Water heater modification to use solar and electricity

Mike Haasl wrote:Thanks Jordan, I plugged it into the MidNite Solar site and it gives a VOC at -30C of 76.7V.

That sucks, too bad I bought those, I hope my buddy knew what he was getting (he bought a bunch).

I'll have to dig into the thermostat issue some more to see if there's a higher voltage option out there.....

Alright mike hopefully the polish beer I am drinking hasn't messed this up.

So I found a 100V DC Relay which is controlled by 12vDC https://canada.newark.com/c/switches-relays/relays/solid-state-relays-contactors/solid-state-relays?load-current=20a&operating-voltage-max=100vdc
I believe you could control the relay using something like this https://www.hurricanewindpower.com/thermostat-for-dc-water-heater-element-140-degrees-fahrenheit-water-overheat/

The 12vdc thermostat would need to be powered by a battery or a power supply... Or a battery which is continuously being charged.

I would set the panels up in parallel.  You had said 54 feet. Which at say 60VDC(12amps) using 10awg wire. the voltage loss is minimal. around 2.5% voltage drop.

so yea, the relay will be a cost. It will most likely need a heat sink. The solid state relay I just installed required one. I made it myself instead of buying one(scrounged).

It would be wise to put a circuit breaker of say 15amps in there. Along with an appropriate fuse for the 12vdc circuit. I didn't seem to find any affordable 100VDC relays at 15amps. 100vdc 20 amp SSR seemed to be more common.