by resident_genius » Sun Feb 22, 2009 1:09 am
those are light switch plates, a conservative measurement is 2" by 4".... two positives, two negatives.... positive comes in the middle two plates, and has two outer negavies connected by a strap.
so essentially, i've got 32 sq in of surface area per cell. i didnt measure how much KOH, i'd imagine i put in about 4-5teaspoons. per two liters of water to that. whats interesting to note is that the amperage is dependent upon the voltage. however, if you get your electrodes very close together, and make them very large, it will draw more amps for a given voltage. so if i had two cells,
one was ten inches by ten inches, put them 1/8" apart, put 12 DCV to them, and pulled thirty amps, and had another cell, two inches by two inches, 1/8" apart, and put 12 DCV to them, the amperage would be much much less. in order to pull thirty amps with the smaller cell, it'd take more voltage.
i found that with these cells, putting 5.0DCV to them pulled 25 amps with a strong solution. the solution that i call strong can splash onto my skin, and it wont even start to itch for about five minutes. because my cells are pretty fairly matched, and built pretty identically, figured out the point at which a negligibly higher DCV caused a jump in amperage and production: it was what i call the "breaking point". so i calculated the amperage i wanted to use, and a convenient number came up: 12. 12 *2 is 24 amps, and my power supply is limited to 25 amps. perfect!
so mos, that's my real world advice. not saying that some formula doesnt work, i just take as many variables out of the equation as possible, then try adjusting each plane until i get optimal results.