[beachy]

I was thinking to do this but I had some concern about electrolysis, as electric water tanks are designed for AC, not DC.

But I never learned if this was a real concern or not.

[opwieurposiu]

In north america both terminals of the heating element are galvanically isolated from the tank, so this is not an issue if the wiring is installed with due care.

In countries like brazil and germany that allow "bare wire" heating elements you might have trouble with the tank lining plating onto the element or visa versa.

[beachy]

Thank you! I will check the regs for my country.

[SkyPuncher]

There's a slew of DC powered electric water heaters. Relatively common on RVs and travel trailers.