Hot Battery Left Me A LIttle Cautious

So i had my grandparents over and long story short i was going to give my grandad my spare Astrolux Stainless S41, and decided that a quality protected battery would be best and proceeded to place my Klarus 3600mah 18650 from my XT12GT in to the tube.

Being a reasonable new double sleeved NCR18650GA, i felt comfortable with this choice, until i stupidly wedged the negative end into the tube first with head removed (tailswitch left connected to tube) and noticed a fair bit of heat on my finger and a red hot ribbon burn through the wrapper.
i removed the battery placed it outside with little incident, but was left a little gun shy as was the grandparent.

very long story short, i tried to fit a battery into a tight non-anodised tube and paid for my ignorance forcing me to reevaluate my little knowledge about battery’s in general.

Once i removed the wrapping to investigate i noticed that a combination on the wrapping over the protection strip running the length of the battery and kapton tape cut on the sharp stainless tube and a slight jaggedly cut tab from the protection board itself, pierced the wrapped and made contact, the strip being positive the jagged piece being negative, and the rest is history.

now i wasn’t using excessive force, but i was in the wrong, but the jagged cut end of the protection cell seems to an over site thats left me feeling odd about protected cells.

thought please, and fell free to mock my stupidity.

My first post.

yeah sorry mate, have just signed up to imgur and had to work out how to use it.

My attention to detail may be considered OCD. But, to me part of the fun of getting a new light is taking it apart.
Sanding the tube ends to remove burs and edge flashing is part of it. Chamfering the edge of tail caps to allow smooth fit over Oring so not to cut. Take out driver to make sure it seats properly and has good continuity. Most important to me is to remove emitter and assure the shelf it sits on is Flat and replace with Good thermal compound. Other general mods follow.

I am not one to buy Protected cells and have removed the protection circuit on many.
Thanks for the post and sharing. Good awareness points to look for in lights and cells.
Keep battery wrap sleeves on hand and replace them with any sign of damage. I like the clear or translucent colors so I can write on the metal shell the maker codes and not worry about them wiping off after a re-wrap.

events like this is why i do not use protected cells.
any i have gotten have been stripped and resleeved.
i figured out many years ago that a problem with the protection stuff had more potential for disaster than any benefit it offered.

Is it Klarus brand 3600mAh? That is really unacceptable if they left the sharp tab wrapped inside. It will pierce through any time.


I think there is a lot of stigma surrounding the term “unprotected” so, a lot of folks opt for protected variants.
However, the battery chemistry in an unprotected cell is inherently safer than that used in protected cells.
Unprotected cells are far more reliable as well, as there is no IC or connections to fail. YMMV… :+1:

Disagree with the comment on chemistry - might have been the case a few years ago but not now. No difference in chemistry between my protected Sanyo GAs and my unprotected Sanyo GAs. Likewise my unprotected Keeppower “IMR” 26650 5200mAh seems to be the same battery inside the wrap as my protected “not branded as IMR” Keeppower 26650 5200mAh. (Pretty sure they are both INR anyway).

Yeah, should have clarified a bit there… :person_facepalming:
I haven’t been keeping up on the bleeding edge of battery tech, but AFAIK, IMR chem. is still the safest around (best at mitigating heat). For single-cell, high-amp flashlights (which are the norm around here), they are hard to beat, and are compulsory in many cases. Trying to use a protected cell in a high(er)-amp light can be an exercise in frustration/futility, if the cell’s protection circuit trip-point is lower than the lights power demand on hi.

A well-made/designed high-drain IMR battery doesn’t need a protection circuit IMO (unless it’s being used in a multi-cell pack in series). That’s why you really don’t see many protected IMR cells around, unless they are re-wraps. Individual cell protection against over-charge/discharge/current definitely has it’s place though. However, for single-cell applications (or multi-cell configurations running in parallel) it’s really a non-issue IMO, especially for most savvy users here. In addition, most lights out there these days have LVP and reverse-polarity built in already, which removes the need for such protections in the battery itself. Granted, if I were gifting a light to someone who wasn’t in the know, I would most likely include protected cells.

Regarding your Sanyo GA cells, I believe they are NCR chem, which is a newer “hybrid” tech if I am not mistaken. I think that is probably leagues better than the older INR tech, but still not quite as safe as an IMR cell at higher discharge rates (again, heat being the enemy). I doubt you will see many (if any) NCR cells that are rated for a continuous drain of more than 10A or so, whereas several IMR cells are rated at/above 20A. So, your GAs are likely a lot safer without a protection IC than an older ICR cell, but not quite as safe as an IMR.

Also, if your last sentence is true, it illustrates why I don’t bother with re-wraps any longer! YMMV… :beer: