Liquid cooled XM-L Eveready 2D sleeper

I bought two Eveready 1D led lights for $3.60 at the nearest drugstore. These are almost identical to a 2D incandescent light I have had for maybe 20 years, so, except for the front and now the switch, they look like old cheapy 2D incandescent lights. They also still look much like the super budget flashlights I bought. What the manufacturer (Eveready is the brand but probably not the manufacturer) did to convert the lights was replace the bulb with a 1.5 V led dropin and widen ridges to hold the spring in place to hold a single D cell. They came with one Super Heavy Duty D size dry cell each.

I have discussed plans in the Fulton Angle-Head Military Flashlight mods? thread, but since I am not using an angle head case, I am starting a new thread now that I am progressing on the project.

So far I have cut away the ridges to take 2 D cells again, soldered a wire to the spring, replaced the switch and epoxied the pill with emitter and driver from my worst $10 XM-L light in a hole I cut in the reflector.
The critical step is in progress as the silicone glue dries between the window (lens) and the reflector, which is now full of 91% isopropyl rubbing alcohol. The big question is how the alcohol is going to react with other components, including the silicone.
Since this is only a 2D cell light, I figure that it doesn’t need the liquid to fill the whole light. It still has the more or less original aluminum pill and the alcohol will transfer the heat to the thin plastic head and window. The liquid should allow me to use a high powered led in this plastic case for more than the brief time it takes the pill to heat up. A smaller led would do about as well, but the XM-L is efficient and available. The large diameter reflector gives a small spot, in short tests, but it is not deep so most of the light goes into the spill, so a smaller size led would not improve the throw. This reflector was designed for an incandescent bulb and therefore is shallow, that is it has a long focal length relative to its size. The XM-L (with dome in tact) illuminates only the rim of the reflector with yellowish light, but the spill is great. On first try it only flashed with the two dry cells, but the next time it worked so I think it will be fine with two alkalines.

Here it is with the silicone curing. There is a bubble, I later found there was a leak through the driver.

I have the switch connected and have tried it out with the Super Heavy Duty batteries. It is not very bright on these, and I am 5500 miles away so it will be three weeks before I can try it with the alkalines. The spot is small and yellow, due to the long focal length. This also makes more spill than throw. Up to the time I left the alcohol had not caused any problems. For a thrower I will need to either turn the led backwards and move it away from the reflector, which should still cool well, or else add a secondary reflector.

I will watch this with interest. Isopropyl alcohol is flammable and will boiled at 82.5 °C so do be careful.

Alcohol or ANY other flammable liquid is absolutely the WRONG thing to use!

Oh, and alcohol flames have the lovely property of being rather invisible in lighted areas… you don’t know you are on fire until it is way too late…

transformer oil springs to my mind.

The cheapo solution would be to cut open an old car’s ignition coil - but, beware, as it might still contain polychlorinated biphenyls.

the plastic burning will also be quite visible. interesting idea. I had always thought a heatsink with heat tubes going down the battery tube would be a good idea

Interesting choice to put it in a plastic host.

then sealed in an airtight tube combined with something that inherently generates a lot of heat much less potential for shorting. I can’t think of something right now with less common sense. :open_mouth:

Sorry but I have to be real honest here.

Best ignition cap for this would be dedomed XM-L :bigsmile:

Not sure I’m following what you’re doing, but it sounds interesting. Highly flammable liquids and gasses are generally safe when in environment that is oxygen free. An example would be propane (R-290) used as a refrigerant. The key would be keeping it safely contained. It appears that you don’t have that nailed down yet. Texaspyro is correct, the flames are difficult to see at times.

Wishing you the best of luck and a safe build. Will be following as I love out of the box thinking.

Did somebody tell you a Molotov cocktail would be a great thrower?

Just don’t point it at your face so it could blast as further as possible :bigsmile:

This is hilarious.

How do you get enough current out of only two D cells, and alkalines at that, to generate any significant amount of heat, much less enough heat to benefit from liquid cooling? Or am I just not 'smart' enough to get it?

Someone please explain it to me, preferably using as many made-up technobabble nonsense buzzwords as possible, just to continue with the comedy theme.


moonlight mode:

turbo mode beamshot:

color: warm or, should I say hot white 3000K :stuck_out_tongue:


can we have a video of it being switched on please? preferably from behind high impact polycarbonate.

Please reverse course on this plan. I can't think of a single positive remark to make about this.


“Hold my beer… watch this!”

So far no one seems to have brought up the superior cooling properties of gasoline.