Custom Button tops. Very good to Unacceptable.NEED EXPERIENCED SOLDER BLOB EXPERT OPINIONS.

Batteries and Chargers Rechargeable Batteries
1

These are done by Three different people with varying results. I do have Three questions before I get started.

Is it’s safe to remove a solder blob?

Or can you add on to the existing blob?

Or are you stuck with what you got?

I will start with the Unacceptable.

He will remain nameless. He works for a battery dealer in the United states. He did two different types . The VTC5D are okay even though I had to do work on them.

The Samsung 25S are unacceptable to me. They look like a Sliver Beebee or a Ball bearing!

You will notice a rewrapped one in the photo that’s a flat top. That’s because the button top popped off the first time I put it in my battery carrier .

He claimed that the metal on that battery was different and the solder kept sticking to the iron??
He may be right, any of you guys have experience with button top on Samsung 25S?

I’m expecting the other Three to break off. I’m using it now with magnets on the negative end. It’s in a Four battery carrier. The Acebeam X65vn Mini.If/ When Another one breaks I’m not going to keep using magnets.

I give these SAMSUNG 25S an F

His VTC5D. He had two insulators on it with the top one being glued. It kept peeling off so I put another wrap on it. He said he does that for battery packs to make them safer?

I give them a C.

VTC5D

This was done in the warehouse at Liionwholesale by Dominic. These are VTC6,those are steel button tops that are welded on very very sturdy.

I give them an A+

VTC6

These were done by my friend and former neighbor Bob. He has Over 30 years experience soldering. He did a few dozen batteries for me these are the only pictures I have. I flattened the Dome with a file to make it even better connection.

Excellent job Bob. I give them an A+.

P26A and Apexium …Molicell P26A Rewraps?

What are your thoughts about my opening questions and on the jobs done by three different individuals?

2

The first ones look like cold solder joints; very shoddy. I’m not surprised to hear one popped off. The rest all look solid though

3

^

I don’t know anything about soldering. How can you tell the difference between a cold joint and whatever they are supposed to be?! What’s the other joint called? I’m not talking about pot!

What about the second one, the VTC5D. Are those a cold joint? He also did those . they don’t look too bad he claims it was the metal on the 25s that gave him a problems.

4

Spot welding a real button is the only acceptable solution. I wouldn’t pay for a blob of solder. You don’t know if the battery got damaged in the process or not.

5

I got refunded for these 25S batteries. Playing with house money.

I don’t know much about soldering but I’m very good at posing questions that’s how I learn.

So you’re saying they can be fixed, redone by being spot welded? How do you take off that Pinhead blob, without damaging the battery?

What makes spot welding safer? I’m just going to take a guess, a very small area is heated up instead of the entire surface of the flat top?

My friend Bob, with 30 years experience did a few dozen solder blobs for me with no issues at all.For FREE…Good friend. He did the 4 X P26A and 4 X apexium above.

Skill level has a lot to do with it as far as damaging the batteries.

I could see how batteries could be damaged by someone with an inadequate skill level and Limited experience.

I think these are okay in that regard cuz I’ve used them and did a capacity test. Not so sure I will be using them anyway. They’re in storage right now.

6

In order for solder to stick to a surface, the surface has to be hot enough and free of oxides. Otherwise hot solder will not stick and bead like the one on the first photo. The real problem is when those beads fall off. If you know batteries you would know how dangerous small electricity conducting metal bead can be.

The reason why spot welds are preferred is that there is no prolonged heating involved. In spot welding, only the small surface that are welded are heated and the heating is almost instant.

On the contrary, if you use a regular soldering iron, the whole battery can soak up the heat because you have to heat up the surface where solder is going to be put on. Of course if you use proper tools (high power soldering iron) and proper technique soldering can be quick therefore less risk of heating the cell. However, as a customer it is hard to know how the soldering is done. If batteries were heated long enough, it could be damaged.

Also, I suspect that not all spot welded button tops are the same. I think some button tops add significant amount of resistance. I have several button top 14500 batteries that were sold as bundles (from different brands) and internal resistance ranges from 40mR to 100mR. All batteries are purchased within two months so they are fairly new. I suspect the reason for the huge variation is the button top because I heard stories where removing the button top decreases internal resistance values significantly. I measured internal resistance using YR1035. I think it gives fairly accurate measurements.

7

Soldering requires heating up the surface to appropriate temperatures, usually few hundred C. This is completely incompatible with li-ion cells, so such “blob of solder” is always a fine line between too cold/falls off easily and too hot/causes damage to the cell potentially making it unsafe.

Spot welding is safe and is commonly used to assemble battery packs because it does not heat up whole surface - it heats up tiny spots extremely fast causing metal to melt, but amount of heat transferred into the cell itself is negligible.

IMO soldering on li-ion cells is extremely unwise and personally i would not try doing something like this or ever use a cell which has been soldered by someone.

8

As already said, get button top cells with spot welded buton, both Nkon and Akkuteile offer various button top cells .

