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karmagos1
12-24-2010, 04:08 AM
Which is the best ratio between KOH in 1litre water?

MtnGoatXJ
08-20-2011, 01:05 AM
I was given this recipe 860ml of distilled water and 140gr (5oz) of KOH on this board.

Thats roughly 25oz to a gallon of DS.

D.O.G
08-20-2011, 01:36 AM
I was given this recipe 860ml of distilled water and 140gr (5oz) of KOH on this board.

Thats roughly 25oz to a gallon of DS.

The maximum usable concentration of KOH is normally considered to be 28%. That's 720ml DW and 280grams of KOH.

The maximun usable concentration of NaOH is normally considered to be 20%. That's 800ml DW and 200grams of NAOH.

The above concentrations are normally used with a PWM to control current draw. Nothing says you have to use the maximum concentrations though.;)
MtnGoatXJ's recipie is a 14% concentration and will work fine in mild climates.:cool:

TimCollins
10-08-2011, 05:04 PM
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TimCollins
10-08-2011, 05:15 PM
I received my KOH 'Caustic Potash Potassium Hydroxide' and I am wanting to try out my generator for the first time. The generator is NOT installed in my truck. I will be running it on my workbench. Is there such a thing as a break in cycle for a HHO cell/generator? My plates are 18g SS. I did passivate them a few weeks ago. They are virgin plates. I read in another posting that with KOH I should expect discoloration and a film to build up. However, that film should NOT impact performance and is in fact a good thing. Please let me know if that doesn't sound right to anyone. So, my other question: If there is an 'optimum' break in cycle, what concentration should we use and for what timeframe?

I currently dont have a PWM, that is another project I am working on but I dont expect to have it test ready for a few more weeks. In the mean time I am looking forward to testing the generator by itself to gather some starting statistics. This question may not be exactly on topic, but is there a list of starting statistics that I should record?

Thanks for any help...

myoldyourgold
10-08-2011, 08:48 PM
I would suggest that you start with a low concentration because you are not using a PWM. 5% or less by weight. Then increase the concentration so that after running for 1 hour or more the temperature is under or not more than 110ºF. Lower the better. The coloration of the plates is normal and will not affect the performance if the stainless is 316L. Remember to keep the amps between .25 to .50 amps per square inch of active surface area of one side of one plate in a bipolar reactor. After passivation breaking in the reactor is not really necessary but doesn't hurt to run it at low amps for some time in case there are spots that were not passivated properly and to get flow right and electrolyte levels all the same in the the reactor. I would run it in a flooded state to start with and then lower the reservoir to find the spot where the production and heat is optimal.

TimCollins
10-08-2011, 11:35 PM
My math here has to be wrong?? I will try to keep this short... My setup is a simple dry cell 21 plates SS with 1/16" separation. Each plate has an active surface area of about 6.5"x6.5". Here is my current Neutral plates setup (I can change this easily if you feel there is a better configuration):
+||||||-|||||+||||||-
I believe Amps are regulated by increasing/decreasing the concentration of electrolyte (KOH in my case).
I am thinking that I probably need to invest in an ammeter to really know how many Amps the system is pulling inorder to really know what KOH concentration to use?

Anyway, where am I off in this calculation?

6.5" * 6.5" = 42.25sqin per surface
42.25sqin * 2surfaces/plate= 84.5sqin/plate
84.5sqin * 21plates = 1774.5sqin Total
Xamps/1774.5sqin = .25 Amps/sqin
Xamps = .25Amps * 1774.5sqin
X = 443.6Amps needed to produce .25Amps/sqin (that cant be right??)

myoldyourgold
10-09-2011, 12:05 AM
. Remember to keep the amps between .25 to .50 amps per square inch of active surface area of one side of one plate in a bipolar reactor.

IF you have 42.25 square inches on one side of one plate and 3 stacks then 42.25 x .25=10.56 x 3 =31.68 amps or 42.25 x .50 = 21.13 x 3 = 63.37 amps. To get the right active area you must subtract the gasket area, the the ports, and the dead space on the top of the plates where the gas prevents any electrolysis, so it most likely is less.

Active area on one side of one plate 42.25
Times the amps/sq/in .25 or max .50
Times the number of stacks 3

Your amp range is 30 to 60 amps.

