Ok,
I increased the electrolyte concentration to the max. This made the max amps (20A) flow through the five 6-cell compartments at 13.5V. I measured the gas ouput and this time I could get 2 litres in just 1minute and 20 seconds. This is great, I reduced the power consumption by 30W and slightly improved the gas production just by increasing the KOH concentration. Also I just remembered one more advantage of this design - there is very small volume of gas inside the cell, that means that less damage can occur if the bubbler malfunctions, also you can't really break anything, because the explosion would probably just squeeze the nylon spacers out leaving the plates in tact Maybe the plexiglas end plates would crack, but that is not a big deal since you can easily and fast make new ones. I am considering using different electrolyte and switch the endplate material to polycarbonate, in this case even the end plates would not crack in a event of explosion
Thanks,
Jetijs.