Are the button tops on name-brand cells spot welded?

Batteries and Chargers Rechargeable Batteries
21

“DANGER
DO NOT USE OUTSIDE
OF BATTERY PACK”

is what it says on the VTC shrink wrap.
Those shrink wraps are quite thin and fragile too actually, easily damaged (this goes for all Li-Ion metal tube cells).
So i bought some of those plastic 4x 18650 boxes to keep them in.
But a battery pack?
Maybe it’s a 1S1P battery pack when you add protection PCB and an extra wrapper? :slight_smile:
…but i don’t use protected 18650 or 18350 cells…
Maybe i should…

22

@hIKARInoob, gauss163, Jerommel,

Thanks for the info,
New into the chargeable 18650’s only for the moment (more types will be added to “arsenal”) this via led flash-lights, so now I understand the reason.

But,
I would never have guessed it seeing the wast amount of business around it all with chargers, flash-lights, dedicated bike solutions and what not.

Also seeing items on shelf in well renowned store here in Sweden selling cells and flash-lights and so on I would not have guessed it. (repeating my self :slight_smile: )

I have my first protected cells with a top on order, but with this newly acquired knowledge it’s maybe a better idea to go with unprotected flattop cells and buy flash-lights with built in voltage protection or those that at least drop into moonlight on low voltage where those untampered flat-tops do fit/work.

You learn something new every single day.

-lyse99

Edit in,
More text.

23

To bad I don’t have a clamp meter and kind of a noob question but current in volts? or max amps it can deliver?
Like the 15A continuous and 25A temporary drops down?
If so howmuch you reckon?

24

Current it can deliver , in Ampere .

For example in one of my tests , in a blf a6 , with button top batteries from banggood i was reading 5.4 amps , and with the other home made button top 3.8 - 4 amps . Battery was fine (both 30Q) , but seems these buttons don’t make very good contact without being spot welded .

I didn’t make any further tests , because i find the “solder blob” method way easier now :slight_smile:

25

Right ok got it.

This is also not dangerous for either the battery or the high amp needing flashlight right?
For example a Nitecore TM16GT that runs 4 30Q’s with home made buttontops in series and draws arround 10 amps when on turbo.
It just means the flashlight cannot draw the amps it needs so the beam will not be as bright, right?

I ran my TM16GT with said 30Q’s and never saw a problem before, but just double checking here.

26

Not dangerous , but flashlight could be under-performing (only measurement could really tell) .

10 / 4 = 2.5 amps per battery , i don’t think you’ll have any issue .

27

For high currents a brass or copper pill soldered to the flat top will be ideal

Also adding a second heat shrink on unprotected cells is a good idea

28

A solder blob is enough .
If you make it nice square with a file , it will last forever .

Even my M43’s batteries are still great after lot of use on the light .

29

Aren’t you afraid copper dust and bits might fall inside the flattop and maybe make a connection with the negative part of the battery inside?

30

No , but now i will be :smiley:

Anyway , there are a lot of ways doing it . A pic from TomE : Photo and Video Storage | Photobucket

31

This is one thing I was always worried about when using a dremmel to remove spotwelded bits, from salvaged cells.
Used a compressor to blow inside the top of the cell, so either the bits would fly away or get stuck deeper.
I than put the cell away for 5 minutes and if they didn’t vent it was all ok.
I never had a cell vent for you information, so I wouln’t lose sleep over it.

32

Mine look better :stuck_out_tongue: :

33

I think my solder blobs are best. :smiley: :stuck_out_tongue:

34

That is a pretty one, i must say. :+1:

35

LOL. Is this battery-porn? Love those nipples on that one :heart_eyes:

36

i think we all like a good blob job…

37

if i dont want to spot welding. but i use little magnet to connected between flat top and a button.
Will it work?

38

Tried my hand at spot welding a button top on some 26650 Liitokalas and 30Q Samsungs. Worked better than expected with the amazing kWeld. It’s a bit expensive, but very consistent. Bought it straight from Frank at Kicksurfer who makes them. Got the button tops from Aliexpress

Measured internal resistance before and after: absolutely no change. 28mOhm for the 26650 Liitokalas, a very respectable 23mOhm for the Liitokala branded 30Q.

39

Good job maukka ! These look great !

40

Just came across this and it’s exactly what I need. Thank you for the photo