I was working on a boat with two 75 watt solar panels. The owner was unsure whether or not they were developing rated power. He was using a charge controller and approximately 2.5 amps were being driven into the batteries. I needed a load that would test the output of the two panels. They were 12 volt panels developing 19 volts open circuit...........what to do?
Back in the old days we would test the ships main generators by using a saltwater test. Basically a large tank with electrodes and filled with sea water. (We made a great deal of caustic soda). I used two pieces of copper tubing immersed in a vinegar solution. I made the tubes with adjustable distances to vary the resistance. A fully charged Ryoby battery provided the "calibration" voltage.
Cheap, quick and effective, who could ask for more? As H2 is generated and coats the electrode increasing the resistance, you must reversed the connections periodically. (LEO the lion says GER)
Back in the old days we would test the ships main generators by using a saltwater test. Basically a large tank with electrodes and filled with sea water. (We made a great deal of caustic soda). I used two pieces of copper tubing immersed in a vinegar solution. I made the tubes with adjustable distances to vary the resistance. A fully charged Ryoby battery provided the "calibration" voltage.
Cheap, quick and effective, who could ask for more? As H2 is generated and coats the electrode increasing the resistance, you must reversed the connections periodically. (LEO the lion says GER)