OK, so the individual cell Vf is 2v with the higher concentration.
This is actually more of a "wall" than I expected. Pretty good as a Zener diode

Back to the power dissipation thing. With the higher concentration of electrolyte and using 5 cells, with the 10.4A flow, you're dissipating 20.9W per cell for a total of 105 Watts (rounded off). You still have a pretty severe power (heat) dissipation problem.

You need some way to get rid of that heat.

You won't be able to use a single radiator for the five individual cells, because there would be a current path through the electrolyte streams when they merge.

Oh, and stainless steel is great for it's corrosion resistant properties. Unfortunately, it's a lousy conductor of electricity (heat, too); it has 15x to 22x the resistance of copper.

 

Anyway, the 30A "buck" regulator I posted has an output range from 30A down, but as the current goes down, the ripple gets worse.

This may or may not be a problem.

The most difficult part of building that regulator will be the inductor; you won't likely find one pre-made at that value and current level. It will need to be a big toroidal inductor wound with AWG 10 wire or larger.

Your biggest problems right now, as I see them, are:
1) Heat dissipation in the cell itself. This has to be resolved somehow, and it is not a trivial problem.

2) Monitoring of the internal cell temperature. This is a must; you need to terminate the supply of current to the cell before the limits of safe operation are reached, [eta] depending upon what the cell construction material is.

3) Maintaining electrolyte concentration at the proper level. Since only the water gets broken down to H2 and O, once the proper electrolyte concentration is established, simply maintaining the level of water should take care of this.

 

Oh, and stainless steel is great for it's corrosion resistant properties. Unfortunately, it's a lousy conductor of electricity (heat, too); it has 15x to 22x the resistance of copper.

I've always wondered why they couldn't use the plates from a lead/acid battery for the cells. Once the acid is removed from the equation the plates shouldn't try to take a charge,just conduct it.

When GM removed the dropping/ballast resistors from their ignition systems the replaced them with 6 or 8 feet of stainless steel wire in the wiring harness from the ignition switch. I worked for 30 years at GM/Packard Electric and the made the wire and harnesses there.

 

I've always wondered why they couldn't use the plates from a lead/acid battery for the cells. Once the acid is removed from the equation the plates shouldn't try to take a charge,just conduct it.

Batteries have LEAD plates (Each plate consists of a rectangular lead grid alloyed with antimony or calcium to improve the mechanical characteristics.), HHO generators need to use (non-magnetic) stainless steel for the anode and cathode for electrolysis.....

 

HHO generators need to use (non-magnetic) stainless steel

Perhaps you mean non-corroding? What could magnetism have to do with electrolysis?

 

Perhaps you mean non-corroding? What could magnetism have to do with electrolysis?

Yeah, I've seen references to de-magnetizing stainless steel plates for use in electrolysis cells. As if it could possibly make a difference.

 

Perhaps you mean non-corroding? What could magnetism have to do with electrolysis?

There is some stainless steel that you can stick a magnet to, and some that you can not, the type that doesn't attract a magnet is referred to as "Non-Magnetic"...... It has nothing to do with electrolysis, just better corrosion resistance....

 

Yeah, I've seen references to de-magnetizing stainless steel plates for use in electrolysis cells. As if it could possibly make a difference.

 

Yeah, me too.

But, I'm trying to keep the thread serious and on-topic.

Like I said, my PWM circuit isn't perfect, but it isn't terrible, either.

It would help to reduce the size of the inductor if it would operate at a higher frequency. However, at higher frequencies, it will use up a lot more current charging/discharging the MOSFET gate.

Going to an IC current mode PWM controller would help eliminate a lot of components, but the switch (MOSFET) would still need to be external. 30A continuous current is a bit too much to ask of a commercial IC at this point.

There ARE IC's that can supply such currents for short periods, if they're properly heat sinked using large copper pour areas, but not continuously.

 

i agree with your thoughts on PVC, This is just for testing purposes.
I have been thinking about using the case from an old motorcycle battery.

I increased the concentration of my electolyte and got the following results:

2.5 amps- 9.96 volts
6.4 amps-10.00 volts
10.4 amps-10.07 volts

More thoughts on this...

The next step would be to attempt to quantify the amount of gases that are generated vs current flow.

2.5 amps- 9.96 volts; 24.9 Watts, gas quantity generated: ?
6.4 amps-10.00 volts; 64.0 Watts, gas quantity generated: ?
10.4 amps-10.07 volts; 105 Watts, gas quantity generated: ?

One inexpensive way that you might use to quantify the gas is to use clear tubing with water in it, that has a dip in the middle. As gas forms, it will start to bubble across the dip. Counting the bubbles as they pass under the dip vs time would do it.

The bubbles should all be about the same size, if the water is pure and not contaminated with surfactants or surface tension reducers like soap or detergents.

You need to vent the gases away from yourself anyway - might as well do something useful with them at the moment Besides, the dip in the clear tubing with water in it will make for a fairly good flame arrestor.

