Ni-Zn gas venting


Newly Enlightened
Mar 10, 2011
I carry a 4sevens Quark aa2 warm tint for work as an inspection/ work light as a mechanic. Now I usually only use it for a few seconds at a time, a hundred times a day.
I recently purchase a Powergenix charger and 4 aa batteries. They have been working fine, untill this occasion.

I was working late one night, and was using my Quark on a nite-ize headband as a headlight, on max power, for a couple of hours, untill it started dimming. I had never run it this long before. I went to push the button to turn it off, and had some trouble (light still on my head) I thought the switch was broken, jammed, so I too the light off my head and immediately noticed the switch boot swollen to huge size. So much pressure that pushing the button was difficult. I took a couple of pictures on my camera phone (I don't know how to post them here) and unscrewed the tailcap to let the pressure out. Puff! Now th weirdest part was that after I closed the light up, without even running it again, over the next fifteen minutes it built up pressure again, not quite as bad, but still visibly swelled the tailcap boot.

It has never happened since (i have never run it that long again) But I thought I should post it here.


Newly Enlightened
Mar 17, 2011
The Quark AA2 has a voltage range: 0.9V ~ 4.2V. It will be running even with 1 cell empty. This cause the empty NiZN cell to vent from reverse polarity. The Quark driver maybe drawing a very very low current for last level memory which would explain the venting in off mode.

I would identify the weak vented cell with a DMM and throw it out. It is dangerous to use the vented cell again in the 2xAA flashlight especially when working near engine and hot exhaust.

Check out the
Eneloop gas venting? thread.

I hope you post those photos of the puffy boot.

Just upload the photo to which does not require registration. Then use the "Insert Image" button on the editing tool bar to add the image link. You should start a thread in the Practice-Posting and try it out. Once you get a hang of it, it will be very quick and easy to post images.


Newly Enlightened
Sep 3, 2010
This really sucks, I love my NiZn cells but my g/f is a very casual "throw whatever batteries look the same or close" into our gadgets type. Anyone know of a good charger for these that will level them out? I have the Powergenix black, and white version of the charger (white one is FAR heavier) and both are supposedly 2 channel but will trickle charge by design.


Newly Enlightened
Aug 24, 2010
Wow, I'd love to see those pictures of your switch boot. I guess it makes sense that it would inflate instead of, well, pass the gas, given the water resistance of the Quark line


Newly Enlightened
Nov 25, 2011
Similar venting occurred with my EagleTac P20A2 Mark II:

Turned the light on (Low) and the light fell over when I tried to put it on it's tail stand. It was then I realized the boot over the switch had inflated just enough to keep it from standing. Opening the light I noticed one of the batteries had a mark you can see in the images (Sorry I couldn't get closer). You can find the mark over the "PL" in "APPLICATIONS". When I think about it, it was there when I opened the package (Bought these Powergenix less then a week ago).

Could this be where it's venting from? These shouldn't be used again...correct?

It's a shame about the NIZNs, they made the light significantly brighter!! But dependability is more important.


Apr 10, 2011
Same thing happened with my Fenix TK45 using newly bought and freshly charged Sanyo Eneloops. I was running it on medium, but I noticed the puffed switches quickly, so nothing bad happened.

It never happened since then.

iron potato

Aug 1, 2011
Well, same thing happened with my Ni-Zn in Fenix TK41, while ago, I on it on High mode after I came back from work,

It ran for few hours & started to dim... so I assumed it was near depletion.

Switch it off & once I opened the tailcap, I heard a pssshhh sound coming out, quickly check with DMM on each cells & one die with 0.7v.

While the rest were approx. 1.3-1.4v, now I just use these Ni-Zn cell in clock & low power single cell flashlight, while I switch to Eneloop XX for my TK41 with great results ~

Yea I agreed with mindthegap that its quite a shame about Ni-Zn ~

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