AAA-P Explosion!!!

hello all,
This week end the weirdest thing happened. I was fixing something using my AAA-P, it was "on" for about 4-5 minutes, all of a sudden the light died on me. I tried to turn it "on "off" again to see what just happened. To my surprise the head was not "easilty" twist to "on" "off" positon and I had to use alot of force to twist it. As I was doing so, I heard this explosion sound inside the tube, sort of the sound you hear when you blow a small fuse. Then it became even harder to twist the head off but I finally did it. As son as the head came off smoke came out of my beloved light and my fingers turned black from some kind of powder. I tought it would be the end of my AAA-P's life cleaned the head twisted the head back on and the light came on to my surprise, but on the "moon" mode, I changed the battery and the light was as good as new, as if nothing ever happened. Can anyone expain what just happened beside the "twilight zone" stuff?
Thanks,
Ardy /ubbthreads/images/graemlins/smile.gif

haha, whoa.
did the battery leak?

Sounds like gas buildup from the bat. this has been discussed here many times. It can happen on any flashlight with a sealed bat. compartment. Gasses build up in the tube and an explosion can occur.

When you were unscrewing the head did it pop off? Did you hear any gas escaping? Probably a problem with the battery and not the AAA itself, although Id look for a short maybe?

No batterey leakage, and yes the explosion happened when I was unscrewing the head. Should we from time to time open the flashlight for the gases to escape?

Before this recent occurance, have you used the light with the same battery for any extended length run times? or even a lot of short lenght run times?

I've had that before, it went pop when I took the old battery out!

I used the light alot, actually it was still the same battery I put in when I purchased the light from ARC. Mostly used it in 5- 15 minutes increments.

I have noticed the gas build up also.

Once my AAA stayed on by mistake. When I remembered the light I found it dead. The light was out and I couldn't turn the head. I thought I had killed it, maybe the battery had exploded and leaked! I grabbed an old inner tube and pliers and started turning. I almost gave up when the head finnaly turned. When oppened past the o-ring, I heard a pop also. Inside I found a perfectly sealed dead Duracell.

Now I regularly open up all my ARC lights if they have been used, just to be one the safe side.

I'd guess the "black" that came out all over your fingers might have been decomposed O-ring material, rather than smoke -- any thought from experience? I have had some experience watching rubber turn to black powder from various causes (sunlight, chlorinated water) and wouldn't be surprised if the gas leaking from an AAA cell isn't also going to react with the O-ring.

In any event, standard advice applies, don't lick your fingers.

This is just one more example that tells us NOT to use Arc AAA (in fact, any decent light) as a "dead battery squeezer". The last few Jules of energy does not worth the scare of distorying the light.

If you "peel" an alkaline AAA or AA (or C&D, I think) you will find that the cylindrical case is + (!) If something rubs/wears through the the wrapper, you could get a direct short. Most batts don't like being shorted-out and will emit juices/gas in protest. Just a thought.

Larry

I don't think the black dust was decomposed O-ring material. I remember a similar substance resulting from an electrical experiment that exploded when I was a kid. It's amazing so many kids make it to adulthood, now that I think about it.

I still want to know if this is a design flaw or all sealed(waterproof)flashlight will accumulate this battery gas in them? In other word this is "normal"? Will it happen in my LSH-P too? Is it possible to have a small valve to emite the gas out but still keep the light waterproof? We're all waiting for the LS4 to come out, but hopefully without this problem.
Any comments anyone? Peter?
Ardy /ubbthreads/images/graemlins/smile.gif

a waterproof unit will also be somewhat air tight, also installing a pressure relief valve in any light would probably triple the end users cost and need some sophisticated valving in such a small space as a AAA light body and then it would no longer be a keychain sized light, more likely it would end up the size of an AA light

Dive lights have a small catalyst(?) bead inside that absorbs gas emitted from the cells. I don't know if the Arcs have anything like that.

No platinum pellets. Search for "explosion" in this forum. There are several documented cases of flashlights exploding, all happened to flashlights with catalyst pellets. The skinny is that catalyst are not proven to prevent explosions.

Peter

While not an Arc AAA, I've had a certain 2-AA flashlight that built up enough battery gas pressure to actually bend the polycarbonate lens almost to its breaking point. I remember picking the light up and looking at it, thinking.. 'gee I don't remember the lens being so bowed outward like that before.' When I tried to twist the head to turn it on it was very hard to turn. I had to get a rubber can opener to get enough grip to twist the end cap off and I heard a distinct "psssst" as the gasses escaped past the O ring. The lens returned to its normal flatness, but looked like it had hundreds of tiny spider cracks in it from the stress. Needless to say I replaced the lens with one from Flashlightlens.com. And I now leave the end cap loose if I'm not using the light for long periods of time or remove the batteries completely. I do remember that the batteries were not alkaline, but "heavy duty" Panasonics (like what you get with your TV remote in your new TV box.) Maybe they vent easier/more than alkalines?

Anyway, it was the first time I'd ever seen venting by batteries. Kinda neat, but a little unnerving.

- Brian

The only lights I know of that have escape valves across their line is Pelican's dive lights - I don't think that the PM6 has one, but most/all of their plastic-bodied lights do. I don't know of any metal-bodied light that has a valve.

it's never happened to me, but maybe I'm just lucky.