Soldering cells together

Hi everyone

does someone know how to solder tagged cells together, my soldering iron is not up to the job.

Edited September 22, 200718 yr by Grizzly Bear

Hi everyone

does someone know how to solder tagged cells together, my soldering iron is not up to the job.

 

Hi Griz, you might find some useful info on this thread. Basically you need a beefy iron, I've done it with a 50W but I wouldn't like to try it with anything smaller. Most people agree that the traditional 60/40 tin/lead solder is easier to use than the modern lead-free stuff, it's hard to buy in shops but can be obtained cheaply on ebay. Try to be as quick as you can to avoid heat damage to the cells.

 

For future reference it's best to start a new thread if you can't find an existing one with an appropriate subject for questions like this, it helps to keep things on-topic. Just click on the new thread button in the upper left corner of the electric bicycles main index page, give your thread an appropriate title and you're away.

Hi Ian

thanks for that, I've been using a 100 watt trigger operated soldering iron, it must be faulty I think, it works ok for normal soldering, but I thought that it should be hotter than it is. Can I solder directly onto a cell without damaging it then?

a new thread created for you guys!....

Hi Ian

thanks for that, I've been using a 100 watt trigger operated soldering iron, it must be faulty I think, it works ok for normal soldering, but I thought that it should be hotter than it is. Can I solder directly onto a cell without damaging it then?

 

I think it must be faulty, I solder tagged cells with a 30 watt iron without any problems, though I have to let it recover between each application, so a more powerful iron is better.

 

It is possible to solder directly onto cells, but then a very hot iron is important, so that the contact can be a brief as possible. Using tagged cells is always better.

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I agree with Flecc, there must be a problem with your iron. Personally I've never got on with those trigger operated soldering guns, the U shaped bit doesn't concentrate the heat well and doesn't have enough mass to store heat.

A 100W conventional soldering iron would do the job with ease.

Hi Flecc

the thing is, I've seen 12ah D-cells advertised, but you cannot get them tagged. Are the beefy irons that Ian mentioned still available? I remember the electricians in work had them, but that was years ago.

 

Regards Griz

I've seen the 11 Ah cells, also button end, but I'm not confident of the quality of many of these cells when in series. The matching is important.

 

Larger irons are available ok. Probably the easiest source is Machine Mart either online or their local stores. Some of theirs are very expensive, but they have an 80 watt at £23.48 and a 130 Watt at £17.61.

 

Respective product codes are 040210082 and 040210147, which you can enter into code search on their site.

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Edited September 22, 200718 yr by flecc

Or there is this butane powered one at Screwfix

Hi Flecc

I had better brush up on my soldering skills I think, perhaps I should beg one off one of the electricians instead. 12 ah D cells! where is it going to end?

 

Regards Griz

 

12 ah D cells! where is it going to end?

 

Regards Griz

 

I don't know Griz, but I'd rather have 6 Ah C cells so I can have a very much lighter battery for moderate range journeys.

 

The poor old C cell size is getting neglected lately, all the action is in AA and D.

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I don't know Griz, but I'd rather have 6 Ah C cells so I can have a very much lighter battery for moderate range journeys.

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Me too. ..

Hi Both

how light are your bikes then? Mine tips the scales at 23 Kgs with the D cell battery pack.

My Torq was originally 25.5kg, improvements I've made have probably shaved a bit off that, but add a heavy duty lock and a spare battery and the weight is over 30kgs. But if i could save a bit on the spare battery which only ever needs to do a few miles...

Hi Ian

the weight I quoted includes my heavy duty lock and necessary bits and pieces of cycling too, I have also retained the 21 gears, which is very handy when your battery gives up on you. The Synergie Mistral is 30 Kgs with a basket and panniers, of course it's got a Lithium Ion battery, which helps.

The utility bike is the converted Quando, 25 kilos, see here.

 

I converted my Torq to a sporting only spec, and it's now 22.9 kilos. See here.

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Hi Flecc

your so funny! Ha Ha Ha

 

Regards Griz

Hi Guys

I bought a 120 watt soldering iron from Machine Mart, I've just tried tinning one of my batteries, and it was so easy, no damage done either. Thanks for the good advice. By the way have you seen the very cheap NiMH batteried Lidl are selling £1.99 for two C or D cells, £1.99 for four AA or AAA cells, the C cells are 4000 mah, the AA cells are 2700 mah.

 

Regards

Yes, they've been seen before Griz, but the question mark is on the discharge rate. Lot's of these cheap high capacity cells lack the high discharge rate necessary for driving our motors at full power, so they can perform poorly in bikes.

 

If the discharge rate is too low, they cells overheat, maximising the chance of a failure in a series of cells. Overheating like this can melt the soldered connections and lead to complete destruction of the battery. I've deliberately done this to a solder connection battery to show what happens, and it's not a pretty sight afterwards. The foot of this web page gives the details. Experimental AA battery.

 

So they may be ok, but there's a real risk that they aren't.

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Edited September 24, 200718 yr by flecc

Hi Flecc

that sure was alot of soldering you did on those cells, it must have taken quite some time. I'm pleased to hear that you've not had a failed cell as a result, I was a bit concerned at buying 30 cells at some cost, only to waste my hard earned cash. Regarding matched cells, is there any way that we can match the cells? I'm charging my cells to balance their voltage before I re-build my battery pack, but I know that's not the same thing.

 

Regards

That's all you,can do realistically Griz, it's not practical to measure cell impedance etc, and in any case you'd need quite a few spares to be able to reject for that.

 

I think just matching voltage, then part charging and part discharging only the first one or two times is enough to bring the cells roughly into line before going into full charging and discharging.

 

Manufacturers don't usually match, putting the onus on cell suppliers or departments to supply from single consistent production runs, and that usually works.

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Hi Flecc

tomorow we are having a soldering evening, you are of course invited. I found all those cells joined together when I stripped out my battery pack, a bit worrying, all that potential!! So I separated them all, now I have to join them all up again, and I'm not looking forward to it. At least I'll have 30 cells this time, my bike will go even faster! I think I'd better get my old crash helmet out!

 

All the best mate

Best of luck with that Griz, don't breath in the flux fumes!

 

As you say, it will be good to have the extra cell, which will give more power than you might expect pro rata. The loss of a cell the same disproportionate change, but to loss of course.

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Hi Flecc

you won't be surprised to know that I understand.

 

Regards

Of course! You won't be catching ZX10s, but it's be a load of fun trying.

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