Tonight I just took the battery out of my Roche F12 and noticed that the positive contact of the 18650 battery was crushed. I am using an UNprotected Panasonic NCR18650B.
Will this be a problem? I know that the battery will probably be incompatible with more flashlights than it was before as a flat-top, but is it it still safe to use?
Convoy S3 will have the same issue if you dont pay attention. Basically you should have been able to tell something was wrong by how much force you needed to screw the tailcap on. But thats all water under the bridge, theres quite the easy fix for this tho; Either remove that spring from the board and replace it with a more forgiving spring or a short solid post (as long as the positive contact is slightly higher than that amc7135 around it you’re all good) or you can cut the current spring down by about half but do file it down after or put some solder on it or the rough cut will damage the cells. The 105c spring is just too tall and stiff when used in conjunction with short-ish body lights.
Wow, that’s quite a design f… foul up there… 
Thanks for the responses. I think I’ll leave everything as is for now, as long as I’m using this particular battery for this torch, seeing as it’s already crushed. Unless there is some danger to it.
I have lots of squashed positive contacts on my cells. It doesn’t hurt them. It’s just a contact plate being held in place by the wrapper. I just keep the same cell in my F12. You could always go with a shorter unprotected flattop, but I wouldn’t worry about it.
All of the last-line safety features are located under there. PTC, CID, pressure valve. Crush the positive in enough and they may just become compromised.
You should not just leave this light & battery the way it is as if everything is fine.
As RepProdigious said, you can cut the driver spring & file the sharp cut edge. Alternatively a plastic disk or two (cut from soda bottle cap) with a hole for the spring could prevent it from pressing in enough to crush. Also I recommended you switch to LiMn or quality protected li-ions (mtnelectronics protected, keeppower etc)
The battery pictured is already an unprotected bare NCR18650B “flat top”. There is a bit of space under the flat top contact to allow for the vents but there is no extra after factory button top mounted & shrink wrapped over it.
In the end, if you’re going to use a Panasonic 18650B in a Roche F12., there’s nothing to be done. Those cells are long. The spring isn’t the culprit. You can’t do anything about the driver spring, since it barely clears the 7235 chips on the board. Try Sanyo 2600 unprotected flattops.
Here’s my Roche F12 triple and 18650B that I carry every day.
I have to disagree. I've seen some nanjg 105c springs that are shorter then others but all are higher then needed & allow battery tops to be crushed when room is tight.
Roche’s just don’t like long or protected cells. The only reason I use a Panasonic in mine is because the end was already crushed from other lights, and I need the run time. They have really flimsy end caps. When the driver spring is compressed, the cell is still crushing down on the chips. Not a good thing. My tail spring compresses so flat that the bottom of the cell bridges the gap to the battery tube, bypassing the switch, keeping the light on. I stuck on one of those clear reflector isolator discs around the spring to prevent this. I have a few Roche’s, and they are all tricky with cells. You can either use shorter unprotected cells, or keep the Panasonic since it’s already “custom” crushed. Mine is going to live out its days in this light.
Yes.
You can get an extra couple mm by replacing the stock Nanjg 105c spring with a flat brass button (Mountain Electronics sells them), or a couple pieces of copper sheet.
The Roche F12s have that flaw where the battery tube needs to be a couple more millimeters longer to work with the longer 18650s. I shortened the springs on the driver and tail cap on my F12, and made an aluminum spacer to go in the head to lengthen it to be able to use either protected or unprotected cells in it.