Ok, so i said that i would keep you in the loop on my results. Scenario that i am using is replacing lower 240 volt water heater element in my water heater with DC current pulled off of my solar controller from the line feed when the batteries went on float mode not contributing anything to collection of solar energy.
Re-capping: I tried multiple different dc heating elements that did not work very well and will concentrate on the progression of best results.
So I did a comparison test on DC water heater elements. First tried single element 24 volt 400 watt with a dc controlled thermostat. In this first test i attempted to use energy direct from solar panels not going through the solar controller. Panels used were 305 watt , VOC 45.6 volts, ISC 8.921 amps. Tried different panel combinations in parallel and in series, best results were 3 panels wired in parallel. Using 5 gallon bucket of water, the 400 watt element heated water from 75 degrees to 145 degrees. Readings off of the element with 3 panels were 32 volts with 22 amps or 704 watts from a 400 watt element. I installed this unit first in my lower hot water heater bung. Worked great for about 4 hours and then the dc thermostat fried. Not good to push 700 watts through a 400 watt thermostat. Thermostat was still ok and working but I pulled the element thinking that it was going to fry and cause a leak to happen. Next i tried a 24 volt 900 watt single element. It took 1 hour to raise the water temp in a 5 gallon bucket of water from 75 to 125. This was ok but did not do as well as the 400 watt element. Back to the books to see what I could try next. I had someone on here mention a dual probe dc water heater element, next chapter.
Re-capping: I tried multiple different dc heating elements that did not work very well and will concentrate on the progression of best results.
So I did a comparison test on DC water heater elements. First tried single element 24 volt 400 watt with a dc controlled thermostat. In this first test i attempted to use energy direct from solar panels not going through the solar controller. Panels used were 305 watt , VOC 45.6 volts, ISC 8.921 amps. Tried different panel combinations in parallel and in series, best results were 3 panels wired in parallel. Using 5 gallon bucket of water, the 400 watt element heated water from 75 degrees to 145 degrees. Readings off of the element with 3 panels were 32 volts with 22 amps or 704 watts from a 400 watt element. I installed this unit first in my lower hot water heater bung. Worked great for about 4 hours and then the dc thermostat fried. Not good to push 700 watts through a 400 watt thermostat. Thermostat was still ok and working but I pulled the element thinking that it was going to fry and cause a leak to happen. Next i tried a 24 volt 900 watt single element. It took 1 hour to raise the water temp in a 5 gallon bucket of water from 75 to 125. This was ok but did not do as well as the 400 watt element. Back to the books to see what I could try next. I had someone on here mention a dual probe dc water heater element, next chapter.
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