Excess solar dc to water heater

[natbarre]

Hello all!
I keep my vessel here in San Diego on a mooring ball and have too many solar panels! I have 900W installed and my batteries are nearly always topped off. I'd like to divert the excess wattage to my water heater.

I currently have an old water heater that has a heat exchanger input connected to my port volvo diesel and am open to replacing it with a new unit or at at least shoving a 12v heating element in it (though ideally I'd preserve my 110v heating capability)

I found this guy's method with a 12v silicone heating pad, but he has a complicated load diverter setup and I'd love something a bit simpler. Perhaps something utilizing an ACR? Perhaps a simple programmable switch?
https://youtu.be/_u0URusLxnk

Does anyone have any experience with this?

 

[DavidM]

Usually boaters have too few watts of panels, not your situation with excess. A simple way is to install a 110V heating element in your water heater. You can often just screw one in in place of the drain plug. Then use an inverter to convert your excess DC to AC for the water heater.

David

 

[socalrider]

Hi! I did this and am currently in Catalina enjoying hot showers.

I used a 12V element (you also need a 12v thermostat) and relay with a dump load controller from Missouri Wind and Solar: https://windandsolar.com/

I posted a thread about it if you search it up. It’s working great. I have the controller set to turn the relay to the element on when it’s switched on or when voltage gets to 14.4V, then off when voltage drops to 12.3V - seems to work perfectly. Solar charges my batteries almost to full first, then starts dumping to the heater.

 

[backinblue]

I hate you people in southern CA whos biggest problem is too much sun! Just kidding of course but had to respond. I wish my biggest boating concern is what to do with all this excess energey! LOL

 

[socalrider]

I hate you people in southern CA whos biggest problem is too much sun! Just kidding of course but had to respond. I wish my biggest boating concern is what to do with all this excess energey! LOL

Hey it’s not all roses out here. In December we have fewer hours of sun and sometimes it rains. Plus you need a wetsuit to go snorkeling. So it gets tough out here too!