While out for a winter walk I sometimes I turn on a light and let it run a bit so it will warm up the light, and then my hand. Anybody else do this :face_with_monocle: ?
So it go me wondering if there are any battery-driven hand warmers that can use our flashlight batteries? Lord knows I have more batteries than I could ever use at one time and wouldn’t mind some kind of hand warmer that I could run. Do these exist? I would think one or two 18650’s could work pretty darn good in such a purpose.
A triple XM-L P60 drop in will warm your hand just by pointing it at your hand. ;) I'll admit I have wondered the same thing though.
cabelas has some relatively new heated clothing items that i believe are powered by li-ion
but, due to cost, and difficulty of recharging, or carrying large numbers of batteries, I’m sticking with fossil fuels
http://www.sportsmansguide.com/net/cb/great-outdoorsman-pocket-warmer.aspx?a=1113661
i have the same theory on camping lanterns - tough to beat white gas - a quart makes a LOT of light…
Considering that its still only a tiny fraction of energy thats converted to light by LEDs.. just buy a small host with a 2A driver and you will have a light generating pocket hand warmer. :D
A small flashligt in the glove provides heat. If the light does not escape from the glove it must be converted to heat (as well as the normal losses which is the majority of the power).
If you need no light at all, you might consider for example a led from a flashlight and adding a linear driver to make just resistive losses. You might replace the driver with a resistor if you need no modes. (With multimode linear driver you’d get modes like hi/lo etc as well!)
actually, that’s a pretty good idea, especially if you have a host available that would otherwise be junk, or at least not worth fixing.
at least you can avoid smelling like butane w/ such a device, as opposed to what i posted 
Figure that a good LED “wastes” 10% of its input power in the form of light, the rest is heat. Any flashlight on high/turbo makes a dandy hand warmer.
But if you put your hand in front of the lense than you can capture a lot of that light back up.
I collect it in a jar and save it for later…
Your post made me smile…
When I was a pup, my dad had a hand warmer that worked off of lighter fluid. It was a neat looking thing, chrome if I recall and in a green cloth bag. We went fishing early one spring and he had it in his coveralls pocket. I recall hearing him rustling around then letting out a real war hoop!!! I looked over and he was totally ablaze! The lighter fluid had leaked, soaking his coveralls and setting them on fire. He bailed in the lake like it was a warm July day! Ha! It was really about 40 degrees and the water was much colder than that!!
He wasn’t hurt … MAD AS HELL but not hurt… so it was hilarious!
Thanks for the smiles! Dan.
Haha if only it was that easy! I wear 2 pairs of gloves when feeding my horse in the winter and I still can’t feel my fingers after a minute or 2!!
I would be very interested in a product like this as well, although I would prefer it powered by NiMH cells…
Hmmm... I think I may have found another use of triple P60. "A great handwarmer, and it even produces light!" :P
I have some gloves that will keep your fingers toasty at –40F/-40C… you can’t do much with your hands while wearing them, though. At least they will keep your fingers from falling off.
Same ones are also on ebay.
Maybe experiment with nichrome and kanthal wire. Or maybe some other form of resistance wire. Problem is, the only experience I have with it is ecig use. That and strip heaters at work. I’m sure the strip heaters aren’t either of those materials, but basically uses a resistance to convert electricity in to heat to preheat steel for welds.
With nichrome or kanthal you will need to use a significant amount more than what is used for an attomizer. An attomizer will use about enough to equal around 1.2 to most likely upwards 6 ohms resistance. A wild shot in the dark. I’d say you’d want something in the range of 50+ ohms.
Now I have never worked with the stuff, and can’t say that 50 ohms is what you’d want to use. All I know is you would most likely want to insulate the resistance wire in something non conductive like ceramic.
I also can’t say whether or not its the most efficient way to go about this
And I’d also like to say that using a lithium battery is probably not safe to deliberately heat up…
Now you only have to take it apart and install a 3 amp driver with ramping! :P
I know what you mean, I could wear snowboarding gloves but I need to undo buckles on rugs etc which is hard even with light gloves on. Luckily, its not that cold here that fingers would fall off though!
Stumbled across this
Ultra Heating Fabric
Spec sheets: