Author Topic: Soldering  (Read 1489 times)

Offline Cantclimbtom

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Re: Soldering
« Reply #25 on: October 26, 2021, 07:19:21 pm »
As mentioned the bottom is embarrassingly shoddy - a real horror show, but electrically (and mechanically) good. I'll be pleased when that mess gets hidden by shrink.

But the top is burnt to a cinder by my attempts, non so far have stuck



Maybe Tom's arc welder will work, if nothing else it might ignite them and then I'll have a better excuse for not having completed a bit of "simple" soldering. I had no idea I could make such a palaver out of soldering 3 batteries
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Offline shotlighter

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Re: Soldering
« Reply #26 on: October 26, 2021, 08:53:44 pm »
Hi Nick, yes a good question. Its a tin of paste which I have been using since about 1965, no kidding. Its called "Fluxite Soldering Paste" and its tends to, well, last.



While you can get away with using Fluxite on battery terminals, under no circumstances should it be used for general electronic soldering. It's an acidic flux and will rot soldered joints.
Strictly, electrical joints need to be washed to remove its acidic residue once the joint is made. On electronic circuitry this is not usually practical. Unwashed stuff as big as battery terminals, with a relatively short life, the batteries probably fail before the joint. Hence "getting away with it".
 If you were caught using it anywhere I've worked you'd get yer arse kicked!

Online wellyjen

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Re: Soldering
« Reply #27 on: October 26, 2021, 09:48:08 pm »
As others have said, these sorts of batteries need a big high power iron to get the terminals up to temperature as quickly as possible before the battery chemistry itself gets a chance to overheat and do horrible things and the terminals oxidise. Spot welding is the ideal method for attaching leads, or tabs to them, but solder can be made to work. A more aggressive flux can be got away with here as you should be able to wash it off after. I've succeeded with these by tinning the connection tab and the battery terminals separately first, then sweating the two together, using regular no clean flux cored tin/lead electronics solder and a mighty gas powered soldering iron, rather than the usual low watt electric one. 60/40 tin/lead solder melts at lower temperature than the unleaded stuff, so use that if you can.

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Offline Cantclimbtom

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Re: Soldering
« Reply #28 on: October 26, 2021, 10:01:47 pm »
Aahhh.. thanks. I'd unintentionally bought lead free solder, but hadn't realised that could be significant. I need every little help I can get and hotter melting solder isn't what I need right now
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Online nickwilliams

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Re: Soldering
« Reply #29 on: October 27, 2021, 01:21:41 am »
Given the right flux and the correct solder you can solder pretty much any metal, even aluminium. You will need something a bit fancier than Fluxite paste and lead free plumber's solder for this job.

Where in the world are you? I have the flux, the solder and the iron, but you'll need to come to Hucklow to use them.

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Offline droid

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Re: Soldering
« Reply #30 on: October 27, 2021, 05:26:26 am »
Would low-temperature solder railway modelmakers use on brass models work?

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Offline royfellows

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Re: Soldering
« Reply #31 on: October 27, 2021, 10:52:51 am »
Soldering direct to the cells certainly does no good to them, the amount of harm is debatable and relates to the amount of heat put into the cell. A good high wattage iron makes it a quick job with the heat remaining local. Messing about in a way that keeps heating up the cell should be avoided.

I have now been building and selling lamps since 2008 and the biggest factor that influences battery life is current hit. I am aware of lamps, of more modest output, that are still going after many many years of service still on original battery, on the other end of the scale my own X16 has just had battery failure after 3 years and not all that much use.
Not on my own here. The high power torches such as the Imolent DX 80 are the same, I own one and replacement cost me £90
I am currently redesigning the X16 with replaceable battery rather than sealed rechargeable so battery replacement will be cheap.
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Offline royfellows

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Re: Soldering
« Reply #32 on: October 27, 2021, 11:39:08 am »
I have just tried to upload a photo of my soldering to a cell. Neat little solder, no burns, cell did not even get warm, done in 5 seconds, clean enough to eat off, but the bloody good old "failed security checks" garbage.

I give up.
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Offline royfellows

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Re: Soldering
« Reply #33 on: October 27, 2021, 11:45:46 am »
it has been said that a picture is worth a thousand words.
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Offline royfellows

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Re: Soldering
« Reply #34 on: October 27, 2021, 11:48:00 am »
I tried uploading as off the camera without resizing in photoshop.
So there you are then, and the cell did not even get warm as the whole process took seconds.
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Offline Fjell

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Re: Soldering
« Reply #35 on: October 27, 2021, 12:01:10 pm »
For the casual constructor like me, then buying them with the tabs on saves no end of arsing about. I tried once without and it was very hard with a normal PCB soldering iron to get something reliable - ie I ended up binning it as a bad job after building it but not liking how it looked at all.

