Battery capacity drop

[awol]

I've made up loads of 18650 packs. For what it's worth, here's my method:

1. Tin the wire first.
2. Now apply a liitle flux to the battery, and get it clamped.
3. Get a blob of solder to flow onto the battery. Make sure it flows.
4. Place the tinned wire on top of the battery terminal, apply iron, and again ensure solder flows.

Thanks Mike, I never got past No1 as the wire I tried was the solid bendy ringmain stuff. I will try again with some stranded copper out of an extension cable next time.

 

[Alan Quay]

Ah, ok. In that case, new steps no. 1 and 2:

1. Don't use solid bendy ring main stuff.
2. Do use the stranded copper out an extension lead.

 

[Khumarahn]

Couldn't get the solder to stick to that piece of single copper wire...

What kind of soldering iron do you use? You have to be using a strong one with a big tip (part of the reason is that soldering on the battery should be quick). It also good to have a drop of solder on the soldering iron tip, it greatly speeds up the transfer of the heat. And it would be useless to solder on metal, because all heat would be lost to it...

Also try to clean your joints with isopropyl alcohol from what remains of the flux.

 

[Khumarahn]

bendy ringmain stuff

it may just refuse solder, like nickel-chrome or aluminium...

 

[awol]

What kind of soldering iron do you use? You have to be using a strong one with a big tip (part of the reason is that soldering on the battery should be quick). It also good to have a drop of solder on the soldering iron tip, it greatly speeds up the transfer of the heat. And it would be useless to solder on metal, because all heat would be lost to it...

Also try to clean your joints with isopropyl alcohol from what remains of the flux.

I tried a 40w flat blade soldering iron then a pointed 50w variable one on full, then a gas flame torch then I gave up.
I have been looking for some isopropyl alcohol today in town and could not find any,I don't know where to get it. Any ideas?

 

[Khumarahn]

I couldn't find isopropyl alcohol locally. You could get this one: http://www.amazon.co.uk/gp/product/B003D8QFR8

40-50w may not be enough, but I don't know. I use a butane soldering iron which is equivalent to about 120w, when on full, with a thick and broad flat tip. The flat tip should transfer much more heat than the pointed one. I wouldn't solder with open flame, I tried once but had zero luck.

 

[Deleted member 4366]

I don't believe that alcohol will work. Instead, take any surface coating off with emery paper of a file. Just in case you were too quick, you need to allow enough time to heat up whatever you're soldering too

 

[Alan Quay]

I do mine with a 25w Antex. You really don't need any more.

 

[Khumarahn]

99.9% rubbing alcohol worked for me... after some rubbing

 

[awol]

Thanks all for the soldering tips and help. I've spent all this evening having another go at soldering the solid type copper wire and achieved this :-
What I did different this time was ruffed up the wire surface a bit with emery paper first and only tinned just over an inch length(instead of several inches like the other day). Don't know yet if the batteries are still ok or whether I kept the heat on too long though.
Then wiped over with the alcohol liquid to clean it up. Very pleased.

 

[Deleted member 4366]

Another thing while I think of it. Don't use lead-free solder for difficult jobs. Stick ti 60/40 tin/lead.