shadfurman

Makes, Projects and other general trouble.

First major failure… Yay!

So, I retested the last cell I made, open air… Nothing. I think the aluminum foil was damp. I made a larger one this morning. I glued a paper towel to a piece of aluminum, cut out strips and progressively wrapped pennies up separated by paper towel.

image

image

Utter failure, I’m only getting 275 mV in tap water, adding salt made it worse. Only 125 uA. It’s possible my meter is malfunctioning, it’s a cheap harbor freight one.
image

But I think the pennies moved and are shorting inside. This is a little more complicated than I’m looking for, kids are supposed to be able to do this, and it didn’t work so…. On to something else.

Advertisements

Aluminum air battery

I was playing with different electrolytes with a copper aluminum battery; penny wrapped in a paper towel wrapped in aluminum foil. I dumped out a failed mixture of who God knows what, everything I added made it worse, and had it hanging over the edge of the sink; as it dripped I noticed the voltage increasing. I have read about carbon aluminum air batteries but have yet to try one. In about a minute it stabilized at about 700 mV and 300 uA. I replaced the paper towel with a dry one and wrapped another penny and aluminum on for just under 1.4 V with two cells and an air electrolyte. I think the aluminum wrapping around the back may be canceling out the voltage some; since the air is the electrolyte they aren’t really separate cells, just high resistance between them, but since the current flow comes from oxidizing of the aluminum (I think) I’m not sure if it matters. Supposedly potassium hydroxide in water as an electrolyte will accelerate the reaction as well as produce hydrogen… Which could be used as a burn assist in a gasoline engine? If I can get the necessary amperage I may have to try that in my car.

sink battery

So, part of the problem with my previous batteries was the low amperage. I can add on cells to increase voltage no matter the size, but the amperage is only going to increase with a decrease in internal resistance, either in the electrolyte or the surface area of the electrodes.

Everybody has stainless or iron pans, aluminum foil and salt. I put a few inches of salt water in the bottom of my stainless kitchen sink, and floated a sheet of aluminum foil just below the surface. This produced about 200 mV, I added a packet of Emergen-C and that bumped it up to 300 mV and 10 mA sustained. When I added hot water and lightly agitated and was able to get it up to 600 mV but it always settled down around 400 mV.

But to get 12 volts would take 40 cells, kinda unfeasible to string 40 pans around the kitchen in an emergency.  17 pans for 5+ volts to charge a cellphone… still unfeasible.  5 pan cells would be 1.5 volts… enough to charge a AA battery, but only 50 mA, slow charge of only one battery.

I think next I’ll try aluminum and carbon.

Squishy Battery

I’m working on a beginner electronics kit with squishy circuits conductive clay.
Here’s a battery…

image

This is a coin battery with conductive clay as the electrolyte. It produces 2.25 V and 200 uA. It didn’t matter what coinage I used as long as I used aluminum on the cathode (or is that anode, I get them mixed up). This one is made up of 5 cells. 2 nickels, 2 pennies and a dime.

First Crude Homemade Batteries

Some batteries I’ve been experimenting with. Trying to find the most efficient battery that can be made with homemade materials. These are made with stainless steel and aluminum electrodes in a saltwater and hydrogen peroxide electrolyte. I’d like to get at least 2 volts out of one cell so that it can be used to charge AA batteries without a converter. I was able to get 1.4 volts and 6.8 mA out of these two crude cells. Next I’m gonna try in my stainless sink with a sheet of aluminum foil. I don’t think I’ll get higher voltage out of these materials, any suggestions?2013-03-23 17.11.01 2013-03-23 17.10.36

First Post

Nothing here, just posting to post something. I’ll post some old projects with some pictures and hopefully get into new projects soon. I’m currently disassembling a printer to make a 3D printer, I think I may need a few more for more parts, but there are a bunch available for free on craigslist, and eventually I’ll have to pay for a heated bed… though I’ve been thinking about using the glass from a scanner and run some resistive wire… have no idea if that will work… we’ll see… the point it to make a 3D printer without buying any parts.

I am the founder (if I can find other makers) of the Fall River Makers Club (MA). I’ll be posting on that as events unfold. (Fall River Makers club never really took off and I haven’t lived in Fall River for quite some time.) I’m interested in being involved in education, after school programs and scouting with making. I didn’t have a community when I was young and wonder what might have happen had I more coaxing, direction and education. I am a huge believer that problem solving is universal and so much else in life is just contextual knowledge. We put too much emphasis on being an architect or a biologist, I believe we can all be them all. I look to the John Carmacks and Elon Musks of the world for inspiration. I believe every child should learn to program and repair their own car. The logic and problem solving skills are more important than KNOWING anything.

….thats all on my mind at the moment…