iron and solder down to the cell quickly and youll get a big pile of solder onto the cell within 2 seconds at most (towards the end i could melt the solder onto the cell in a second and it was cool to the touch in 5)

it also speeds up the making of the pack as you dont have to sit there with the iron on the cell applying the solder to it. it just all happens at once.
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Post Mon Jul 25, 2005 6:01 pm 
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