The only wire you need is the one from the controller to the lamp if you do this, which seems better to me (assuming a 4V pack, the 8V one needs the intermediate connection).

I used 18500's from Ampsplus with the tabs on. They now do a 2.3A/hr version, which gives you a near 7 A/hr pack with 3 of them - pretty good for a Duo conversion.

https://www.ampsplus.co.uk/ampsplus-18500-2300mah-4a-battery


Offline royfellows

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Re: Soldering
« Reply #36 on: October 27, 2021, 12:47:48 pm »
I have just received a batch of Sanyo NCR 18650GA 3.6V 3500mAh from FastTech. They all tested at 'factory voltage' bar three which tested at 4.12V suggesting that these have been charged. I have marked them thus and put them on one side as suspect.
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Offline royfellows

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Re: Soldering
« Reply #37 on: October 27, 2021, 04:00:05 pm »
I have been sent this image by 'Wormster' if you remember him from AN, and he suggested me upload it. You can all see whats inside and maybe get an idea how to work with them?
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Offline Cantclimbtom

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Re: Soldering
« Reply #38 on: October 27, 2021, 06:55:41 pm »
Thanks Roy, I can see what I was cooking with the iron. What's not clear (to me) from the pic is how it's made. Looking at the layers, is it rolled up like a loo roll/Swiss roll, is that what it's showing?

I followed aricooperdavis suggestion to drill a hole in the button top, with your suggestion to pry it off as my plan B if the drilling didn't work. That allowed me with lots and lots of heat and flux to feed the wire in and solder the tops. Thank goodness!! I don't know what that button is made from, but it has magical super powers for repelling solder.

Very relieved to shrink wrap it up. Next time I'll try to get ones with tags first choice and second would be flat at both ends, but never again button top if I intend to solder it, that's a mistake.

Never Again


The Mrs' hairdryer isn't ideal for shrinking the battery wrap, but it sort of worked (just don't tell her I borrowed it)
« Last Edit: October 27, 2021, 07:10:13 pm by Cantclimbtom »
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Offline Cantclimbtom

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Re: Soldering
« Reply #39 on: October 27, 2021, 07:13:21 pm »
Lastly...  thank you very much to everyone for your advice and the various offers of help in the thread!  :thumbsup:
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Offline royfellows

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Re: Soldering
« Reply #40 on: October 28, 2021, 11:23:00 am »
I have been thinking on this from your pictures. In the nicest possible way I have to say that with the amount of heat you have put into the cells I would seriously question the safety aspect. If you use them , consider recharging in a safe place where a fire could not be started. Back yard etc.
I am not taking the pee, but have genuine concerns.
Dedicated lithium ion chargers - management circuits will not allow an over discharged cell to recharge, but I am thinking in terms of other cell damage.

If your cells are parallel, surely it would be better to use spring loaded battery holders?
The problem with these is if they are serial, a jolt can cause a temporary disconnection causing a multi mode lamp to change modes on you. This issue would not arise with parallel cells.

Also, the shrink wrapping will not keep water out. Stenlight found this out in terms of customer complaints which is why they redesigned their batteries with sealed plastic cases. Water tends to find its way in along the cable route. Of course, if you are enclosing your battery pack in a sealed case, this caution becomes unnecessary.

I like to see people having a go, and try to help as much as possible.
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Offline Ian Ball

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Re: Soldering
« Reply #41 on: October 28, 2021, 11:39:47 am »
Actually looks pretty tidy wrapped up.  Can you charge it in a way that measure current to determine if the solder process has reduced capacity? Might be worth knowing.

The 18650 cell is two sheets of material with an insulator membrane in the middle,  65mm or wide and a metre long, then it's rolled up and fitted into a can.


Offline Cantclimbtom

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Re: Soldering
« Reply #42 on: October 28, 2021, 01:21:07 pm »
Thanks Ian -- I'll compare the current for the wrapped 3 against the current load of 1 battery and check that the two numbers relate roughly as expected

Roy -- I was worrying the same thing and will charge cautiously by the back door, not under the end of some curtains and then forget about them and go out to the shops, as I heard happen to someone in a very unfortunate story.
They are in parallel and yes I'm sold on the idea of a proper battery box, this is intended for use in a duo battery box.
Please be gracious and don't point out the cost of a 2nd hand duo + custom duo insert + the cost of batteries and wrap etc etc, the time spent bodging it with soldering irons and swearing in my kitchen, fire hazard all added up --> then compare that to the cost of having just gone and bought a Dragon EX in the first place, because if you did might be right, but it wouldn't make me happy. I suppose I got an educational experience from it?
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Offline Fulk

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Re: Soldering
« Reply #43 on: October 28, 2021, 01:52:21 pm »
I know next to nothing about electronics, so I've merely flicked through this thread quickly, but one question that comes to my mind with regard to batteries in parallel is  – 'When you charge them, now do you know that they are all getting charged, and that two arem't taking most of the current and leaving one dead?'

