Question on Dry cell at 20% NaOH Concentration

[keiththevp]

Ok my goal is to make a dry cell that will use a 20% NaOH solution as the electrolyte mix. Produce around 3-4 LPM at 40 amps. I have a total of 42 6 x 6 plates and 84 gaskets that are each 1/16th inch.

I have tried a 7 plate 5N with 3/16 gaskets .....

Outcome 1 lpm, 16 amps, no heat issues

I have tried 13 plates 5N with 1/8 gaskets ......

Outcome 1.5 LPM, 26 amps, no heat issues

I have tried 11 plates 4N with 1/8 gaskets ......

Outcome 3 LPM, 55 amps, and SERIOUS heat issues

My next test is 11 plate 4N 3/16 gaskets ....
and 13 plate 5N 3/16 gaskets ....

So my question to those that have used a full concentration of electrolyte is ... What would you recommend? Should I use more plates, and what gasket size?

I have achieved 4 lpm at 50 amps with no problem at low concentrations but I just can't seem to get it to work at full concentration. Any help or ideas would be greatly appreciated.

Thanks,
Keith

[Roland Jacques]

When you’re testing, record your MMW in each configuration, MMW paints a clearer picture for comparison purposes IMO.

It looks to me that your 4 LPM at 50 amps is a very good MMW (assuming your voltage is the same as the other tests 13 ish) it looks to be about 20% better than you best of the higher concentration test. If your heat not contributing to that number it seems very good. Your 4lpm@50 may be very hard to beat.

Personally id try KOH instead of Noah and see where that gets you.


I have another line of thought that may be way off, but may explain some things that I have run into when dealing with different concentrations of KOH. Anyway the other thing I'm thinking is the different electrolyte concentration will effect water tension differently. I don’t know that this has really been looked at, but I do know that the higher you raise the specific gravity (concentration) the smaller the bubbles are. So what if higher concentration electrolyte makes bubbles more likely to stick to some plates, (sanded plates in particular) this could actually slow down production. I’m thinking if your production goes down but your MMW stays the same this could be the problem. Just a theory.

[H2OPWR]

Ok my goal is to make a dry cell that will use a 20% NaOH solution as the electrolyte mix. Produce around 3-4 LPM at 40 amps. I have a total of 42 6 x 6 plates and 84 gaskets that are each 1/16th inch.

I have tried a 7 plate 5N with 3/16 gaskets .....

Outcome 1 lpm, 16 amps, no heat issues

I have tried 13 plates 5N with 1/8 gaskets ......

Outcome 1.5 LPM, 26 amps, no heat issues

I have tried 11 plates 4N with 1/8 gaskets ......

Outcome 3 LPM, 55 amps, and SERIOUS heat issues

My next test is 11 plate 4N 3/16 gaskets ....
and 13 plate 5N 3/16 gaskets ....

So my question to those that have used a full concentration of electrolyte is ... What would you recommend? Should I use more plates, and what gasket size?

I have achieved 4 lpm at 50 amps with no problem at low concentrations but I just can't seem to get it to work at full concentration. Any help or ideas would be greatly appreciated.

Thanks,
Keith

Your problem with full concentration will be thermal runaway. As your cell heats up your amps will climb and climb. I use even higher concentrations than 20%. I control the amps with a PWM. If you continue to run high concentrations of electrolite you will need to use a PWM to control amps eventually. There is no getting around it. With no PWM you control your amps with lower concentrations of electrolite.

As for plate set up I would try +nnnnn-nnnnn+nnnnn-nnnnn+nnnnn-nnnnn+

Larry

[keiththevp]

Roland

As far as MMW I have done a lot of testing and calculated the mmw's but to be honest I think for what I am looking for it is a waste of time. I have found that I can get 1 LPM at 10 amps 13-14 volts in a dry cell with low concentration which is a great MMW however this is not practical to pay for and install 4 of these cells to get to my goal. So if your aim is efficiency then yes I agree with you but if you are just trying to hit a certain point and you can not change the electrolyte it doesn't help more than just a rough comparison of the 1LPM per 10 amps.

H20

I agree that with high concentration you can run into thermal runaway if you don't have enough neutrals and a large enough plate gap. However all of my tests with 5N and 3/16 gaskets have never gone over 100 degrees at full concentration (8 hour tests) so I do believe that you can use the plate size and gasket thickness and neutrals to control your heat. I do have a couple PWM's from Shane on this forum however I have found that they do help to control heat but offer no added increase in production. Also they will only control the cell to a certain point. For example if I have a cell that starts off at 40 amps cold and goes to 100 amps after 2 hours it will burn out the PWM. But if I have a cell the starts 40 amps cold and goes to 80 lets say after 8 hours I have no problems with that pwm at all. I guess it should be possible but maybe I should just get a PWM specially made that can withstand a large amp draw and start using that to get the LPM I want as well as control the heat.

[keiththevp]

Also just so I make it clear I must use a full 20% concentration of NaOH because of freezing issues, as I have yet to find anything else that will not freeze and also not kill your rate of gas. That is the purpose of developing this cell.

Thanks for all the help guys,

Keith

[H2OPWR]

Also just so I make it clear I must use a full 20% concentration of NaOH because of freezing issues, as I have yet to find anything else that will not freeze and also not kill your rate of gas. That is the purpose of developing this cell.

