DC Water Heating Elements


It requires 2.47 watts to heat one gallon of water by one degree in one hour.

Real World Examples

We get asked all the time about DC water heating either with just the use of solar panels or solar panels with the use of a battery. People want to keep stock tanks from freezing or convert their AC water heater to a DC model. That’s achievable, it’s just about managing the expectation of how many watts it’ll really take to heat the water.

Examples Using Different Size Panels and DC Water Heating Elements

In the winter, when most people want to put a DC water heating element to use, you’re looking at 5-6 peak hours of sunlight in a single day. You’ll have low-light hours for power production, too, but you can’t estimate a half day of full sun in most areas. So, what does this mean? Let’s put together a real-world scenario of what solar and DC elements are capable of.

In the examples below, we will use two 100 watt solar panels (200 watts total) and one 12 volt, 200 watt DC water heating element.*

VolumeStarting Temperature (degrees F)Ending Temperature (degrees F)
5 Gallon Bucket60°120°
10 Gallon Tank60°95°
100 Gallon Tank60°61.25°

Here are some real-world examples of what one 260-watt solar panel and one 24-volt, 600-watt DC water heating element .*

VolumeStarting Temperature (degrees F)Ending Temperature (degrees F)
5 Gallon Bucket60°150°
10 Gallon Tank60°125°
100 Gallon Tank60°62.5°

Here are some real-world examples of what two 260-watt solar panels and one 48-volt, 700-watt DC water heating element .*

VolumeStarting Temperature (degrees F)Ending Temperature (degrees F)
5 Gallon Bucket60°235°
10 Gallon Tank60°155°
100 Gallon Tank60°6

* This is with an air temperature that is average of 60 degrees. You will achieve higher temperatures with a starting temperature above 60 degrees and will not achieve the temperatures stated above at lower than 60-degree temperatures.

Example: if the ambient air temperature was 33 degrees, it will make your water temperature fall as well to the point of 33 degrees. It would cause the 100-gallon tank to see barely any perceptible heating results due to this fact.

Not to despair, however. If you have a large stock tank, you’ll simply require more panels and multiple elements per tank and potentially the addition of a battery or batteries to keep things from freezing. If the volume of water is significant, 100 gallons and more, and you have extremely frigid temperatures, you might consider the addition or alternate option of aeration!

Where should you position the water heating element?

Water heating element position is just as important in getting the result you want as the correct number of solar panels!

Keep it near the top! Unlike a conventional water heater, you’ll want to position the water heating element close enough to the top to keep a hole melted through the ice. Do not position it so high where the livestock will drain the water level below the element or it will burn out. Position it too low and you may never see the positive effects where you need it.

Looking for a DC Water Heating Element?

We offer four styles in different voltages and wattages.