Author Topic: KOH and SS resistance  (Read 5781 times)

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KOH and SS resistance
« on: July 10, 2011, 19:58:47 pm »
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.
« Last Edit: July 11, 2011, 04:18:36 am by warj1990 »

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Re: KOH and SS resistance
« Reply #1 on: July 10, 2011, 21:23:01 pm »
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

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Re: KOH and SS resistance
« Reply #2 on: July 11, 2011, 03:23:24 am »
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. 

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Re: KOH and SS resistance
« Reply #3 on: July 11, 2011, 04:15:29 am »
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

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Re: KOH and SS resistance
« Reply #4 on: July 12, 2011, 21:39:15 pm »
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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Re: KOH and SS resistance
« Reply #5 on: July 13, 2011, 04:06:42 am »
Thanks for the tips.

Putting down one more graph of today's experiment.

This includes the graph from the other day also.


My next setup will be over-sized flat SS plates. (verify different surface area VS voltage needed).

My cell setup was not designed for high current, a #4 x 40 screw for outer electrode and #6 x 32 for inner electrode.

As you can imagine I am smoking the connections to these.  I need a # 8 wire, good for 50 amps, and I am going with Brass connection bolts.


I did attempt 1 run without KOH it was 4 amps at 88 volts.  Gas production did not seem impressive and the water heated up rather fast.
Gas production was improved with the KOH, results of higher amps.

88 volts * 4 amps = 352 watts
(maybe tomorrow I will run a voltage vs amps on just water - for power in right now it doesn't look good).
« Last Edit: July 13, 2011, 04:24:25 am by warj1990 »

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Re: KOH and SS resistance
« Reply #6 on: July 14, 2011, 04:07:06 am »
Wanted to post a thought on this setup. 

water is a voltage dependent resistor.  The higher the voltage, driving the system, the lower the resistance.  So the power input is about a squared function.

As an example
At 2.4 volts it draws 10.6 amps, Power is 25.44 watts. Resistance is (2.4/10.6) 0.2264 ohms.
At   4  volts it draws 37    amps, Power is 148 watts.    Resistance is (4 / 37)     0.1081 ohms.

I know what you are thinking, been looking over this all day also. There are 2 things to look at here.
1 the water resistance went down - so the cell can pass more current and be more efficient.
2, connecting 4 tubes together in parallel will achieve the same thing, 2.4 volts @ 42.4 amps.  This is still more efficient at 101.76 watts.

Now what IF...
You can achieve a high voltage pulse and deliver several amps low voltage?  This would be kind of like a flash circuit where the hv pulse allows the electrons to flow.  This is also similar to the plasma discharge spark plugs.

The big difference is how fast the water consumes the high voltage pulse. 

The high voltage pulse could be 12 volts @ 1 amp, 12 watts, while the high current is 2 volt @ 20 amps, 40 watts. 

Expected water resistance at 12 volts 0.055 ohms (need to verify this with more testing and data)
At this expected resistance the cell is able to handle (2 volts / 0.055 ohms) 36 amps.

So with 2 secondary windings on the transformer and a diode tied in from the high voltage to the low positive voltage we may be able to achieve greater than 100% efficiency.  (based on current known methods).
The grounds on both windings would be tied together on one end and sent to the ground of the cell.  The positive would be taken to the positive of the cell.

Current is going to take the path of least resistance, which is mostly the water with KOH added.

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Re: KOH and SS resistance
« Reply #7 on: July 15, 2011, 03:34:21 am »
No experiment time the last few days. 


I need to find a fast way to verify the voltage drop - is it due to the movement of water, because of the H2 and O2 causing the circulation of water, or because of the voltage alone.


I have only seen one brief article on water movement and resistance.  While it vague on a message board and the question was asked why did the water resistance drop when it was in motion.


So now the question is can I get lower resistance by just allowing the water to flow and not need the high voltage pulses.