CMG Ultra-G, explosion

I got my CMG Ultra-G out of the car a little while ago to show to one of my coworkers. For some reason, I couldn't turn the head to make it come on. So we got the pliers out & I proceded to unscrew the head with some difficulty. Well as soon as the threads cleared the head exploded off of the body with a loud pop, similar to a champain bottle. I think it may have been 100 lbs. or more of pressure on it. The battery had leaked into the body and apparently somehow built up a considerable pressure in there. Fortunately, no one was hurt.
This was a brand name alkaline AA cell. I'm not sure what caused this. I leave other flashlights in my car without having to worry about the batteries leaking although it sometimes gets pretty hot in there. It wasn't hot in there at 9AM with the windows craked, but there is no way to tell how long this flashlight may have been that way. It had been in there about 10 days. This was a fresh battery (best before 1-2007, so not real new). Any ideas?

Lithium?

Nevermind. You said alkaline.

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RussH said:
...It wasn't hot in there at 9AM with the windows craked, but there is no way to tell how long this flashlight may have been that way. It had been in there about 10 days...

[/ QUOTE ]It could have ruptured days before. The pressure build up would have stayed constant, or even increased over a day or two. At least you know the light has a good, water-tight seal! /ubbthreads/images/graemlins/wink.gif Your story is a another reason why I feel lithium powered lights are better for keeping in a car. From what I've read on here, lithium seems much more stable in temperature extremes.

My Ultra G is the only light that I've had a problem with pressure. I relieve mine on a regular basis, so it's only been really tight once. I've not had a battery leak in mine yet.

If it's a major battery manufacturer, they will repair the light or pay for its replacement, including shipping charges and the cost of batteries. It'll cost you less than $2.00 WITH INSURANCE to send it back.

Both Duracells and Energizers have caused damage for me. Both have paid to take care of the damage.

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kitelights said:
I've not had a battery leak in mine yet....

...Both Duracells and Energizers have caused damage for me. Both have paid to take care of the damage....


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Yikes, I just put in an order for an Ultra G from County Comm... What with the weather over here going at around 30-35 C everyday, I'm beginning to wonder if I should've gotten it or not...

Hmm... Maybe I should consider drilling a hole in the body? /ubbthreads/images/graemlins/twakfl.gif

I think I'll email Energizer & let them know about this. The alkaline paste that has leaked into the body of the flashlight does not seem to have started corroding the aluminum. Non of it got on the head. It appears to be the seam at the bottom of the battery that has leaked.

I would think it would take no more than a couple of minutes to clean this out with a mild acid to insure it's neutralized. That would be less trouble than mailing it. It might be interesting to see if they can find a CMG Ultra-G to replace mine. I wonder if they have someone that's familiar with the CMGs or this forum.

Henceforth I'll use a Lithium AA in this one (or it's replacement if I go that route). I have two, and the one I normally leave in the car (it's been in there for months) hasn't had any problem. It has a Lithium AA "photo" battery in it. This one is the one I normally carry and use. I changed batteries in it after a camping trip & left it in the car....

Stanley, if it really concerns you, I think the lithium AA (1.6v photo cell) should do OK. You might try simply removing the O-ring if you want to make sure it's not air tight. And/or maybe file a notch along the threads. The O-ring could be replaced if you need to waterproof it again. I personally think the tightness of the head is warning enough. I'll take a lesson from Kitelites & check it more frequently.
RussH

It's possible that a product manufactured in bulk for pennies and sold for a dollar may have undetectable flaws and fail in use. I wouldn't blame the light.

Would one of the dive lights with a hydrogen absorbing pellet have survived this?

RussH, this reminded me of a recent thread here on the buildup of Nitrogen gas in the water and air tight lights.

HELP, My PrincetonTec Surge just exploded; I'm hit

Where I live in South Texas the heat buildup in a car is substantial. I've kept a SL Twin-Task 2 123A Lithium light in the glovebox all summer and haven't had a problem. I don't know how much of it is due to the Lithiums or the ability of the SL TT to vent gas.

I've heard of what happened with your CMG Ultra-G happening with another similar light. I just changed out the alkaline in my CMG Infi Ultra with a Lithium, just to be on the safe side.

BC

Yup, thanks for the advice Russ, and looks like lithiums are the order of the day... Just wondering while we're on the topic of lithiums (and I dont seem to have gotten a reply in the batts thread yet), but do lithiums hold up as well in heat as well as in cold?

Hey All,
My father-in-law brought his Ultra up here this summer and could not get it to turn very easy. I cranked it and cranked it until finally POP off came the top. No corrosion or anything, but just a build up of pressure. The battery was totally dead too. I believe it is more of a battery gas reaction than a termperature thing as his was NOT in a hot place. The corrosion part would just add to the gas buildup. Best bet is OPEN your Infinity once a month or so or when you feel it starting to grab tighter than normal.

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BC0311 said:
RussH, this reminded me of a recent thread here on the buildup of Nitrogen gas in the water and air tight lights.


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Actually, you meant to say Hydrogen gas, which is explosive (Nitrogen is inert).

I wonder if the flashlight turned itself on and ran the battery down when it heated up in the car. If batteries expand more with temperature than aluminum does and if you twisted the head just enough to turn it off before putting it in the car, then this could happen.

Something similar happens to my plastic Tektite flashlights. The plastic expands and contracts much more than metal does. If I put this flashlight in the car in the winter it will come on when it gets cold if I don't unscrew the head at least 1/2 turn or more.

To me, the most attractive things about this flashlight are the fact that it's waterproof and that it runs on a regular AA batt. But the ways to keep it from exploding are to make it not waterproof and to use a lithium batt. That sucks.

Stanley, lithiums are even better in heat than in cold. The self discharge rate is something like 1% per year in lithium batteries compared to 1-3% per MONTH for most other batteries at "normal" temperatures. You can do a google search & get some hard numbers for specific batteries or temperature extremes.

I used to swap out my car flashlight batteries about once a month in the summer just to be sure they would work when I needed them. Lithiums I don't bother with. It doesn't get cold enough here (MS) to matter what I use in the winter, but lithiums maintain a higher voltage. Voltage is a bit low on alkalines below freezing. You can simply warm them up using body heat if need be, tho.

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LEDmodMan said:
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BC0311 said:
RussH, this reminded me of a recent thread here on the buildup of Nitrogen gas in the water and air tight lights.


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Actually, you meant to say Hydrogen gas, which is explosive (Nitrogen is inert).

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You are absolutely correct! Thank you. I am such an ape. /ubbthreads/images/graemlins/thinking.gif

BC

Eluminator, I considered the possibility that expansion from heat may have caused the battery to make contact and run the battery down. It doesn't seem likely but I can't entirely rule that out. I usually turn it at least a half turn to make sure it is off and stays that way.

Kevin, I am sure I had this light open only about 10 days ago. I feel pretty sure the battery failed for whatever reason. Still, I can check it more frequently without any real trouble.

I believe my father-in-laws also was not loose enough and somehow turned itself on too. Hydrogen gas is a normal byproduct of a heavy discharging battery. It is possible that under the load all the way to dead that some gas built up. Further, when the battery hit zero, it managed to leak acid. You actually had two seperate things happen at the same time. I have seen both happen independent of each other too. You will normally find that good batteries do not leak, but dead ones will quite often.

Same thing happened to my Arc AAA. I use it almost everyday and one day I tried to turn it on and it would barely budge. Finally got it unscrewed and rec'd a nice little POP! and a freshly exploded battery inside.

Cleaned out the inside and it hasn't happened since. I think it was just a defective battery.