I noticed some calculations seemed to be off when looking at my data spreadsheet, and realize that some numbers could be off due to a ‘margin of error’ in the equipment, so reran some of the tests to verify the results, and got the same numbers.
The results showed that when doubling the plates the amps and output were not quite doubled, tripled, etc as one would have thought. Then I spotted a possible flaw in plate surface calculation, then a second flaw and figured I pass them on, since the numbers now come out within 2% when doubling and tripling surface area.
First lets start with a 2 x 5 in plate, 10 sq in surface area. Sort of, I punched 2 – 1/4″ holes in each, pi*r*r = area of circle, so the two holes remove 0.3925″, leaving 9.6075 sq in., so remove any holes or slots that may have been cut or drilled into the plates.
Second there are 2 sides to the plate in contact with the water, sort of, take 2 plates, one +, one -, only one side of each is producing gas, the other 2 do nothing. So if you have 10 plates, effectively only both sides of 9 plates are in contact, so multiply number of plates-1, by 2, by area of plate, so 10 of these plates are 86.4675 sq in not 96.075 producing gas. A large difference when thinking there would be 100 sq in with 10 plates of 2×5.
This minor difference added at least 14% difference in numbers collected, the 2% error so far I think I can attribute to the surface of the hole on the edge (inside the holes) and possibly the edges of the plates when submerged.
Now when I’m producing 300ml with 5 plates @ 3 amps, and then double them to 9 plates and I get 600ml @ 6 amps, the numbers even work out. And before you say 5*2 is 10, not in this case, 5 plates have 4 working pairs, 9 plates have 8 working pairs, so yes 5*2=9 in this case.
Hope this helps when calculating a new HFE cell construction to get more accurate results.
Filed under: Cell Type, Output testing
Were the figures you used a random example? I consider 100ml/amp the bar we are trying to get over (specifically one liter per minute at no more than 10 amps).
BTW, I’m currently working on a long cell (12″), with .020 spacing, and forced water movement through the cell.
Clickster,
those are figures from a cell I’m working with currently, plate size has been changed for easy calculation in the example, amps and output are real.
A question I have is the spacing your using, I had been held to .040 and .050 till now, now I can go to .030, have you seen an output increase at the smaller spacing?
I’m also now keeping track of fluid temp increase during run time, for instance, I run the cell for 2 hrs, repeatedly testing output, and measuring temp increase, my cell raises about 1 deg/min till it hit 130, then tapers off till it reaches 140, then stabilizes there. Starting with 72 deg, it takes about 60 min to hit 130, then another 20 min till 140. The output only increase about 50ml from 70 to 140 deg. So I’m saying it has a 1 deg/min max heat increase @ 6 amps and 50ml increase in output. The increase in temp explains where the loss in efficiency is occurring, and how much.
Dave,
Yes, production when up but so did amps. That is why I’m so intrested in your ml/amp ratio. I’ve seen your data on different plate configurations but what did you settle on?
I’ve experimented with spacing as little as .012 but I believe that the gas displaces enough water that it hurts production. That is why I’m going to force the water through the cell and see if that helps.
I settled on a +NNNN-NNNN+ setup when using brute force and catalyst in my dry cell.
But for the PWM and plain water a +-+-+-+- draws 6a, with a 9a initial surge, using .030 seals. Unfortunately I wasn’t able to check output due to a stupid mistake with the hoses and a soldering iron.
Where can I find
drawings
parts list
specifications
I want to make a HHO cell and I think your site will help me.
Thank you for your help
Jack