need help sizing dc water heating
- Thread starter xboxman99
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orangezero
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- Sep 20, 2020
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I'm no expert on this (pardon my terms), but I believe the correct answer would be to focus on the ohms. There are many youtube videos I think that try and fail to really explain this in a simple way. In this case with resistance heating (no inductive motor, etc), AC and DC operate essentially the same. The issue is, basically, that the water heater AC element is probably "tuned" to run with 110v or 220v, while you would get around 36v or around 72v with those two panels. The element could give you around the correct wattage at 110v, but if you cut that voltage the power goes down more than you may suspect.
Someone correct me, but I believe with what you have your best case would be (72 x 72) and then divided by the ohms to get you the current that will run through the element. So, a heating element of say, 200w, tuned for 110v will produce very little power when run with 36v, and not a ton with 72v either.
So your goal should be to lower the resistance somehow. Occasionally the elements have multiple screw terminals so you can run the element itself in series or parallel to adjust the ohms but you may still need to purchase a new one.
Someone correct me, but I believe with what you have your best case would be (72 x 72) and then divided by the ohms to get you the current that will run through the element. So, a heating element of say, 200w, tuned for 110v will produce very little power when run with 36v, and not a ton with 72v either.
So your goal should be to lower the resistance somehow. Occasionally the elements have multiple screw terminals so you can run the element itself in series or parallel to adjust the ohms but you may still need to purchase a new one.
Whats-n-Watts
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The largest true DC element I can find is 48v 1500 watt. Will you using a battery with it?
Whats-n-Watts
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Water Heating Calculator for Time, Energy, and Power
The calculators on this page compute how long it takes to heat water, how much energy is consumed, and how much heating power is required.
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