Scotty wrote:
You don't heat off the batteries, do you? I figure the temp
needs to get high off the engine because once you shut down
it needs to stay hot on it's own for a while. Mine stays
warm overnight, at least.

It should stay hot for 24 hours, but as it turns out, the Seaward is
not particularly good. The PS review came out a month after mine was
"sealed in" - there were several that were quite hot the next day.

Running the engine without load does heat it up, but not much. Mine
doesn't get over 150 degrees unless were really running hard under
load - then its goes up to 165. Fortunately, we don't need much hot
water in the summer.

I don't think I would ever consider running off the batteries - They
would be so depleted enough I'd have to then run the engine, so why
not do both at the same time.