Did a dunk-test a bit differently

LED Flashlights – General Info
1

Ok, you may laugh and I admit this was done partially by accident...

I was just discharging my 18650´s for summer storaging down to 3.80V or so.

Burned my hands once or twice with 980L and thought, I´ll cool them down with water once in a while.

I took a plastic cup with 3" of water. Dunked C8, 980L and RC-601 in there tailcap first.

Had some thoughts of them taking water but then again, thought about seeing what happens.

Lights cooled down nicely.

After 15min of continuous run, opened them up.

All soaked (no surprise actually, they were all HOT!).

980L was soaked so bad, it had water all the way up to the driver! At this point, I was on a bit of a rush to take all up and apart to dry them, so sorry, no pics...

All lights were in the puddle tail end first about 3" and all were soaked pretty well.

Least flooded one was the plain basic C8, Romisen did also pretty well. Reason may be, that they were running a bit cooler.

Conclusions:

-When dunking, don´t dunk a warm light into cold water (duhh).

-If dunked accidentally, pick it up instantly.

-Think about it: Your lowest output light may actually keep the water out better than your hotrods!

2

Hmm, no comments, I think this was a very obvious thing to happen to everyone else than me :D

3

Did any of the lights have IPX ratings?

4

Lithium is a highly reactive element when exposed to water. The +B vents on cells are supposed to be well sealed against water intrusion, but I wouldn't chance it... at least not without thoroughly going over the light to make sure it can safely seal out water. I have 2-3 lights that are modded to make them shallow water submersible. I add O-ring gaskets and teflon tape to the threads.

http://www.youtube.com/watch?v=QoXaArRHfAw

This L2m is my favorite. I have 3 O-rings and plumbers tape to seal out where the bezel screws onto the body tube. The updated stainless trim bezel pushes harder against the front lens to compress the front gasket more securely than the plastic surefire trim ring. The tailcap has double O-rings where it threads onto the body. I also have a SF-6P with similar water treatment.

5

[quote=BetweenRides]

Did any of the lights have IPX ratings?

[/quote

That would be my first question too. Also, and please forgive my ignorance, but what is the extra significance here of the fact that the lights were submerged while hot as opposed to cool? In what way would the heat make them less H20 proof?

6

[quote=Lensman]

[quote=BetweenRides]

Did any of the lights have IPX ratings?

[/quote

That would be my first question too. Also, and please forgive my ignorance, but what is the extra significance here of the fact that the lights were submerged while hot as opposed to cool? In what way would the heat make them less H20 proof?

[/quote]

The temperature of the light is insignificant (for all practical purposes). A light that leaks when cold is also going to leak when warmed up, and vise-versa. The thermal expansion of materials like brass, Aluminum, silicone and neoprene rubber is very little at the temperatures we are talking about with LED flashlights.

7

For kramer5150:

If you need to make light watertight, I would take a special care on the tail rubber boot.

All these had the leak going through tailboot and IMO it was pretty obvious since all clicky components were thoroughly soaked up.

I might note, that all lights were functioning before, during and after the test.

About hot and cold:

When light gets hot (and I mean HOT, these were run on high on table for tens of minutes, too hot to touch) it AFAIK raises the body's internal air pressure.

Air leaks out if not properly sealed.

I believe in this case, air leaked out to lower the internal pressure and after the dip, they cooled down so much the vacuum sucked the water in.

There is absolutely no way for example 980L to suck that amount of water without vacuum. Water IN flashlight was Higher than the water surface itself.

Sorry, I am not aware if any of these have any REAL WORLD IP-ratings.

I have tested them by dipping to water, naturally with no problem. Never before like this.

8

Yes... I forgot to mention this as an area of concern too. I take apart the switch pill/guts and make sure there is a clamping-force that is exerted on the switch boot trim, to effectively seal out water. I spread a very thin layer of plumbers O-ring grease around the switch boot perimeter where it engages against the tailcap. Its a layer of soft greased silicone that compresses against the tailcap when the pill-ring is tightened down. That way theres minimal chance for water-leak at this area. This part of the light is critical because there is no redundant backup / barrier past that switch-boot.

I also carefully inspect the boot too. I remove it and hold it up to a desk lamp, I look through it and pull / stretch it to make sure there are no holes, tears or thin spots in the silicone that could rupture.

Wow thats a LOT of water in there. Definitely a vacuum you'e got going on there as it cools.

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I see. Thanks for explaining; I hadn't considered the vacuum aspect.

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I should have mentioned earlier, that my lights were almost stock.

Only O-rings were lubed with NyoGel, nothing extra done to prevent leaks.

All parts were naturally tightened.

Kramer, if any time you make tests with those enhanced lights of yours and especially dipping a hot light, please let me know how they perform!