Nickel Cell tests and questions

[astrocady]

Overview

I got seven 6x6 nickel plates from Shane the end of last week (thanks!). I put them into a very simple and basic dry cell with 5 bipolar plates, 1/4" hole on bottom in center of plates and 3/8" hole on top in center of plates. Plates are separated by 1/8" neoprene gaskets I cut by hand. I cut of the top right corner of each bipolar plates, and drilled a 1/4" hole in the top right corner of the anode and cathode to attach power cables. No heroics were done to control current leakage.

My hopes for this experiment were two fold: Eliminate all hex-chrome issues (have a potential client very concerned about this) and also to reduce the cell size while keeping production and heat buildup the same or better than my existing ss cells.

[astrocady]

First Tests

I've got the cell running late yesterday morning. I'm running 28" KOH (specific gravity 1.25 at room temp) and I'm using a 150 amp PWM fed by a battery connected to a 50 amp HD battery charger.

The first thing I noticed was that it wouldn't drawing much current. I have the PWM turned up all the way and I still had to raise the battery voltage 15 volts to get only 20 amp draw! This really puzzles me. With one of my 8x10 seven plate SS cells with that strong of KOH I could easily pull 60 amps -- but not for long, of course ;) If I hook up my second battery charger and bring the voltage up to 16 or so, the amperage will climb right up. Does the gap voltage need to by higher with Nickel plates? Do I need to removed a bipolar, and if so, won't that raise the temps?

As far as temps, at the electrolyte temperature seems to top out at about 160 degrees after 3 hours of operation then stays right there. 160 seems a little hot to me, but I'm not really sure where it should run with Nickel. What do y'all think?

Production is uninspiring at about 1.25 lpm -- still not bad for a 6x6 cell.

All thoughts, comments, advice and inspiration greatly appreciated!

Steve

[H2OPWR]

First Tests

I've got the cell running late yesterday morning. I'm running 28" KOH (specific gravity 1.25 at room temp) and I'm using a 150 amp PWM fed by a battery connected to a 50 amp HD battery charger.

The first thing I noticed was that it wouldn't drawing much current. I have the PWM turned up all the way and I still had to raise the battery voltage 15 volts to get only 20 amp draw! This really puzzles me. With one of my 8x10 seven plate SS cells with that strong of KOH I could easily pull 60 amps -- but not for long, of course ;) If I hook up my second battery charger and bring the voltage up to 16 or so, the amperage will climb right up. Does the gap voltage need to by higher with Nickel plates? Do I need to removed a bipolar, and if so, won't that raise the temps?

As far as temps, at the electrolyte temperature seems to top out at about 160 degrees after 3 hours of operation then stays right there. 160 seems a little hot to me, but I'm not really sure where it should run with Nickel. What do y'all think?

Production is uninspiring at about 1.25 lpm -- still not bad for a 6x6 cell.

All thoughts, comments, advice and inspiration greatly appreciated!

Steve

Steve, Those numbers are very puzzling to me. With my Nickel cells I have never been able to get even 2.1 volts per plate gap because the amp draw would overwhelm my Variac. I was using a 1/4" gap and 28% KOH. With your gap the amp draw should be quite a bit more as long as your cell is staying full of electrolite. I did have my plates media blasted for a very rough surface. Aside from that there should be very little difference. Nickel will run with a lower voltage per gap due to the lower electrical resistance as compared to Stainless. I have found Nickel superior to Stainless in every way with the one exception and that is the price.

My best guess is that your electrolite level especially in the center of the cell is dropping quite a bit causing the low amp draw.

Larry

[astrocady]

Steve, Those numbers are very puzzling to me. With my Nickel cells I have never been able to get even 2.1 volts per plate gap because the amp draw would overwhelm my Variac. I was using a 1/4" gap and 28% KOH. With your gap the amp draw should be quite a bit more as long as your cell is staying full of electrolite. I did have my plates media blasted for a very rough surface. Aside from that there should be very little difference. Nickel will run with a lower voltage per gap due to the lower electrical resistance as compared to Stainless. I have found Nickel superior to Stainless in every way with the one exception and that is the price.

My best guess is that your electrolite level especially in the center of the cell is dropping quite a bit causing the low amp draw.

Larry

hmmmm....

Stranger and stranger. I see you point about electrolyte level, but if that was true, I would think the amp draw would start high for a few seconds then drop off as the electrolyte is displaced by the HHO gas. Mine does the opposite. When I first turn in on, the amp draw is only about 10, then climbs to 20 where the PWM starts throttling back to hold it there. Takes about 30 seconds to reach the 20 amps.

I just went back and took some measurements. I turned the PWM all the way up. Amp reading was 23. Voltage at battery was 15.1. Voltage at cell terminals was 14.3. Voltage at cell gaps varied between 2.3 and 2.4. System hasn't been running long -- electrolyte temp at 115F. Rechecked specific gravity which was a little above 1.3 at that temp.