9

Thanks for all the answers. My guess about spot welding was right. Less area Heated, less time applying that heat.

I don’t doubt that the spot welding button tops are better and safer.

With that said, my friend Bob I mentioned before, put blobs on dozens of batteries for me. Going back 8 years ago. None of them ever failed or exploded!

We do not live near each other anymore.

I can say with absolute certainty the dealer who did those 25S button tops will never have my business again! I wouldn’t even call him button tops. Looks like a oversized Pinhead on top. LOL.

I’ll continue to get my Liion wholesale button tops that are done professionally by Third party. They’re welded on there.

10

Here is a picture of the VTC5D, far left, 25S in middle( Both done by Dealer X) and P26A from Liionwholesale on the right.

11

Does anybody know if those 25s batteries I have can be fixed?

I have not gotten a clear answer on that yet.

I really don’t know who could fix them cuz Bob doesn’t live near me anymore. My single cell 18650 single cell lights are obsolete.

These batteries go to waste if they can’t be fixed.

12

This is why I had total faith in my friend Bob. Proper equipment, technique and 30 years experience. After everything was prepped, the batteries, the soldering iron heated up, it took him less than 45 seconds to do four batteries. :+1:

I wasn’t a customer. I was his friend standing in front of him while he did it.

13

Sure they can be fixed — not by someone who doesn’t know how to solder though —- most of the time you see that result without enough heat ( iron not hot enough)
I have soldered lots of cells both ends — you have to get in and out fast — the pos + is easy to solder but building up a blob takes practice

adding a tiny washer or piece of metal makes it a lot easier

14

How come I do not see any photos?

15

Hmm...

I don't know.

The images are hosted on postlmg.cc and I can see them.

16

Imho I used to be very concerned about telling people to solder onto a cell . it just seemed like such good practice .that said In the old days it seemed like there were more lights needing a longer cell and flat tops just wouldn't work on them .

Adding a solder blob for me was one of those game changer moments when I asked myself WTH was I ever thinking . It immediately solved lots and lots of dumb problems . Solder Blobs are easy and simple to do . IF you have flux and solder with lead .

I heard lots of people trying to find button top cells and missing out on great deals on flat top cells . Your friend did a nice looking job and the ones that look like a BB are pretty lame . That doesn't mean they have to look perfect ...The whole magnet thought is just a really bad one . If you need to be afraid of anything i'd be scared with a magnet on the end of a cell . it says you're not willing or able to do a solder blob ...and have defaulted to something worse instead

People have suggested taking a pile of old totally discharged/recycled 18650's and practice on them .

17

Thank you for your post. I wanted to hear from someone like you who’s done solder blobs for a long time.

There have been several negative posts about solder blobs. No doubt they can be dangerous and are not the best option.

Not many people can weld a button top on.

If you know what you’re doing like my friend Bob, who has done it for many many years and never had any issues, it has been proven to be safe.

I think it comes down to if you have experience, the right equipment and do not spend a lot of time getting the solder on the flat top. Like I said he did all four of them in like 45 seconds.

I have zero experience that’s why I had my friend do it.

The bb job is very lame and pathetic! When I opened the box on Monday I said WTF is this!

The magnet idea was one and done just to see if I could get it to work in the carrier.

18

I think Bob’s are ok…definitely got the solder flowing and hopefully didn’t overheat the cell or melt the can seal. Those 25S are…gosh. lol. Cold cold cold. It helps if you scuff up the surface enough to remove the nickel so that the flux and solder can work and do the job better…you could still do that. Negative is that once you remove that thin plating it can rust easily (often seen when grinding off tab welds on recovered cells).

If you have easy access to the button cap spot welds, absolutely do that all the time, imho.

One thing I do not like about the VCT6 that Liion did for you is that paper insulator. They’ve sealed up the vents (between the legs of the cap) and those are like that for a good reason. If a cell ever needs to blow off steam, it’s best to let that happen as quickly as possible, and an insulator like they used is just covering up the escape route. I see vendor-wrapped cells like this a lot now, usually protected cells, but it always bugs me. That said, I’ve never had a cell get angry except for shorts when separating packs…never in a device, though.

19

“Don’t solder directly on to battery”
-Literally every single manufacturer data sheet ever.

Heres what you do. Go on AliExpress and buy a bag of “battery tip caps”/”battery positive caps”/”positive battery buttons” for like $0.02 a piece. A bag of 100 is like $2. Two spot weld zaps to attach them, insulator, wrap, and you got perfect button tops like they came from the factory. Total cost, like 4 cents.

20

This is very dangerous fallacy and literally the reason, or at least major contributing factor, for very large portion of man-made disasters. Especially when complimented by complacency.

When you do something obviously wrong and dangerous and it does not blow up in your face, for hundred times, or hundred years, or whatever, it does not prove it is safe.

I mean this worked out fine too, but for some reason investigators were not impressed and recommended “psychological examination”…