Hey
@akatsuki:
This thread hasn't advanced much, so let me ask a couple of things.
First, I want to clarify that I didn't mean to impune the quality of your light specifically. I know zero about that brand, but it may well be a great light, and it wasn't my intent to suggest otherwise; only that popularity is not an indicator of quality - either good or bad. Plenty of crummy things are 'popular', and that is sometimes based largely on price (or 'group-think'). Sorry if my comments implied that I was knocking your light specifically. I don't even know enough about the light (or its cost) to do that, .
I assumed since you use the term 'outie', this implied that the cell was born with a protrusion (it was not flat), thus my assumption it was a standard 'button-top'. You should clarify that. I can't tell for sure by looking at it now, post-damage. If so, I would likely assume that if anything, that would add some additional strength to the end (along with overall length) of the cell, and that could also be a big factor if the light was designed with insufficient length tolerance; however whatever it started with, there may be an issue / factor in play which might make that strength less relevant. It would, however be relevant in that it would also make the cell longer, and overall length may in fact be part (or all of) the problem; thus my question of what length range the light is designed for &/or what type of cell the manufacturer recommends.
If the manufacturer provides proper ANSI FL1 specs for their product (which
is an indicator of manufacturer quality), that standard requires that all spec measurements be made using the specific recommended &/or provided (if it came with one) cell, and that cell info is relevant here. That can be informative regarding this, and the info would be noted together with the provided FL1 specifications (by requirement). If you know the specific cell, you can find out its length. If not, either way, this begs the question of whether or not this is a type of cell that is provided with the light, which obviously should itself imply compatibility, so you should clarify whether or not the cell(s) are provided by &/or recommended by the light manufacturer. It's OK if they're not, but the answer matters in this case.
Some lights are designed to use shorter cells in general, such as the type designed for spot-welding bus bars on them for constructing battery packs, which is a fundamentally different application. The ends of those 'bare/flat top' cells may be more prone to such physical damage than those with the button disk added to a bare cell end. Again, however, if the light is specifically designed for such shorter cells, it may not be designed to accept much deviation from the 'nominal' length of the cell type (such as 50mm for an 18650). I would consider that a design limitation (although I'll stop short of calling it a 'defect') in the real world of flashlights, where cell lengths
do commonly vary, and also many of us also want to use 'protected' cells, which also adds to that nominal length. It may just be a rather inflexible design. What is the cell length (or specific type) stated / recommended by its manufacturer? Is the one in the photo a 'protected' cell? I can't determine that by looking at it either, and does the manufacturer recommend that, or is that not stated either? Many manufacturers do recommend that. That info would provide another clue.
It was asked whether your light is stock or has been modified, but since you have the same issue with multiple lights from that manufacturer, that is not likely a factor. I would think it's unlikely that they are
all 'modified'. If it is occurring with multiple lights, unless they are of the same model, that would also imply that if the issue could be a bad design, rather than a unit / sample-specific issue (just one defective light), which is a critical distinction. Are those several lights of the same model, or different models? If they are different models, but using the same cell type, that would perhaps lead one to look more at the cell than the light for root cause. Since it involves multiple lights, that leads to the obvious question of whether you've been using that particular type of cell in each case, or more than one type of cell, so you should clarify that as well.
Addressing those various questions I've posed will greatly assist others in helping you diagnose this problem to root cause. If anyone is to provide a valid opinion regarding root cause, they will require more information than is in your original post. I think the ball is in your court.
