Hi Jetijs,

Very nice cell . This is the design I'm currently building at the moment but you build it first. This design is cheap and easy to make. I'm waiting for ordered plates to arrive. There will be three different sizes so that I could make full use of the vinyl sheet. 10" x 8", 9" x 7" and 6" x 6". I may drop the idea of drilling clamping hole onto plates since you mentioned the current design able to solve electrolyte leaking problem.

In your initial post, you mentioned 33 plates. I was wondering how could you use 12V. This makes sense. Very nice expandable cell design which everybody can easy replicate.

Few questions on your design.

1. Did you drill small holes at the bottom of the plate for electrolyte auto levelling?
2. I didn't see electrode terminals in the pictures. How do you connect power to your cell?
3. You mention input power 15V and 20A. How do you measure voltage? Voltage probe across the cell terminals or source power (battery or power supply).

Few suggestions on problem you faced

1. If its true series 7 cell, optimal electrolyte strength (28% KOH and 72% distil water). Don't use teaspoon measurement for electrolyte to get exact measurement.
2. Use double layer (3mm + 3mm) vinyl to increase cell spaces. This will not elliminate the foam (cold electrolyte) climbing to top but could lower the foam climbing height.
3. Parallel series cell design should eliminate foam climbing top problem totally because of larger cell spaces.
4. Polycarbonate is not compatible with KOH but compatible with NaOH. So don't use it.
5. You need to measure the voltage across the cell and not from power source.
6. Properly conditioned cell should produce much better result.
7. Measure gas output after the electrolyte warmed up to get correct measurement.

For your info, your first test using 15V and 20A for 2L per 90 seconds, your cell efficiency is at 62.71%.

Second test using 13.5V and 20A for 2L per 80 seconds, your cell efficiency is at 78.39%.

I can send you the MS excel sheet to calculate the cell efficiency and keep a clean record of your progress. You just need to input appropriate value like above and the program will calculate the efficiency.

Just PM me your email address if you need it.