Convert flat top cells to button top

[uofaengr]

I was wondering what is recommended around here to convert flat tops to button tops besides solder? I've used a little folded up piece of aluminum foil before just playing around, but am sure there's a better solution.

 

[Str8stroke]

This has been covered a zillion times. lol

Some use solder, some use powerful magnets. I do magnets with super glue on the outside parameter. Don't use just the magnets. They can slide and cause a short on the body. Foil could easily cause a disaster too. I caution you there.

 

[uofaengr]

The magnets with the glue sounds like a good idea.

 

[m4a1usr]

I have been using the brass pads from International Outdoor for a couple years without issue. There are several on their website but I recommend the SKU D050 version. A bit spendy IMO for the fact you only get 2 with each order BUT they work great and shipping is free if you order 3 pairs. There is a best manufacturing technique I would recommend prior to making the decision to add these to your cells. You will need a heat source that will get the soldering of the brass pad in as short as possible time frame. And you will want to cool down the soldered area immediately using a Q-tip and some alcohol. Since these cells are known as cylindrical plate wrapped design you do not want to damage the cells internal plate. In this case it would most likely be just the anode but the damage could also extend to the insulator that separates the anode from the cathode. Some method of removing that rapid increase temperature IMO is mandatory.

 

[yellow]

check You light.
when it is single cell and has raised "+" contact inside (or a spring there, too), no button top conversion needed

 

[N4aeq]

I save old AA batteries, peel back lip around the top rim, the top hat can easily be removed with a putty knife and a tap on the handle. Then you can solder it the way that's bet for you, I use small solder wick braid, solder to the inside cup of the top hat then other to the flat top 18650, the short braid should fold down enough to add a dab of glue.

 

[ChrisGarrett]

Quality cells that have had button tops added to them in a proper manner really aren't all that much money.

Save your flat top cells for lights with springs, or raised contacts and run button tops in lights that do not.

You can find a bunch of them, there:

http://www.mtnelectronics.com/index.php?route=product/category&path=59_88

Chris

 

[Pöbel]

I just solder a small steel washer to the top of the cell. Quick job and not really much heat required.

 

[Str8stroke]

I save old AA batteries, peel back lip around the top rim, the top hat can easily be removed with a putty knife and a tap on the handle. Then you can solder it the way that's bet for you, I use small solder wick braid, solder to the inside cup of the top hat then other to the flat top 18650, the short braid should fold down enough to add a dab of glue.

Thats actually a idea I like. I may give that try.
73 Charles.

 

[N4aeq]

Yep,
Favorite thing for hams is doing something for nothing.
73s from n4aeq

 

[widucl]

Does the hole in the washer cause a problem?

Dalton

 

[Timothybil]

A couple of the battery vendors sell wrappers and button top washers, for those that want to rewrap cells. I received a bunch of 30Qs that were supposed to be button top, but were flat top instead. I bought some small powerful magnets that were the same diameter as the button tops. Pop one of the magnets on the end of the cell, then placed a self-adhesive washer over it so the magnet stuck through the center hole just like a button top would. Worked great. There was some concern from others when I shared this in another forum, but I tested by wacking the 30Qs against the palm of my had quite violently, with no ovement of the magnet.

 

[WalkIntoTheLight]

A couple of the battery vendors sell wrappers and button top washers, for those that want to rewrap cells. I received a bunch of 30Qs that were supposed to be button top, but were flat top instead. I bought some small powerful magnets that were the same diameter as the button tops. Pop one of the magnets on the end of the cell, then placed a self-adhesive washer over it so the magnet stuck through the center hole just like a button top would. Worked great. There was some concern from others when I shared this in another forum, but I tested by wacking the 30Qs against the palm of my had quite violently, with no ovement of the magnet.

Probably fine for single-cell lights, since there's not much force on the positive end to cause movement.

But be careful in multi-cell lights if they have a battery compartment that might cause twisting of the cells. For example, the BLF-Q8 is really bad for that, as the cells slide across the positive ring in the head when you screw down the tail. This puts lateral forces on the battery positive ends, and could easily cause the magnet and the washer to slide off. If that happens, the magnet could either slide under the insulating ring and short the cell, or it could tear the wrap and that could short against the flashlight's brass ring.

IMO, a solder blob is the safer way to go, if you can't get real button-tops.