Exploding lithium battery. Beware of lithium batteries in diving lights!

[black_sea]

Been buying cheapo chinese lights online to test for possible budget backups for open water. On its first dive, one of the dealextreme 18650 battery powered lights took on water at 18 meters, unnoticed by me. It kept shining, and I could not see water when I looked at the glass. After the dive, unaware of any problems, I rinsed the light, to screw it apart for service when I got back home.

When I god back, it was hard to unscrew it, so having some bad experience in the past, decided to treat it as flooded.

I got a plumbers wrench, eye protection, gloves, thick work jacket and went to my industrial sink, and attempted to unscrew the light, making sure to point any openings away from me. The back of the light flew away with an explosive pop as the gases were coming out of the body. It left a dent in the steel sink.

There was some corrosive fluid everywhere and it was lucky to have taken the necessary precautions. The light had severely corroded in the few hours that had passed, Could have gone way sour if the liquid got on the skin or eyes.

Lessons learned - how I am going to operate in the future

Do not use lithium batteries in lights that have not been pressure tested personally.

Take all lights to maximum operating depth, without battery, to test for leak (somehow real life tests sometimes produce different results from pressure pot testing)

Stick to non-rechargeable batteries in backup lights

Use a charging box outside-the-house to charge batteries and not leave chargers unattended

Treat all lights as flooded unless proven otherwise. Disassemble with same rules as for hazmat and explosive.

[Hatul]

I don't see how you can generalize from one experience with one light and one battery to all lights with Li-ion batteries. You can get a bad light and a bad battery in any brand.

I have four lights powered by the 18650 batteries and never had the problem. Even UK makes a light powered by this battery.

[lucca brassi]

Can you post accurate brand , type , (production time )of your battery ?

[wedivebc]

Actually anydive light will build up pressure when flooded due to the generation of hydrogen and oxygen gas from electrolisis. The battery is just a power sourse Lithium has nothing to do with the reaction.

[PfcAJ]

Some lithium batteries are more stable than others. You can't really paint them all with the same wide brush.

I wonder how much you've spent on cheap lights when you could just get a nice one and be done with it. Seems a lil backwards to me.

[black_sea]

I wonder how much you've spent on cheap lights when you could just get a nice one and be done with it. Seems a lil backwards to me.

In the end, everything fails. I have lots of expensive lights that burned, flooded, etc. I do not quite see your comment as productive. And who are you, the queen of england to make generalizations like that?


---------- Post added at 12:51 PM ---------- Previous post was at 12:49 PM ----------

Can you post accurate brand , type , (production time )of your battery ?

18650 2400mAh Ultrafilre. Not sure about serial and date, thing is a brown turd now.

[Jax]

Subscribed.

[Hatul]

It looks like your light flooded probably from a bad or poorly seated O ring or dirt on the O ring. It can happen with any light or any underwater housing. Can I ask you how many O rings the light had?

You should be able to send the light in for exchange.

Before closing the light I wipe my O rings with lint-free eyeglass cleaner (wet paper or cloth) and lately I don't even lube the ring as most of my diving is shore diving with lots of beach sand and I find the grease just attracts the sand.

[MikeRD03]

A chinese Light with chinese Lithium cells (ultrafire) - probably not the best combination. It´s not first light exploded even without water. Have a look at the Candle Power Forum where you can find some of these incidents. And water contact under pressure will make things not better, I guess.

You are lucky, blac_sea, the the cells did not suffer a thermal runaway under these conditions, cause that would have lead to a housing explosion even under water pressure.
As I said, the Lithium-Cobalt chemistry is not first choice for diving lights and it never will be - regardless of the cell quality. There ever will be a compromise between safety and capacity and Lithium-Cobat is on the capacity side. So I was not surprised at all reading your report..

bye,
Mike

[Hatul]

As Dave pointed out, electrolysis is the likely culprit once the light leaked. The current passes through the salt water and breaks the water molecule into oxygen and hydrogen. The underlying problem is that the light leaked and the likely problem is with an O ring seal.