Why did this happen?

[OUScubaGrad07]

I'm at a loss! This weekend, i went diving with a couple of buddies. We first made a brief dive (20 minutes TDT) that went to 92ft. I was using one of the 6aa Ikelights as my dive light. We surfaced and picked up our other buddy and made a dive to 74 ft ...TDT 18 minutes (both times dives were short because buddies were way too cold. The temp at 92 ft was about 52 degrees and 55 at 74 ft. Surface temp was about 84 degrees. After our safety stop, while ascending to the surface, at about 10 ft, there was a loud bang sound underwater, as the light exploded...the top of the light (which houses the actual light and the switch), had blown apart from the battery housing below sending all of my batteries to the bottom of the lake....the apparatus that holds them together was still intact and in the closed position.

So my question is WHAT THE HELL?

 

[gcbryan]

Hydrogen go bang,bang.

Somehow some water got into the light. I had one that waited until I got to the parking lot after I flooded the light. When I unscrewed the top there was a loud bang with internal parts shooting accross the parking lot.

Some lights have a little metal catalyst that prevents this in the case of flooding as long as you replace the catalyst each time.

 

[OUScubaGrad07]

How does water getting into the light cause it to explode? I'm still confused...anyone?

 

[gcbryan]

Salt water + battery = hydrogen apparently

 

[Ed Palma]

Electrolysis of water. Not just Hydrogen, but oxygen too Isn't this the reason why some llights (like pelican lights) have a pressure relief valve?

 

[Tigerman]

Sounds like a fun experiment for when I want a new light.. Or maybe not..

 

[do it easy]

Sounds like a fun experiment for when I want a new light.. Or maybe not..

Better wait until your buddy gets a new light and then just borrow it from him

 

[Marek K]

I agree it was hydrogen... but I don't think it exploded.

As I understand, batteries naturally give off hydrogen gas when they're working. And rechargeable batteries apparently do it more. (Were these rechargeable?)

Just re-read your post. This was an Ikelite PCa, right? That's happened to me with a PCa, too, with rechargeable batteries. Fortunately it was in my BC pocket right after I'd surfaced; I heard a *pop*, and everything was in pieces... but I was able to save the light... though the locking lugs got damaged a bit.

Batteries were fine too; hadn't gotten wet except I think from contact with the wet BC pocket.

The PCa, great light thought it is, has I think a very poor system to secure the light head -- a latch, rather than screwing on. What apparently happens is that the hydrogen pressure builds up; it's fine at depth, but when you're ascending the decreasing ambient pressure can cause the light head to pop off.

Same thing's happened to at least another SB member, while he was ascending with a PCa -- there's a definite pattern here.

After that, I started switching on the PCa only when needed... or carried it as a nighttime back-up.

I've now gotten an Underwater Kinetics Mini Q40 eLED. Only uses four AA batteries, seems about as bright (though produces different color light -- bluish -- and a bit more diffuse), and with the LED should last longer per charge. Plus the bulb won't shatter. Plus it's got a screw-together case.

--Marek

 

[Tigerman]

Would Underwater Kinetics be the full name for "UK"? If so, I have the very same light. Also have the UK C-8..

 

[Marek K]

Would Underwater Kinetics be the full name for "UK"?

Yup.

If so, I have the very same light.

How do you like it? I'm very happy with mine.