Offline ChrisJC

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Re: Soldering
« Reply #44 on: October 28, 2021, 02:16:24 pm »
You don't!

You rely on them all being the same age from the same batch, so they will age more or less the same.

But for sure one will conk out before the rest of them.

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Offline royfellows

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Re: Soldering
« Reply #45 on: October 28, 2021, 02:26:11 pm »
This situation could only arise if a connection becomes broken, as its not normally possible because they will each take a proportion of the output current of the charger. This current will vary, hopefully slightly though, due to slightly differing internal resistances of the cells. So you will have a first to get fully charged, then second, etc. As Li Ion cells are charged at a constant voltage of 4.2V, when a cell reaches 4.2 V there is no voltage overhead so current cannot pass, but its desirable for the charge to cease and this will happen with a dedicated charger, any LED indicator will go from red to green.
To directly answer the question, charging will not cease until all cells are charged.

Issues will arise if one cell is faulty as this will discharge the other(s) in a parallel array. But likewise in a series array of cells it will shut off the whole array on discharge when it reaches about 2.7V, and will also fail to recharge to the same level as the others, in this event the battery is scrap. In reality, when this happens the others would not be far behind anyway.

Just picked up on Chris's comment, yes agreed, but I would not expect anyone to mix cells from different ages etc
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Offline Fjell

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Re: Soldering
« Reply #46 on: October 28, 2021, 03:00:52 pm »
Thanks Ian -- I'll compare the current for the wrapped 3 against the current load of 1 battery and check that the two numbers relate roughly as expected

Roy -- I was worrying the same thing and will charge cautiously by the back door, not under the end of some curtains and then forget about them and go out to the shops, as I heard happen to someone in a very unfortunate story.
They are in parallel and yes I'm sold on the idea of a proper battery box, this is intended for use in a duo battery box.
Please be gracious and don't point out the cost of a 2nd hand duo + custom duo insert + the cost of batteries and wrap etc etc, the time spent bodging it with soldering irons and swearing in my kitchen, fire hazard all added up --> then compare that to the cost of having just gone and bought a Dragon EX in the first place, because if you did might be right, but it wouldn't make me happy. I suppose I got an educational experience from it?

Purely in a spirit of inquiry, do you have a BMS in there somewhere, or are those protected cells (ie it's inside)? If they are protected cells, you have put a lot of heat on the board. Might be worth checking they turn off by 2.5V (hard to check the 4.2V because the charger will do it).

Offline Steve Clark

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Re: Soldering
« Reply #47 on: October 28, 2021, 03:15:12 pm »
Commercially manufactured packs are spot-welded with short strips of nickel or nickel-plated steel strip. The current passes between two spots on the same terminal, so no current through the battery and very short duration so limited overall heat.

You can buy a 'battery spot welding pen' on ebay for about £15-20. Works on 12v from a car battery or similar. No idea on the reliability.

The strip itself is cheap. Search 'battery spot welding strip'

We have had some quite large packs for diving/suit heating manufactured this way. 12v / 70Ah. Same energy as a car battery, but only the size and weight of 4 cans of coke. We think quite carefully about where we charge those  :o

Offline Cantclimbtom

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Re: Soldering
« Reply #48 on: October 28, 2021, 03:19:58 pm »
Purely in a spirit of inquiry, do you have a BMS in there somewhere, or are those protected cells (ie it's inside)? If they are protected cells, you have put a lot of heat on the board. Might be worth checking they turn off by 2.5V (hard to check the 4.2V because the charger will do it).
No, I realised that was a good idea after I bought them. However with all my cack-handed soldering, maybe that was for the best?
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Offline Steve Clark

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Re: Soldering
« Reply #49 on: October 28, 2021, 03:21:51 pm »
Also, you can contact Strikealite and they will make custom stuff to order and/or copy other manufacturers or discontinued packs. Conveniently, they list them on the website afterwards so you can just order them if someone else has beaten you to it!

https://www.strikalite.co.uk/prodcat_type/20/ALL/0/Specialist_Battery_Packs.html

 

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