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

this isnt a good idea
thank you very much
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 ...
If your worried of explosions (which I doubt) you could use a resistor of the right value.
terrible idea. Shorting a battery can make it explode emphasis on <em><strong>EXPLODE</strong></em><br/>
I believe all batteries sold in the US are required to have vents to vent gasses outward to prevent &quot;kasplosions&quot;. This includes AA, AAA, C, D, and 9v batteries. Older batteries do not have vents, which is probably where you got this idea. <br /> <br />
I still wouldn't trust it...safety concern, but it is a good idea other then that...<br />
Oh ya and <em><strong>!EXPLODE!</strong></em> if you didn't get that from above.<br/>
9-volt battery 101 the 9 volt battery has a thick metal casing,worst case scenario:the battery leaks acid
Thats why I said Not emphasis on Not to leave the battery attached to the heater
Yes but what if it <em><strong>!EXPLODES!</strong></em> in your hand/glove or anywhere else some might put this.<br/>
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.
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. <br />
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?
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.
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
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!
how hot does this actually get? i have made several 3 or 4 watt heaters using resistors, and they aren't shorting the battery.
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....
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
Well that couldn't at all pose a firehazard.
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.
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.
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.
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
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
wouldn't doing this short circuit the other nine volt and cause it to heat up as well?
yea so, double the heat. i would a designed differenty tho
Word of warning here. If you were to dump that on a table and put the 9V tips to it, it would light on fire, or get hot enough to glow red and catch other things on fire. (handy tip if you need to light something on fire and don't have a match) Being that this is in an enclosed space, there is always the possibility of flames, fumes, or explosion from the steel wool. A burn from hot metal is a bit more painful than a burn from an open flame, as the metal can reach higher temps. That having been said, not a bad idea.
surprisingly the battery lasts a while
(If you'd hit the reply button on <strong>mlcorson</strong>s comment he would've got a notification that you did so)<br/><br/>Does the battery it's self get hot or warm?<br/><br/>L<br/>
I forgot to mention not to leave the battery attached. Attach the battery in pulses. the battery itself gets hot if you leave it on.
That's what I thought. If you used more wire the battery might get warm <em>enough</em> without getting too <em>hot</em>. After all the chemical energy in the battery is being converted to heat either way.<br/><br/>L<br/>
You'll need a steady supply of batteries. How long does the battery last?

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