 

Batteries have LEAD plates (Each plate consists of a rectangular lead grid alloyed with antimony or calcium to improve the mechanical characteristics.), HHO generators need to use (non-magnetic) stainless steel for the anode and cathode for electrolysis.....

What does the plate material have to do with it? people only use stainless because it doesn't corrode. I'm sure that people just use stainless because thats what they thought of when their copper plates eroded when they started out experimenting with this.

It's the effect of the electrolyte and the electricity through it that forms the gasses. The lead is more conductive than stainless and just as noncorrosive if not more.

Even a lead/acid battery gives off hydrogen gas as it charges.

 

What does the plate material have to do with it? people only use stainless because it doesn't corrode. I'm sure that people just use stainless because thats what they thought of when their copper plates eroded when they started out experimenting with this.

It's the effect of the electrolyte and the electricity through it that forms the gasses. The lead is more conductive than stainless and just as noncorrosive if not more.

Even a lead/acid battery gives off hydrogen gas as it charges.

from what I have seen, they just prefer the stainless, especially in some occasion where they use KOH, and NaOH in their solution, it is more for the prevention of sulfate build up....

I could do that with a couple of pencil leads ..........

And yes batteries do give off hydrogen, that is why manufacturers recommend you charge in a well ventilated area due to gassing (Or warn of smoking near lead acid battery charging areas in risk of explosion...) ....

thats just common sense .....

 

You have all made some very good points. I'am not trying to reinvent the wheel .As of yet I have been unable to locate any worthwhile information about anyone else's test's with different plate materials.If anyone out there knows of a web site where I might find information I would greatly appreciate that info: I live in Southern Idaho close to the IDAHO NATIONAL ENGINEERING LABORATORY (INEL). I know they are doing alot of research on hydrogen cell technology,I have looked through their Website and there is alot of interesting info .
I believe I will revisit their site and see if I can pick-up any thing i missed.
Like I said before: THIS IS TO OCCUPY MY TIME DURING THE COLD WINTER NIGHTS
I have some heavy brass lugs salvaged off an old "SWITCHBOARD",I could cut some of these down ,and experiment with them (possibly add a zinc as a sacrificial element) .I have aluminun sheets available, I also have lead plates.
I know a few people who work at the (INEL),They may be able to steer me in the right direction (IF IT'S NOT CLASSIFIED).
THIS COULD BE A VERY INTERESTING WINTER.
THANKS AGAIN FOR ALL YOUR INPUT,I WILL KEEP YOU POSTED OF ANY NEW RESULTS AND/OR IDEAS JS

 

You have all made some very good points. I'am not trying to reinvent the wheel .As of yet I have been unable to locate any worthwhile information about anyone else's test's with different plate materials.

This sounds like you need to consult with a materials engineer.
Some relative electrical resistances for you (copper being 1.0):

         Silver: 0.936
         Copper: 1.0
           Gold: 1.403
         Chrome: 1.53
       Aluminum: 1.549
       Tungsten: 3.203
          Brass: 4.822
Phosphor bronze: 5.533
         Nickel: 5.533
         Nickel: 5.786
           Iron: 5.799
            Tin: 6.702
          Steel: 9.932
           Lead:12.922
Stainless steel:52.9
       Nichrome:65.1

The plusses and minuses of these various materials should be obvious just on cost basis and conductivity alone. Stainless steel, if used as a plate, will obviously dissipate a lot of power as heat.
Cost, conductivity, corrosion resistance, etc. all need to be considered.

If anyone out there knows of a web site where I might find information I would greatly appreciate that info: I live in Southern Idaho close to the IDAHO NATIONAL ENGINEERING LABORATORY (INEL). I know they are doing alot of research on hydrogen cell technology,I have looked through their Website and there is alot of interesting info.

Well, I suggest that you start looking at various materials related to their cost, conductivity, and corrosion resistance/resistance to pitting when used in electrolysis.

I have some heavy brass lugs salvaged off an old "SWITCHBOARD",I could cut some of these down ,and experiment with them (possibly add a zinc as a sacrificial element) .I have aluminun sheets available, I also have lead plates.

Brass would be a far better conductor than stainless, but is prone to corrosion.

Good luck with your research!

 

Thanks for the quick response Sarg,
As I opened this post I was looking at a similar chart in my AMERICAN ELECTRICIANS' HANDBOOK (eleventh edition) It also has temperature coefficient, and percentage conductivity. Stainless is not on my chart. Thanks Again JS

 

I have been looking at the INEL RESEARCH LIBRARY site,
It appears that most of there research has to do with High Tempurature Electrolysis.There is mention of ceramic plates,(more sights to investigate).
More thoughts:

a conductivity cell to monitor electrolyte concentration ?

high limit temperature switch manual/or automatic reset ?

water level sensor with alarm

high pressure limit switch

For the record I'am using a flashback arrestor designed for an Acetylene regulator.