I have one 3/8" hose feeding the bottom of the cell, and two 3/8 hoses exiting the top. I was just checking the cell endplate temp with my ir thermometer, and was surprise to see that on the bottom of the cell, I can tell exactly where the gasket line is -- sharp drop of temp below that, with a gradual rise in temp as I go up. Highest temp is at bottom of top fitting. If I go above fitting is see a gradual drop until I once again hit the gasket line. Inlet and outlet holes are about 3/8" from the gasket.

I forgot to mention that I did cross sand my plates on my belt sander.

hmmm.

PS -- what about electrolyte temp? Where should be

[H2OPWR]

hmmmm....

Stranger and stranger. I see you point about electrolyte level, but if that was true, I would think the amp draw would start high for a few seconds then drop off as the electrolyte is displaced by the HHO gas. Mine does the opposite. When I first turn in on, the amp draw is only about 10, then climbs to 20 where the PWM starts throttling back to hold it there. Takes about 30 seconds to reach the 20 amps.

I just went back and took some measurements. I turned the PWM all the way up. Amp reading was 23. Voltage at battery was 15.1. Voltage at cell terminals was 14.3. Voltage at cell gaps varied between 2.3 and 2.4. System hasn't been running long -- electrolyte temp at 115F. Rechecked specific gravity which was a little above 1.3 at that temp.

I have one 3/8" hose feeding the bottom of the cell, and two 3/8 hoses exiting the top. I was just checking the cell endplate temp with my ir thermometer, and was surprise to see that on the bottom of the cell, I can tell exactly where the gasket line is -- sharp drop of temp below that, with a gradual rise in temp as I go up. Highest temp is at bottom of top fitting. If I go above fitting is see a gradual drop until I once again hit the gasket line. Inlet and outlet holes are about 3/8" from the gasket.

I forgot to mention that I did cross sand my plates on my belt sander.

hmmm.

PS -- what about electrolyte temp? Where should be

Steve, Really if you are getting 23 amps with that small cell then you are really putting alot of power to it. If your gaskets are even 1/2" wide then you have only 25 sq inches or less of available surface area per plate and only one 5n stack. That is gobs of power. I was running 2 stacks and my plates were 6"x8". At a constant 80 amps at 1.9 to 2 volts per plate gap the cell would max out at about 140 degrees. I had to really push it to get it hotter than that. The difference is that I was running Teflon gaskets and shims set up to block current leakage and trying for high temps. I was also running 30 psi or higher in the cell.

Unlike most others I like a hot cell. I have found the effeciency to improve with high temps and cell pressure. Getting the gas cooled down and the moisture out of it is easy if you are just playing on the bench. It sounds like you are building one for an automotive application so I would avoid those high temps. It is hard to keep your gaskets alive and even harder to keep the KOH laden moisture out of the engine when running a hot cell. I would try and keep the e-lite temp below 120 degrees for your application. I think that is the diggest difference between my work and almost everyone else on this forum. I am just researching ways to improve effeciency while most others are looking for real world automotive application. I wish my cell was closer to what everyone else is trying with Nickel but it is really apples and oranges.

Larry

[astrocady]

Your probably right, Larry, about the apples and oranges. I got excited by your bench tests and was hoping to get the same kind of numbers in the real world. 30 psi pressure bouncing down the road at 70 mph isn't something I want to try -- LOL.

I'm still a little puzzled about why I can't pull more amps, not that I need to with that size cell, you are right. But, I have some old similar sized ss cells here and with a strong koh solution I can pull enough amps to melt them if I wanted to.

I think I'll take the cell down and do a few things to control current leakage and see what that does. Will also probably try taking one bipolar plate out first, as a separate test. Will keep everyone posted, and as always, thanks so much for your input.

Steve

[astrocady]

more and more corn-fused

I took one plate of the cell. It now has a total of 6 plates, 4 of which are bipolar.

With 7 plates the cell would only draw 21 amps with the PWM turned all the way up.

With 6 plates the cell will draw 33 amps with the PWM turned all the way up -- about as expected.

With 7 plates and 20 amps, the cell heated up to a little over 160 degrees. With only 6 plates, and the PWM set for 20 amps, the cell tops out at 140 degrees. This was a surprise. I figured with one less plate, it would run hotter, not cooler.

With 7 plates at 20 amps it took 47 seconds to fill a 1 liter bottle. With 6 plates at 20 amps it took 56 seconds to fill the same bottle. This was also a surprise, as I thought with a higher gap voltage I might even see more HHO production.

On all of my SS cells, be they 7 or 13 plates, I get about 1 liter of HHO for every 14 amps -- i.e 28 amps = 2 lpm, 42 amps = 3 liters, 14 amps = 1 lpm. This is at 13.5 - 14 volts.

This 7 plate nickel cell took 16 amps to make 1 lpm, while the 6 plate version took 18 amps to make 1 lpm.

[keiththevp]

Anymore results from your nickel testing? I was looking at making a nickel cell and this makes me unsure...

[astrocady]

It's been just sitting on the table as I've been busy with other, paying, projects. I keep think "next week," and soon that day will come.

My next step is to take is clear down again and rebuild it exactly like I do my ss reactors -- no short cuts -- and see what happens. I've not given up on nickel, just no longer looking at it as a "magic bullet" to fix everything.