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dg2010
05-23-2010, 12:23 PM
Wonder if someone can help me with my falling gas production.

Firstly the cell details
Construction is 316
Cell layout -5N+5N-
Exposed plate area is 5 1/8" square
Alternate 1/2" holes at the bottom
3/8" holes top centre in line
3mm nitrile gaskets

When I bench tested this with a friend using a PWM it produced 3lt/min at 14v and 20 amps. 28% concentrate KOH.

Put it into my car without a PWM and reduced the concentrate to around 15% - maybe a bit more. It pulled 20 amps like this and just assume it would produce the same.

Last week I tried to install a PWM but first did a bottle test to see where I was and found it was only producing a litre in 45 secs so didn't bother with fitting a PWM.

Yesterday I was doing some more testing and found that it has now dropped to 1 litre in 55 secs. This was after some 60 miles during last week.

I am puzzled - would welcome some advice
plasma
05-23-2010, 02:43 PM
Sorry I can't answer your question but 3lpm at 14v and 20A (280watts) gives an mmw of 10.7!? Correct me if I'm wrong but isn't the maximum mmw possible about 9.3 this means your cell was over 100% efficient!
dg2010
05-23-2010, 05:08 PM
Sorry I can't answer your question but 3lpm at 14v and 20A (280watts) gives an mmw of 10.7!? Correct me if I'm wrong but isn't the maximum mmw possible about 9.3 this means your cell was over 100% efficient!

Not sure about that, but I would guess that since it is basically two cells you would divide that in half giving around 5.3.
rcflyn
05-23-2010, 08:46 PM
I'm not sure on the MAX possible MMW Either, but I saw a 10.71 also, which, I don't think anyone has achieved. So I ran some more numbers, and find that the other 2 sets of numbers SEEM more realistic to begin with. the 45 seconds yeilds an MMW of 4.76, The 55 seconds yeilds an MMW of 3.9. Those numbers are more along the lines that most of us that I've seen, are realistically getting.

HOWEVER, If my calculations are right, you're running a current density of 1.95amp PER SQUARE INCH. WAY too much there.

I'm not sure about the Dividing Numbers in half, But I DO Know, with a 2 stack, the 20 amps your sending it gets divided in half per stack. One Stack sees 10, the other sees 10, the voltage will remain the same between the two, and I assume the MMW will be a result of BOTH, the MMW don't get divided.

If I'm wrong somewhere here, I"m sure someone will point it out for us.