Excess Power Dump Into Water Heater

[Renewable Ray]

I was wondering if any members here are heating a water heater by dumping excess power from their DIY 12 volt systems into a small 110 volt water heater?

Any info would be welcome, thanks in advance for your help!

[Mike90250]

12V, feeding a 1,000 120V heater element, will consume only 8 amps, or about 100watts, give or take. Lower than design voltage, there may be a bit of extra current, as the element will never get to design temp, and metals running cooler, have a bit less resistance. (think in-rush current with a cold light bulb filament)

[Renewable Ray]

Thanks Mike. I know guys are doing this, as much to prevent overcharge as heating the water. I just don't know how. Can you accomplish it with any charge controller?

[Mike90250]

Can you accomplish it with any charge controller?

Solar controllers don't need a dump load, hydro and wind need a load to keep the turbine from overspeed.

Many controllers can manage dump loads. You have to specifically look for it. Many "solar" controllers do not support it, as it's not a function needed by solar. Most of the Trace C series supports it. Others, I don't know about.

[henry wilson]

Yes, I agree with mike. Many devices can manage the dump load. Thanks for sharing with us.

[BilljustBill]

Mike,
I can see using another electric water heater to either heat or preheat water to use or go into the home water heater. What are you saying to do? Using a smaller 30 gallon or less water heater with all it compactness and foam insulation, but change out the heating elements? What voltage and where do you get them?
Thanks,
Bill

[sunnyjim]

12 volt water heater elements

Here are some links to businesses that sell 12 volt water heater elements in various amperages.

http://www.missouriwindandsolar.com/Water_Heater_Elements.html

http://www.hydrogenappliances.com/hotwater.html

Has anyone experimented with any of these? Why not use some PV to directly run a 12 volt water heater element or two?