Any lights NEED a flat top 18650?? Or will button tops work in all 18650 lights?

I searched about this for a while and found no solid answers...

Since there are quite a few lights that only work with button top 18650, and all lights that work with flat top will also work with bottom top? It seems logical to only buy the bottom top 18650 cells from now on?

Unless someone can come up with a light that only works with flat top??

I would rather spend a little extra money (if needed) and have my batteries work in all my lights vs only work in some...

Am I way off base here? Just wanted to get some thoughts before ordering a bunch of button top cells.


Thanks.

Good thread topic and one which strikes a personal cord with me.

In my experience, the only time a flat top cell has been of benefit has been when coming across the odd light that cannot cope with the length of a protected button top cell, as both the protruding button and protection circuit elongate the bare cell. It seems that the response to this was to start using flat tops to reduce overall cell length without considering compatibility issues.

So in direct answer to your question, there are some lights which cannot use a button top, but can use a flat top. However there are many more lights which cannot use a flat top and need to use a button top.

For maximum compatibility I would choose button top cells and if purchasing a new light see if there are any issues reported in reviews regarding long cells being used.

My first choice of cell is button top.

Yeah, it would be nice if this was a little more standardized, or at least if the manufacturers were clear on which style the light would work with etc.. Not just with the length but diameter also. It would be annoying to buy a new light and battery just to get them and have them not work together. Someone a little new to 18650 lights starts looking and thinking all batteries are basically the same, has a pretty good surprise when they start doing some research on it.

Your suspicions are correct: some button-top 18650 cells do not function in some lights intended for the 18650 cell. Specifically the Eagletac 3400mah cell with the smallish button top does not contact the brass _ring_ used in the Zebralight 6330 for the plus contacts in the light. The Eagletac 3100mah cell has a wider button top and does make contact. My AW 2900mah cells with a flat plus contact function quite nicely in the Zebralight 6330.

Otherwise the Eagletac 3400mah cell is very good. Both the AW 2900mah and Eagletac 3400mah cells hold their voltage up during a high-current load better than most 18650 cells. See HKJs 18650 test report.

moldyoldy said:

Your suspicions are correct: some button-top 18650 cells do not function in some lights intended for the 18650 cell. Specifically the Eagletac 3400mah cell with the smallish button top does not contact the brass _ring_ used in the Zebralight 6330 for the plus contacts in the light. The Eagletac 3100mah cell has a wider button top and does make contact. My AW 2900mah cells with a flat plus contact function quite nicely in the Zebralight 6330.

Otherwise the Eagletac 3400mah cell is very good. Both the AW 2900mah and Eagletac 3400mah cells hold their voltage up during a high-current load better than most 18650 cells. See HKJs 18650 test report.

Click to expand...

There is no rhyme or reason. I have an ZL 600 and my EagleTac 3100s work perfectly, same with my naked Panasonic 3100s and Sanyo 2600s. However, my naked Sanyo 14500s, with similar tops, don't really work in my Xeno E03 and/or Icon Rogue 1 without some added tidbit to help make contact with those driver boards.

Remember, it's not always the positive top's shape, that is the problem. Some cells, like FastTech's protected 18650 3400s are fatter in the waist and don't fight narrow compartments.

We almost need a spreadsheet, with everybody's lights on the left and on the right, we list the cells that we actually use and which actually fit.

We can speculate until the cows come home, but until somebody drops a certain brand of cell into a certain flashlight and gets it to turn on, who knows if something will work, or not?

Chris

I have a Thrunite TN40s that will not work with button top batteries. They cause the flashlight to malfunction. Apparently they don't make proper contact so I was looking for some kind of remedy or idea of how to make them work.

I have some cheap clone 18650 lights that work with flat top cells but often I have to put them in and then turn them around or shake them as I believe some contacts in the lights are flat metal instead of a spring and the thickness of the wrapper of the cell can be a problem as thicker wrappers can put the metal flat top out of reach of the contact if it is too thick but a thinner wrapper works fine.

Zebralights are super picky. I have a ZL SC64w that will only take unprotected flat tops. It uses pogo prongs not a spring and has to have batteries of just the right size.

Many of my lights don't like trying to squeeze in the extra long Fenix 18650 with the built in USB.