Alle Beiträge und Antworten zu "Aku 2"
Re: Aku 2
Erbse - 27.05.2012, 18:21
The Negative Electrode
Forming the negative cell requires only filling tubes (or any other nickel plated metal
packets) with the pure iron oxide (Fe3 O4) under pressure.
Most texts state that the purity of this oxide is absolutely critical, so a laboratory grade
oxide is recommended.
Note: An important aspect of the negative electrode is that most battery designs allow for
an over sized negative electrode. (This electrode can have a larger surface area than
your positive electrode by as much as 30%.)
Gassing usually increases when the negative electrode has reached a full charge, so by
creating a cell that is fully charged before the negative electrode takes on a full charge,
gassing is greatly reduced.
A lot of mythology surrounds the electrolyte, and it’s mixture is fairly critical. The video
was fairly good at showing a great mixture. However higher and lower concentrations of
KOH can have interesting effects.
For example 1.25 g/ml of KOH to distilled water gives the longest life, while 1.34 g/ml
gives the highest output (and greatly helps the cells resist freezing in cold climates).
This could be very useful for those going “off the grid.”
Another popular item floating around the internet is the addition of lithium hydroxide to
The popular misconception is that this adds to the cells capacity. In actuality, lithium
hydroxide decreases the cell’s capacity somewhat, however it has a protective effect on
the cell during conditions of high temperature cycling.
If you choose to use KOH and lithium, the mixture I’ve been most pleased with has been:
Potassium hydroxide 1.3 g/ml, lithium hydroxide 15 g/l
The Homemade Cell II
With all the above in mind, I set out to make a greatly improved “hobbyist cell” for all of
us that was just as easy to make, but of real practical use.
This cell could be both used for a project, or as the basis for creating your own larger
cells; all with MUCH simpler manufacturing.
I have two cells produced by the following method that produce about 1 Ah of output per
In researching small battery electrodes, I found that many manufacturers created flat
plates (like those in the video) containing oxide particles with a high surface area.
This was accomplished by HEATING the nickel plate until it was slightly molten, and
then pressing the oxide particles against it.. As the plate cooled, the oxide particles were
slightly melted into the surface. This gave the metal a sandpaper like surface with very
high surface area and great conduction to the oxide.
I tried this method, and found what it created for me in all instances was what we call in
scientific terms “a big mess.”
But, I mention it in case you want to give it a whirl as it’s a good manufacturing idea.
In trying to think of ways to get the same effect without heating and pressing, I began to
think of conductive paints and epoxies.
I first nickel plated two steel plates to be my electrodes. I have a youtube video up that
shows the nickel plating process at:
I then used some simple silver bearing epoxy (nickel epoxy might be even better, and is
cheaper) and coated the electrodes with this conductive glue.
Note: I strongly recommend getting an industrial quality silver bearing epoxy that is no
more than 3 months old. An excellent company for “fresh” industrial epoxy is Ellsworth
I then coated one electrode with nickel II hydroxide, and the other with iron oxide (Fe3
I allowed the electrodes to dry over night.
Using these two metal parts as my electrodes, I assembled the cell as shown in the video,
with two small changes,
First, all internal electrical parts (including wires) should be nickel, or nickel plated.
Nickel wire is fairly easy to find, and the screw terminals on top are fairly easy to plate or
And second, I added 2mm of mineral oil to the top of the cell.
Without the mineral oil, your electrolyte will discolor in a few weeks, and lose some
I have a variety of additional experiments near completion, and plan to double the size of
this “white paper” in the coming weeks with many additional tips and tricks.
As I said, one thing that has slowed me down is waiting to make SURE things hold up
before I pass them on to you.
I’ve tested the epoxy in a cell for over a year, and it is still holding up!
I also have a home made plastic conductor that is a fraction of the price, easy to make
yourself, and creates a flexible electrode so you can assemble a home made cell in the
easy “jelly roll” fashion that capacitors and commercial batteries use to run by you soon.
Hopefully you’ll be creating cells that are lifetime, and we can all get off the grid!
A professor at a junior college I went to had a Volkswagen powered with Edison Cells.
These Edison cells were from an old power station and were more than 50 years old!
Yet, they still gave the Volkswagen a range of 100 miles and 55 MPH… all with off shelf
At this point I’ve literally spent many hundreds of dollars and countless hours separating
the fact and the fiction on these cells to distill everything down to just a few pages for
your research for you.
I hope I save you an immense amount of time should you choose to go “off the grid” and
make your own cells for your use or profit.
Here is what I would like to ask of you, and it’s completely up to you if you think this is a
I will further expand this white paper with my ongoing results of the home made cells,
tips, sources and make all materials available to you.
I’ll include all the data I’m collecting now with my cells on charging your cells for the
first time (which is important for perfect formation), and ways to extend cell life, and, I’ll
include the info that’s going into the formal article I’m working on. But, the last thing
that’s slowing me down is honestly the expense of the next round of laboratory oxides,
nickel plates screens etc.
It has added up to a surprising amount over time, and so far is just a hobby we’re
I was thinking that what I might do is put up a donation link and send out the new
expanded whitepaper to those who can make a small donation to the cause.
This is not a for profit link, but a for chemicals/metals link. I was thinking of asking
maybe $10 or $12 for the whole definitive white paper which is coming soon..
If that sounds uncool, no one is obliged. But if it’s possible, it would definitely help a
great deal to get this done. I think we’re very, very close to having really practical cells
we can make ourselves!
Write me if the link sounds like an OK thing to do.
Thanks again for your interest, and I look forward to seeing where all this interesting
P.S. I’m going to cut and paste below a list of links and comments that were sent to me
by other builders that you may find useful. I don’t know the quality of these sources, but
just wanted to pass them on.
For screens and other parts:
Leybold Didactic GmbH
Phone +49 02233 604 - 0
Telefax +49 02233 604 - 222
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