I am rather a Newbie at HHO.
I bought of stack of ten 316 plates off ebay and started to tinker around with them.

I can connect them in parallel with 12 volt across each plate or in series with only 2 volts across each plate. (I leave out some of the plates for the series experiment.) I immerse the plates in a beaker of distilled water with some baking soda stirred in.

I have not measured the flow rate of gas output or current draw for the two different configurations. In theory, breakdown voltage of water is about 2 volts so one would think that once you get to the breakdown voltage, anything beyond that would go to waste.

However, when I try the two configurations, I get a vigorous froth from the 12 volt but an anemic fizz from the 2 volt. Apparently, the 2 volt stack has a much higher electrical resistance. I have a digital multimeter but I did not think of using it to measure electrical resistance of different plate stack configurations.

Is there data of the electric resistance and conversion efficiency of sample stacks as a function of temperature, electrolyte concentration, plate configuration, etc?