Gas build up in my EagleTAC P20 A2

For the past 2 weeks Ive been using my ET P20 A2 with green LED as an area light bouncing a beautiful 532nm green beam on my wall and ceiling, using eneloops has been great until today. A little while ago the light fell over, no big deal I thought I must have bumped my desk, then I felt the tail cap and a noticable buldge. at that point I closed my eyes held light parrallel to my body and unscrewed the tail cap and the pressure was removed. then 10 min later it happened again, then a third time! I took out the 2 eneloops and put them back in the charger and replaced tham with 2 other eneloops. Eneloops are supposedly the best in class for rechargables and ET is a quailty light so I am confused about this. any idea what causes this potentially dangerous gas build up inside the P20 A2?

thanks!

Never heard of that with Eneloops. Very strange. I hope someone can provide some insight on this one. As a side note, you might get some good answers sticking this in the batteries sub-forum too.

Thanks! I put in another set of eneloops since my earlier posting and all is well again. I dont understand this either presumably it could be a battery issue as opposed to LED light issue, yet the LED light had the issue.

I'd pitch the two Eneloop cells associated with the pressure buildup. One or both of them are venting for some reason. Is the light getting unusually hot?

BVH said:

I'd pitch the two Eneloop cells associated with the pressure buildup. One or both of them are venting for some reason. Is the light getting unusually hot?

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The light did not feel hot. I appreciate this info because those 2 cells have been recharged in a couple hours, think I will discard the cells. really hate to throw an eneloop away. I had just bought a few more of these. No way to know where exactly this suspect eneloop was bought. really sad to toss an eneloop :-((. An exploding end cap is far worse than tossing a $3 cell.

I got the same problem with my Fenix LD20...and all these while i couldnt confirm if it is the battery (also eneloop) problem or due to the turbo mode. Before the gas build-up and expanding tail cap, everytime i have the light on turbo mode i can hear a faint hissing sound.

Can anyone confirm that it is indeed a battery problem. Eneloop's here costs $4.50 instead of $3..not much, but still.....sigh.

Nope, this is not a problem.

I've read several sources (don't have time to look them up for you, but you can do the research) that eneloops (and maybe others?) can give off a gas under some operating conditions.

I've run 4 x eneloops in serial, powering a custom 3.1 Amp XM-L flashlight, and they will periodically vent some gas. They don't always do so, but often do when running at full power. I rotate these 4 with other "batches of 4", and all batches seem to vent a little gas at times.

The batteries have that have vented have been used many times, without any issues or seeming loss of power.

From my experience, I say keep using them ... or if you're bothered by the bulging tailcap pushing the flashlight over, perhaps try another brand of rechargeables, or don't run your flashlight on "high" for too long at a time.

All the best,
d337944

I experienced the same already with some Panasonic Infinium cells...

Normally nobody would notice that phenomemon, the real problem is the watertightness of the lights, gaz the is emitted can't leave the tube. If you don't need it to be sealed, you may make a little hole in the rubber cap and the gaz problem will be solved.

I have never had this happen with my eneloops. Strange that this happened. My brightest light is only 230 lumens though.

Thanks for that info. I was running the light on level 2, not high. other eneloops in same light no problem

I had this happen using Duracell alkaline batteries in a LD20 Fenix. I usually use lithium primaries with no problem but had to use the alkalines in an emergancy.
I wasn't using it on high to conserve the batteries. I have duraloops and never had this issue with them.