What is really going to happen is at 30 amps you will only have 10 amps per gap/pair. Stacks divide the amps. Just remember cells divide voltage and stacks divide amps. Your setup is 7 cells 3 stacks.

TimCollins
10-09-2011, 02:52 AM
Once KOH is disolved in water will it stay in solution long term or will it precipitate if it is not shaken regularly?

myoldyourgold
10-09-2011, 01:34 PM
Once KOH is disolved in water will it stay in solution long term or will it precipitate if it is not shaken regularly?

NO. Once dissolved it stays dissolved. I do not throw away my old electrolyte but filter it and continue using it. I have no money to throw away!! LOL

TimCollins
10-09-2011, 09:52 PM
You might get a laugh out of this... I got some time this afternoon to mix some electrolyte. Not thinking much about it.... I poured precisely 5oz of KOH into 50oz of H2O for a 10% mixture into a 2liter coke bottle (yes it was empty and cleaned prior)... Anyway, it darn near melted the bottom of the bottle. I got scared and put it outside until things cooled down. Just laughing at myself now...

Also as things were cooling down and I was looking this up I found this bit of information on the web regarding KOH -vs- NaOH: "Potassium hydroxide is preferred over sodium hydroxide because its solutions are more conductive." - found it here: http://en.wikipedia.org/wiki/Potassium_hydroxide

Darrell
10-11-2011, 10:33 AM
That is why I mix my elite in a glass messuring cup and only small amount at a time. Mixing in plastic is not good and can leach the plastic properties into your elite.

"D"

myoldyourgold
10-11-2011, 12:13 PM
Use stainless steel to mix your electrolyte in. Pyrex or oven safe glass will work but I prefer stainless steel. Mix it slowly so you do not create to much heat. Do not breath in the fumes. Be careful!!! Percent is by weight not by volume. It is easier to use a hydrometer just make sure you measure at room temperature or compensate for the temperature when using a hydrometer. (Charts and links have been posted before) Like Darrel says electrolyte will leach stuff out of the plastic. Never store it in plastic it will start leaking over time and your results will not be as good if stored in plastic. I use large (10 Gallon) stainless steel kettles that are used in beer making. There are smaller (30 qt), thinner and cheaper ones available. The large ones are NOT cheap but easy to use with a spigot and site glass to see how much is in the container. Even the spigot is stainless. You can add a spigot to the cheap ones too. I mix max strength using DD (double distilled) water and then use it with DD water to dilute it to the strength I want to use. Winter gets max strength and the rest of the time a week mixture. I make my own distilled water or just re-distill commercial distilled water if I am in a hurry which does not happen very often.

The reason KOH is considered better is because it is more conductive at max concentration than NaOH at max. Industry uses more NaOH because it is cheaper. I use NaOH because it is readily available in just about all local markets places. In my testing in my setup it seems to maintain its concentration longer than KOH. I have no explanation for this and is just what I have found and might only apply to my system.

Darrell
10-11-2011, 06:35 PM
KOH seems to show up more in the vapor of the gas leaving the reactor and that maybe why the concentration is lost. I have noticed that the loss is even more when higher voltage is being applied. D

D.O.G
10-11-2011, 08:29 PM
You might get a laugh out of this... I got some time this afternoon to mix some electrolyte. Not thinking much about it.... I poured precisely 5oz of KOH into 50oz of H2O for a 10% mixture into a 2liter coke bottle (yes it was empty and cleaned prior)... Anyway, it darn near melted the bottom of the bottle. I got scared and put it outside until things cooled down. Just laughing at myself now...

Also as things were cooling down and I was looking this up I found this bit of information on the web regarding KOH -vs- NaOH: "Potassium hydroxide is preferred over sodium hydroxide because its solutions are more conductive." - found it here: http://en.wikipedia.org/wiki/Potassium_hydroxide

A minor point.
Using 5oz to 50oz is about 9% not 10%. You have to look at the total finished weight (55oz in this case) to calculate %.
A 10% mix would be 5oz KOH (10% of total) to 45oz Distilled water (90% of total).;)

arigatou
03-28-2012, 02:11 AM
In order to get the correct active area, you have to subtract the gasket area, port, and dead gas to prevent any electrolysis the top of the board space, so it most likely is less.