I just salvaged a button from a blown chinese 18650 for a panasonic unprotected —- to change a flat-top to a button top. Shrink tube holds it in place perfectly. Sure beats globs of solder on the pos. terminal and looks factory installed. Now the 18650 unprotected will work in my ke-5 and other lights without a spring insdie the tube, where flat-top batteries will not work.
Anyone have any CHEAP source for those 18650 battery buttons? I just started to look online but figured someone here has to have done the research already. NOT the whole protection circuit. Just the button top.
I wouldn’t want to try and solder a protection circuit on the bottom of a li-ion. Too much heat and too much risk of melting the li-ion innards. but the flat-top button is separated from the battery as a whole. I think I can quickly solder on some buttons —- if I can find any that is. Anyone know where I can find some? They gotta be cheaper than dirt (I hope). I imagine they have some little solder tab attached.
I don’t think they will have any solder tab. I think that they are designed to be welded to the battery, which is what I will do if I find some of the button tops.
>>>> I think that they are designed to be welded
>>>>>to the battery, which is what I will do if I find some of the button tops.
The one I salvaged had a springy metal tab that was soldered to the button top. The other tab end was soldered to the chinese flat-top and EASILY de-soldered. Because it is a flimsy, thin tab, it was also very easily soldered to the panasonic flat-top and then held in place with shrink tube. You could almost cut super thin metal from some source with tin snips and use that for the solder tab.
I could try just having the shrink tube holding the button in place without solder but I don’t know …. It might be kinda loose and an unreliable contact. Soldering is really really easy, if the buttons are set up like the one I pulled. I use hemostats connected to the flat-top button while soldering to wick away any heat before it hits the actual battery. Even 1 second after the soldering, the flat-top was pretty much barely warm, so I think the hemostats are doing their job as heat sinks.
Also looks like the button tops have some kind of adhesive rings around them to assist in holding the button-top to the flat top. Who knows where those adhesive rings come from. Hopefully they wil be part of the button-top assembly. i hope.
Well, my comments were based upon a sample size of one. I’s been a few years and I don’t even remember what battery it was that I took apart. Guess I’d better look at a few more button tops.
I have been soldering a small brass button to the battery for my one light that needs a button top.
I can't search since I'm on my phone, but if you find the thread about wrappers for batteries it is in there. Im talking about the trust fire 4000mah wrappers.
Magnets can shift and and short with the side of the battery compartment. I WANT the magnet trick to work, but it really doesn’t in any kind of safe reliable way. If that magnet slips and shorts the positive terminal with the neg battery compartment wall, you’re talking kaboom — BIG TIME kaboom, especially with an unprotected cell, which these are.
I tried a test and used a dead pack pull. Carried it in my pocket in a 501b or one of those … I forget which now. After a couple hours: Yup the magnet had jumped off the flattop and was mm from the compartment wall.
Yup. Epoxy works. Blobs of solder work. But they look sloppy and like well … blobs of solder.
I solder audio cables all day long, so soldering a couple button tops is no big deal to me, but yes it could be an issue for the soldering challenged. You do NOT want to overheat the battery with a soldering pen. The catalyst-filled bag in the cell could burst and you’d have the famous “vent with flames.”
The size is 1.6 mm circular magnetic spacer and provides a protrusion for one end of the battery, very useful for using 2 batteries in series. 1/16” tall x 1/4” diameter (1.6mm x 6.35mm) nickel plated neodymium disc magnet, poles on flat ends.
…to convert my laptop pull flat-tops to button tops. No soldering, the adhesive insulation disc isolates the ring and keeps it from moving, and the shrink-wrap holds everything in place nicely. I’ve never had any issues with shorting or cells not working using this setup.
Stacked as follows:
1. Use heat gun to shrink tubing on the cell, half the length of the cell.
2. Remove cell and drop large diameter (-) contact into end of pre-shrunk wrap.
3. Apply larger ID gasket to (+) rim of cell to prevent contact with button top cap.
4. Carefully drop button top cap into center of gasket on cell.
5. Adhere with smaller ID gasket to retain in place.
6. Insert assembly into partially-shrunk battery tube, and heat to fully shrink.
Do you remove anything from the battery, before applying cover caps, insulators and wrap?
Not even the original plastic tube?
Bonus question: do different kinds of caps (especially “top” ones) I see on Fasttech have to be used in different situations or do they all always work?