 

I have been looking at the INEL RESEARCH LIBRARY site,
It appears that most of there research has to do with High Temperature Electrolysis.There is mention of ceramic plates,(more sights to investigate).

Interesting.

More thoughts:

a conductivity cell to monitor electrolyte concentration

That could be taken care of by simply monitoring the voltage across the cell(s).
When you increased the concentration of electrolyte, you started getting nearly a "brick wall" response; the voltage across the cell was barely increasing at all, even though you went from 2.5A to 10.4A, the voltage was practically constant at 10v. Many linear regulators won't perform that well.

If the voltage across the cell increased, the electrolyte concentration is too low.

high limit temperature switch manual/or automatic reset?

It needs to have hysteresis. Once it has heated to near the limit of safe operation (with a comfortable margin added), it needs to cool down until it is well within the safe zone.

water level sensor with alarm

You'll need to monitor the water levels in the partitions; two levels: "full" and "low". If the water level is not up to full, water needs to be added automatically until it is full. If the water level gets to "low", the system needs to be turned off automatically.

high pressure limit switch

I would call "high pressure" to be less than a couple of lbs per square inch. You will need some kind of safety valve to vent any excess pressure in a safe manner, through a flame arrestor.

For the record I'am using a flashback arrestor designed for an Acetylene regulator.

Keep in mind that if you are dealing with mixed oxygen and hydrogen gases, an arrestor designed for acetylene gas alone may not be sufficient to stop a flame front.

The only thing I can think of offhand that might work, would be a long sintered bronze element. However, I have no experience or qualifications in such areas of endeavor; it's little more than "a wild guess". This is not a good thing to be making wild guesses about.

 

Good feedback,
I believe I will do some controlled testing on flashback arrestor, I have read where others are using a bubbler for there arrestor (SAFE ENOUGH)???? Safe enough is (NOT GOOD ENOUGH FOR ME). I have several sintered bronze fuel filters, I can test them out to-I can try them single or in multiples. The sintered bronze would definetly be cheaper/ Safer is going to be Cheapest / I am too fond of my BODY PARTS.
I have seen batterys and gasoline cans blowup. I can just imagine the havoc that one of these things can create.

 

I believe I will do some controlled testing on flashback arrestor, I have read where others are using a bubbler for there arrestor (SAFE ENOUGH)????

I would not rely on a bubbler alone. If the bubbler should lose it's supply of fluid, you would be a loud 'kaboom!' just waiting to happen.

The idea of sintered bronze is that it has a good deal of mass that would absorb a good bit of heat, and very small passageways that would have to be heated before a flame could make it through. However, impurities (like calcium/mineral deposits from water, dirt/dust/soot from the air, etc) would tend to clog those tiny passageways - then you would have a plug rather than a vent.

Safe enough is (NOT GOOD ENOUGH FOR ME). I have several sintered bronze fuel filters, I can test them out to-I can try them single or in multiples. The sintered bronze would definetly be cheaper/ Safer is going to be Cheapest / I am too fond of my BODY PARTS.
I have seen batterys and gasoline cans blowup. I can just imagine the havoc that one of these things can create.

If an ignition source gets inside your cell, you will have a small bomb on your hands.

A loose piece of hardware (nut, screw, washer), a strand of wire, a metal shaving - just about anything causing a short across the plates will result in a hot spark. If the short occurs below the surface level of the electrolyte, you might be OK, but then again you might not.

Back on the pressure thing (related to restrictions in vent lines/bubblers/flame arrestors)
Remember that your cell box is made out of PVC plastic. That stuff can be fairly strong when it's in a tube form. Some of it is rated for 600+ PSI.

However, you've glued it together in a box. The corners are the weakest points.
If the sides are, say, 8" wide by 6" tall, then you have 6"x8"= 48 square inches of surface area, on both sides of the box.

If the pressure in the box builds to just 2PSI, then you have 48"x2PSI = 96lbs of force outwards on EACH SIDE of the box.

So, from one side to the other, you will have 192lbs of force trying to rip your 6"x8" box apart.

 

Now that the discussion has come back to the obvious dangers of dealing with a pressurized explosive, let us all recall that the electrolysis cell may easily be constructed such that the gasses are separated, and do not create an explosion hazard.

Until some brave soul can post a valid and legitimate reason for the utter necessity of introducing an explosive mixture into an engine, these threads are becoming rather unacceptable. The hydrogen gas alone can find enough atmospheric oxygen to combine with.

One speaks of using the mixed gasses as fuel in a torch. How many oxy-acetylene rigs run from just one tank? They do not, as the mixture is fantastically explosive. How is a mix of H2 & O2 not as dangerous?

I have the impression that a great majority of people who are interested in the possible savings, or increase in gas mileage, simply do not get information that is at all safety conscious. An explosion trap is not a safety item - it is a bandaid on top of a problem that never should exist. It serves to point out the utter irresponsibility of the "water power" sites. Producing a safe electrolysis cell is quite simple.

We have a policy of cutting off discussions that can cause harm to a user. I have to say that a gas explosion fits that description.