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KOH and SS resistance

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warj1990:
Wanted to look into / document KOH mix and current draw.

This setup is with a single tube in tube design.

1/2 inch inner tube, 3/4 inch outer tube spacing about 1/8 inch round. 6 inches overlap.
Inner (limiting) surface area: 0.5 * 3.14159 = 1.57 inches * 6 inch length = 9.42 inches
The surface area is equal to 3.07 inch square plates.
 
I did not measure the KOH put into the cell.  I am simply documenting Voltage vs. Current draw.

I have read 28 % KOH by weight is the best mix, for the amount I applied I am well beyond that ratio.

Both tubes were SS 316L material.
The bridge is rated 1000 volts at 100 amps.


Overlooking barrier voltages needed I am putting the effective resistance of the cell also.

VBB = Voltage before Bridge rectifier
VAB = Voltage after Bridge rectifier
A = Current draw
R = Cell resistance (R = V / C)
W = Watts (after bridge source)

VBB                  VAB                       A               R                      W
2.79                 1.7                        1              1.7                   1.7
3.1                   1.9                        2              0.95                 3.8
3.5                   2.1                        4              0.525               8.4
3.7                   2.2                        5              0.44               11
3.9                   2.3                      10              0.23               23
5.2                   3.1                      18              0.172             55.8
Adding from the other day:
                        3.3                      32              0.103            105.6
 
It is difficult to get good measurements using a Variac at such low settings and minor changes.  I did see 40+ amp draw at one point. I quickly lowered the variac before looking at the settings( amp meter and 2 volt meters).
I am thinking that was about 6-7 volts before bridge.

As far as I know this is the best setup we can do - as all research points to KOH as the best electrolyte for brute force.

Some changes would be to mix the electrodes and gain some voltage  the galvanic corrosion chart comes to mind, but I have not tested any other metals lately.


This setup shows the resistance is lowering for each increase, but the power is increasing also.
(question remains why did my driver take so much power at HV if the cell continues to drop resistance?)

Edit added graph of above results.

kickbackemf:
I'm still working with purified water and have tried an interesting experiment in the hopes of lowering amp draw.  My three inch long by 1 inch 304 tubes with 1/2mm gap and with the inner filled with epoxy are set up in a RO water bath.  What is new is that I've also added some clear thin plastic tape to the inner negative tube by wrapping it around completely but leaving a 1/8 inch exposed gap around the middle of the inner tube.

Gas production has increased x4 and the bubbles are large and fast with little milky production seen.  The tubes and water do get hot but the coil and mosfet stay cool at 100v and 1 amp on the meter.  Playing with frequencies and have noticed some better production when I can get the thing to sing and hum on the bench top.

The big bubbles may be boiling water since the current is limited to the area where the tape is absent, although they are evident at 5v and .1a as well as higher power levels.

kb

warj1990:
kb,

I could not find your projects page, if you want I will post a topic here for you to share your progress. (or maybe I just overlooked it on this form?)

Basically what you are doing is increasing the current density to a smaller area.  My cell has an open top at present - so I have no way to verify gas production except by amp draw alone, Faraday.

How are you measuring yours to verify 4x production?

Right now I am trying to figure out how to produce more current draw at lower voltages.  I am thinking 2 areas here:
1, larger cell size - going super sized on the electrodes should allow more ions between the electrodes.
2, moving to a plate cell and making the gap smaller.

The farther outlook plan is attempt dissimilar metals on the cell.

My overall goal is achieve the low resistance (0.1 ohm or lower) without the need for the higher voltage.  I think the SS has a lot to do with this.

Secondly overall goal is try again with the resonating tank circuit, maybe build a better driver that doesn't walk the frequency, but the auto tune is designed for maximum efficiency. 

kickbackemf:
production measured via closed top and water displacement over time, pardon the thread highjack...
I'll light it up this next week and see what we get from the torch.  The flame never lies.
I may have been reading your post and left to take care of something and later returned and replied instead of starting a new post.....  yah, that's my story

Steve:
WJ,

Please do not forget one big factor in measuring.
Temperature of water has a great impact on your measurements.

So, when you put NAOH or KOH in water, it will release heat.
1 degree raise will provide in pulling more amps.


And to give you some more advise in this case. I found out that till around 10 till 15 amps, its better to use NAOH.(20 till 25%)
If you go up into higher amps, you better use KOH.(28%)
Both are very nasty chemicals.....my hands sometimes burned like crazy.......No cloves. ::)


Steve


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