I just made a honey of a deal on Honda's biggest inverter 3KW genset,
the EU3000is. I was bringing my little 1KW back for warranty service
on the carb and this guy with a 5th wheel camper was unloading it onto
the tailgate of his Dodge dually diesel pickup. "How do you like the
3KW?", I asked him. He said it was fantastic but wouldn't start his
15KBtu roof A/C and he was bringing it back to this dealer to trade it
in on a camper twin Honda. I asked him how much he wanted for this
one and he thought a minute and said $1800. I started it, hell it was
brand new. "I'll give you $1500 cash within 30 minutes as soon as I
go home to get it.", I tried. "Hmm...well, that's more than they're
gonna give me on a trade. Deal!" We met at my bank to notarize the
bill of sale and get away from the dealer's salesman that looked like
he was going to kill me...(c; $1800 is the internet price. Dealer
retail is $2K with prep and ad-on taxes about $2400. Man, you can
hardly hear this little box run. SO quiet.....

Why the boat genset manufacturers don't buy Honda's technology and
make an econo-speed inverter genset is crazy. Engine speed has
nothing to do with frequency. Until the load on it get over 1200
watts, the engine stays near its low economy speed around 1000 RPM.
The 3.4 gallon tank will power a 750W load for TWENTY HOURS! With
piston speeds so low, (even at full load it's only running 2500 RPM,
not a constant 3600 RPM) it should last a lifetime. Output is
60.00007 Hz at no load and 60.0036 Hz at 3000 watts on my counter.
Output voltage varies by 8 volts from no load to 3KW. The sine looks
very clean on my scope with very little distortion, even at full load.
It's much cleaner than a Heart in a boat. And there's NO dip in power
as you jerk a hard load onto it. Must have some hefty filter caps in
the inverter's input rectifiers. The actual alternator is a 3 phase,
high voltage tiny little thing. Dry weight with the internal
fiberglass Super Quiet case inside a square steel outer case is only
130#. Two can lift it easily and there is a wheel kit for it if you
want.

http://www.hayesequipment.com/eu3000is.htm

Too bad its exhaust is impossible to weld and output dry stack to.
It's all wrapped up inside the fiberglass and cooled with the blower
in the engine. It'd make a helluva nice sailboat genset so compact.
It's noise level is less than someone talking! The cabinet doesn't
even get warm! It'd be so easy to make a boat model. Guess there
isn't a market for it.