i think there is something fishy going on with that coffee maker.
yes, my vaca spot is off grid, but i live, for the most part, on grid in portland, OR.
after reading all this, i'm convinced that the coffee maker would probably run fine on a 20A grid circuit. it may produce shorts up to 4000-5000w, but for VERY short times. i'd bet a grid 20A circuit would hold that just fine. i'm continually amazed in old commercial buildings where i purposefully short the hot and neutral with an old junk screwdriver, and how many sparks fly before the breaker finally flips! (gloves, and sunglasses on for these jobbies)!
but with an offgrid setup, my surge is maxed at 2900w, and i don't think it goes past that by even 100w.
in conclusion: i think chinese coffee makers are built to abuse 20A grid circuits, but not off grid inverters. i may be able to buy 15 of the identical coffee maker, and have 2 or three that work just fine with my inverter, but all the others may not.
i plan on buying a completely different brand/style next time up, and returning the one i bought the first time on my drive back home.
and yes, the coffee maker was far from ground. sitting on a wooden bench, on it's plastic feet. basically a non-issue.
adam