Picture of Free Electric Hand Warmer/Stove
Small nine volt heater. Stop at step three for the case and the battery clip.

Step 1: Tools And Supplies


Ni chrome wire or thick steel wool type thing, different thicknesses and lengths heat differently. Some wire will need more voltage to glow red hot.

9 volt battery w/ metal case


Some kind of adhesive


Soldering iron

Utility knife

Flat head screwdriver

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Xixfas2 years ago
this isnt a good idea
najito3 years ago
thank you very much
hanlin_y3 years ago
It may be safer for you to use a 5W power resistor and mount it to the metal case. That way, you can control the current with I=V/R. 0.5A is okay for AA batteries.
Here's a safer way to do this, get a small 12v bulb such at those used on car interior (dome) lights & wire it to an old 9v battery top as you've done here. Safe & cheap,cheap, cheap ...
dog digger4 years ago
If your worried of explosions (which I doubt) you could use a resistor of the right value.
Wesley6666 years ago
terrible idea. Shorting a battery can make it explode emphasis on EXPLODE
I believe all batteries sold in the US are required to have vents to vent gasses outward to prevent "kasplosions". This includes AA, AAA, C, D, and 9v batteries. Older batteries do not have vents, which is probably where you got this idea.

I still wouldn't trust it...safety concern, but it is a good idea other then that...
Oh ya and !EXPLODE! if you didn't get that from above.
Derin Wesley6666 years ago
9-volt battery 101 the 9 volt battery has a thick metal casing,worst case scenario:the battery leaks acid
LaxLuvr (author)  Wesley6666 years ago
Thats why I said Not emphasis on Not to leave the battery attached to the heater
Yes but what if it !EXPLODES! in your hand/glove or anywhere else some might put this.
LaxLuvr (author)  Wesley6666 years ago
Then I hope you have insurance and/or a spare hand!
Unless your a guy and want so warmth down there then you better have another one of those.
LaxLuvr (author)  Wesley6666 years ago
just connect 2 nine volts together with a switch in between faster and easier but be careful because it does get super hot and will burn you very badly if used incorrectly.
mm4054166 years ago
I realize that this would add cost and detract the ratio of recycled materials, but isn't there some sort of IC you could put in line and would complete the circuit in pulses so that you could leave the battery attached for significantly longer?
LaxLuvr (author)  mm4054166 years ago
Thats a good idea but considering I'm 13 and don't know too much about electronics I would have to learn more about electronics if I wanted to do that.
dodo91 LaxLuvr6 years ago
im 13 too!
I am 13 too
Research into 555 timers I once saw a guys website that used one of these to power a mini Tesla coil. It used a 555 timer, transformer, 2 9v batteries, and a ceramic capacitor bank. Worked rather well in my opinion :D Just a thought
luvit6 years ago
i once made a hand warmer. i took two 9v batteries and plugged the sockets into each (plus to minus). i did a lot of things during church service when i was young. i don't know why i had two 9v batts at church.
lol prob for the wireless mics!
in 1986 church mics without wires were unheard of... or it was a mic in need of wires.
back-n-the-day....ha ha ha ha ha!
junits156 years ago
how hot does this actually get? i have made several 3 or 4 watt heaters using resistors, and they aren't shorting the battery.
LaxLuvr (author)  junits156 years ago
I don't actually know how hot it gets. I like your idea! I have used a resistor to make a putrid stink machine but it was a real pain trying to find one that reached a high temperature, especially when powered by a nine volt battery. I hope this helped to answer your question and if you have any tips on how I could improve my idea I would appreciate them.
to improve it, you could use some nichrome wire it is a much better heating element than the steel wool
better.......a COIL of nichrome...just make sure its insulated....
sharlston6 years ago
you can get real hand warmers at hiking shops for £7 or $15 and you light the little sticky of charcoal and put them inside
A good name6 years ago
Well that couldn't at all pose a firehazard.
dodo916 years ago
want a hand warmer. i learned this the hard way. like he said, it will short the battery. if you connect two full 9 volts together, they will star to heat up.
this could be used as a fire starter. but be careful.
backscan6 years ago
Not sure on how green this is but it's a cool (sorry for the pun) idea but I was wondering if this could be improved by adding something like vegetable oil or a small water bag to the case with the steel wool to act like a heat sync and keep the wire cooler while allowing heat to build up and last longer between on and off time.
miiwii36 years ago
P.S battery acid deosn't hurt as bad as you think Its more of a paste than liquid. And sorry about the other comment I Wasn't trying to be mean really.
miiwii36 years ago
htis isn't green because it's a waste of batteries. as you may know when you short a battery you shorten It's life therefore using more batteries, going through more metal and chemicals( the ones in the battery I mean). Sure you used a dead battery as the case and the wool was recycled But that doesn't save the planet! I DON'T WANT TO BE MEAN BUT THIS ISN"T GREEN
dalbyman6 years ago
Ive been doing this for years, only ive been using it as a makeshift bomb detonator. Every time i have done this unless the battery is flat the wire just goes red hot and burns for a second or so before breaking. Are UK batteries better or something :s
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