Soldering Battery cells into battery packs

[Guest]

I need to make a small custom battery pack, 5 x 1.2 volt nimh AA cells in a side by side humped backed battery pack. I just wondered what sort of wattage iron would be best to use and how long I can hold the iron on the cell to solder the tag on, without the cell venting ni mh!

:thinking:

[Guest]

I've not tried nimh's but did use a 50watt iron to solder Sub-c ni-cads years ago.

You needed to file the base and use plenty flux, even then, i often resorted to the old fashioned copper 'Iron' and the gas stove. You will need to keep contact for about 5 seconds to make anything like a good job, the best approach was to pre-heat the cell until it was warm to the touch, then apply the iron (mine is an old 24 volt temp controlled job), standard 25 watt mains irons were a waste of time.

I often found that some cells would take the solder quite well, others were a real pain and never inspired confidence, they still worked though, at least on a standard 540 type motor which draws about 5amps max in normal use.

Sorry i cannot comment upon Nimh's, i'm guessing that there is little difference.

J.

[Guest]

i have soldered D type cells in Nimh format, i clean up all surfaces, i lightly abraded the cell with my trusty dremel, used plenty of flux and then used a huge old 200watt iron i picked up at a car boot,you need about 3 seconds, thats all that was required !

cleaning the cell ready for pack contstruction is the key to it.....

[Guest]

Bit of a pain though - the pack I purchased had the cells clustered in a square rather than a proper hump pack battery. I had to reconfigure the cells but when i broke them apart the celophane insulation on the cells came off with the super glue, now I have to bind them all up in tape! Was hoping for a neat job!

200 watt sounded a little higher than I was expecting? I guess it's a case of heating it quickly with a dab of solder. I'll have to fire up the old proxxon grinder too.

[Guest]

Good luck with the soldering ....... I would think you have a 50:50 chance of destroying the nylon seals on the cell by soldering onto either the base or cap since the nylon will soften at below soldering temperatures thus losing its sealing properties.

Personally I'd only ever solder a cell with solder tags, having knackered several cells in the past!

When I make up a pack I bind it with good strong elastic band and then squeeze a goodly amount of silicon sealer between the cells. Once set, I then take off the rubber band and wrap in insulating tape. You can use the 'self vulcanising' tape (Maplins have got it) since this self bonds. Mind it is expensive and so far I have never had a problem with the old insulating tape so ....

At any rate, best of luck!

[Guest]

soldering iron

Hi Guys,

I know this is a little late but, my local model shop use a funny shaped soldering iron.

It is shaped like the head of a hammer head shark (double ended).

The iron is 250 watt, this is so the soldered area heats up fast to prevent heat soak.

The cells are placed in a nylon type material channel, this lines up the cells. One end has a stop the other end has a sliding stop that is spring loaded.

This unit is adjustable for different size cells or number of cells, the cells are put in this rig and pushed apart against the spring tension.

The double ended iron is put in between the two cells which are pushed against the iron by the tension spring.

The fluxed solder is applied to the two ends of the iron, when the solder is seen to wet both cells the iron is removed and the cells shut together under the tension spring force.

Hey presto two cells soldered together.

They tell me it is important to have a soldering iron of the right wattage, to small a wattage will heat the cell but the solder wont take.

Hope this helps in some way.

Regards

Abrad

[Guest]

When soldering batteries - or, more correctly, cells to make up a battery - speed is of the essence, high heat, quick dab. Cleanliness and flux are both vital, light abravsive cleaning and pre-tinning with an active flux essential. The flux which works perfectly is the traditional Bakers Fluid, a hydrochloric acid solution, but you must put just one spot where you are intending to pre-tin - and don't use cored solder, use conventional plain 60/40 tin/lead alloy. The problem with an active flux is cleaning off any residue - not that there should be much if you have just applied one careful spot but if you have slipped up then a damp (not wet) cloth dampened with a little bi-carb solution is the (boring) neutralising answer. The perfect flux is hydrazine hydrate, totally non-corrosive but an active flux especially useful when soldering nickel - as you almost certainly will be. You can spill it and you don't have to clean it up but don't let this lead you into sloppiness, spillages of anything are not very clever. The only problem with this flux is I have no idea where to get it these days, I no longer live in that world. Incidentally, you pre-tin both faces of course then lterally just touch them together with your high-heat iron and you have a flowed joint. But if anyone can let me have or tell me where to get hydrazine hydrate I would be grateful.

Tell us if you have managed the job and how please!

Regards

LINNEY

[Guest]

Hi,

The guys at my model shop state that the cored solder they use is designed for the sole purpose of soldering cells. The owner of the shop gave me this information over the phone today and will give me the name and where to obtain it in the week.

Regards Abrad