Thanks for all the help guys,

Keith

That is why I use strong concentrations of KOH in water. I need to control freezing. I have made many cells to try to improve effeciency but I have never acheived 1 lpm at 10 amps with normal automotive voltage. What are you doing to get that kind of production? It is taking me 13 amps to get 1 lpm at 13 volts and that is with the best cell that I have tested yet. That is with cold gas.

Larry

[keiththevp]

h2opwr

It was at least a couple months ago when I was testing with low concentration but to the best of my memory it was either a 4n 16 or 4n 21 plate dry cell with 6x6 plates and a slit piece of tubing in the water inlet holes to help with current leakage. I don't know the exact concentration but I know it was LOW and this was a cell that had been completely conditioned. Also the amps could have been realistically upto 12 since I used to use a large batter charger as a power supply, which works fairly well but can give unpredictable and/or unreliable results versus hooking up straight to a car battery. That is why I only use a running vehicle now. But still I would say that it was definitely in the range of 10-12 amps.

Also a side note on cold or hot gas. I could be completely wrong here but I have run a cell for a couple hours, checking the output every 15 min at a constant rate of 2 LPM and the temp was at 150 degrees. It was steaming like crazy, now I know the gas was being contaminated but I don't believe it changes the volume all that much because I also hooked a LARGE bubbler in line and drop the gas temp immediately to 80 degrees, re-checked output and it was the same for the next half hour or so. The only reason I did this test was to see if I really needed the bubbler hooked up every time when I was just testing for volume. Just some food for thought. Even though a steaming cell is completely useless at high concentration because there is too much NaOH in the gas stream.

Also I just tried a new product today that is called Main Line Clog Remover. They sell it at Menards and it is made of 28% NaOH and 2-5% KOH and distilled water. (per the manufacturer help line) This stuff works great and saves me time and money mixing high concentration solutions. Also got me to thinking that I don't believe anyone has ever used both NaOH and KOH in the same system.

[H2OPWR]

h2opwr

It was at least a couple months ago when I was testing with low concentration but to the best of my memory it was either a 4n 16 or 4n 21 plate dry cell with 6x6 plates and a slit piece of tubing in the water inlet holes to help with current leakage. I don't know the exact concentration but I know it was LOW and this was a cell that had been completely conditioned. Also the amps could have been realistically upto 12 since I used to use a large batter charger as a power supply, which works fairly well but can give unpredictable and/or unreliable results versus hooking up straight to a car battery. That is why I only use a running vehicle now. But still I would say that it was definitely in the range of 10-12 amps.

Also a side note on cold or hot gas. I could be completely wrong here but I have run a cell for a couple hours, checking the output every 15 min at a constant rate of 2 LPM and the temp was at 150 degrees. It was steaming like crazy, now I know the gas was being contaminated but I don't believe it changes the volume all that much because I also hooked a LARGE bubbler in line and drop the gas temp immediately to 80 degrees, re-checked output and it was the same for the next half hour or so. The only reason I did this test was to see if I really needed the bubbler hooked up every time when I was just testing for volume. Just some food for thought. Even though a steaming cell is completely useless at high concentration because there is too much NaOH in the gas stream.

Also I just tried a new product today that is called Main Line Clog Remover. They sell it at Menards and it is made of 28% NaOH and 2-5% KOH and distilled water. (per the manufacturer help line) This stuff works great and saves me time and money mixing high concentration solutions. Also got me to thinking that I don't believe anyone has ever used both NaOH and KOH in the same system.

Trust me, A 150 degree steaming cell will skew the test results alot. The bubbler only touches the outside of the bubble leaving all the steam and expanded gas alone in the rest of the bubble. You will need an elaborate and very large bubbler to make a difference in moisture content of the gas. Hot gas takes up much much more volume than cold dry HHO.

Larry

[keiththevp]

Shane

When you say you used several of your PWM's do you mean that if the cell draws 120 amps cold for example you would hook 3 PWMs individually on each ground so that each one is only controlling 40 amps at a time? I just assumed it would be easier and cheaper to have you build me one PWM that can handle the full load. By the way just so there is no misunderstanding I was NOT knocking your PWM's they are GREAT!! And you have by far the best price!! But I am definitely going to come to you for a custom one when I figure out exactly how I want to configure my cell.

[keiththevp]

The bubbler I use is large and also has two inputs with 3 inch 100 micron air filters that drastically reduce the bubble size so that is why it is capable of cooling the gas so well. I used my laser temp gun to verify. It's funny I have been using these filters for months and they just now came out with them at hhoglabs.

[keiththevp]

H2OPWR I just noticed you are in AK! Does a 28% solution of NAOH really not freeze until 60 below zero? I figured you might actually have had the ability to do a real world test in your neck of the woods. LOL

[H2OPWR]

H2OPWR I just noticed you are in AK! Does a 28% solution of NAOH really not freeze until 60 below zero? I figured you might actually have had the ability to do a real world test in your neck of the woods. LOL

I have never been in -60F. It can get there in Fairbanks from time to time but the coldest I have seen where I live has been -35F. I had a glass jar with 28% KOH outside most of the winter just to test it. There were many many nights and days that it was well below zero and not even one ice crystal ever formed. So to answer your question unless, yes it works very well to stop any freeze up. You just have to add alcohol to your bubbler to keep it from freezing as well.

Larry