Quote:
Originally Posted by Jetijs
Could you tell me more about the acurate power consumption measuring? I don't get it. I mean what is the difference? My variable power supply has 20A max outpu, when it senses that the load has too small resistance, it decreases the voltage to keep the amps at constant max setting. This is how I got the 13.5V 20A. I mean watts are watts  Am I missing something here? |
Yes you are missing some very important point in measuring voltage and amperage. Trust me. I did the same mistake during my initial testing on motor generator project. Somebody identify the power measuring mistakes.
The voltage that shown at power supply is source voltage. Source voltage is always higher than load voltage. You can use amperage readings from power supply since the amperage is in series. If we measure amperage reading anywhere in the circuit, its still the same. But voltage would be different. We are only interested in load power consumption. I give you another example which can clear some confusion here.
Power source : Battery 12V 70AH
Load : Car head light bulb
Before connecting the above circuit, just measure the voltage across battery terminal. Let say 12.8V before load. Now connect head lamp in series with amperage meter (if you have one). When circuit is complete the amperage reading should show some readings like 7A. 7A is amount of current consumed by load (bulb) and tiny resistance from wire used for connecting load.
Now, measure again voltage across battery terminal. The voltage should reduced somewhere 12.5V depends on load power consumption. This is the voltage shown on your power supply meter.
To get load voltage, just measure voltage across load. You should see less voltage than 12.5V. Let say 12.3V. So the power consumption for load (bulb) is 12.3V x 7A = 86.1 watt. We are only interested in load power consumption and forget about source power output.
I believe, your cell should perform much better than my cell. Wild guess 120% or more since its true series cell.
Quote:
Originally Posted by Jetijs
Also, how can I dose the electrolyte concentration? I have the KOH in a form of white flakes. Do I weight these flakes?
Should I sand blast the plates to increase the surface area?
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Yes, the percentage for KOH and distil water is measured by weight ratio. For my cell, I use 300 gram of KOH and 1200 gram of RO water. 20% KOH and 80% water. Cross hatch the plates surface with rough grit sand paper. Bob Boyce did advice not to use sand blast method to increase surface area. More important is conditioning the plate which will take weeks. Properly conditioned plates could produce much higher gas output (> 50% or more).