Soldering

[aricooperdavis]

No idea   I'll have another go another day, maybe try drilling a tiny hole in the button to assist, if it's hollow maybe I can get solder inside it?

You should be able to see that it's hollow before you drill the hole, otherwise I wouldn't risk it Look at the little holes in this one, for example. You also don't want to completely block those holes, as they convert the potential bomb into a relatively less harmful catherine wheel/rocket 

 

[royfellows]

The iron I have is cheapo adjustable and lacks horsepower, I solder about once a year, this probably doesn't help but again the base of the battery would take more heating and the button top *presumably* would be easier?

Correct. I wonder if the button top is a different material. MMm, get a screwdriver and try levering it off, I am serious.

No idea   I'll have another go another day, maybe try drilling a tiny hole in the button to assist, if it's hollow maybe I can get solder inside it?

I wouldn't, try as I suggest above. Good soldering is essential. Drilling little hole will hold the connection but it will be a poor one and probably cause flickering of whatever you are building.

 

[speedycaver]

I have made many battery packs with every type of 18650 cell you can imagine and have come across this problem a few times.  No obvious reason for it, but generally I just throw a heap of heat in and get what I can.  It normally looks like bird sh!t on the top of the battery by the end but just about works.

I think I have had to throw away 2 cells where I simply couldn't get the solder to wet and had put so much heat in the cell I wasn't prepared to risk it dying and dragging the adjoining cells with it.  I have several flux's but neither seemed to make much difference, if it doesn't want to solder, it wont.

I like the idea of drilling a small hole, cunning plan.  I will try this next time.

 

[ChrisJC]

You need a decent soldering iron. One of those sh*te 15Watt ones without temperature control is going to be pointless.

You need to get a lot of heat into it, and fast.

Chris.

 

[tomferry]

You need a decent soldering iron. One of those sh*te 15Watt ones without temperature control is going to be pointless.

You need to get a lot of heat into it, and fast.

Chris.

I got a old arc that puts out some serious heat ?

 

[Cantclimbtom]

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

 

[shotlighter]

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!

 

[wellyjen]

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.

If you were caught using it anywhere I've worked you'd get yer arse kicked!

Me, or someone like me would be doing the kicking!

 

[Cantclimbtom]

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

 

[nickwilliams]

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.

 

[droid]

Would low-temperature solder railway modelmakers use on brass models work?

Sorry for the grammar.
Been on the beer.

 

[royfellows]

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.

 

[royfellows]

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.

 

[royfellows]

it has been said that a picture is worth a thousand words.

 

[royfellows]

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.

 

[Fjell]

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

 

[royfellows]

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.

 

[royfellows]

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?

 

[Cantclimbtom]

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)

 

[Cantclimbtom]

Lastly...  thank you very much to everyone for your advice and the various offers of help in the thread!