I'm in the process of researching and designing a small RO desalinator
for my Sea Sprite 34. Have found Glenn's, GOB's and other DIY articles
to be good resources. However, my engine compartment will not easily
accommodate a CAT 277 sized engine driven pump. Also don't have room
(or $$) for a large built-in generator to deal with the startup
requirements of a 2HP electric motor. I already have a Honda eu2000
generator which, based on it's output, will be used to size the
smaller watermaker. With 2000W max and 1600W continuous on the eu2000,
it looks like the largest electric motor possible is a 3/4HP. A 1HP
may be possible with soft-start electronics, but I haven't been able to
find reliable information on the subject (even from Baldor). The 3/4HP
motor would directly drive a CAT pump model 2SF10SEEL (1 GPM, 100-1200
PSI, 1725 RPM). Fitted to a 2.5 x 14 membrane, it should provide 100GPD
(about 4GPH).

I'm still trying to find other ways to increase the system's capacity.
There are 3/4HP motors available that run at twice the RPM (3450),
which could be "geared down" with a pulley/belt to drive a larger
capacity CAT pump at the required 1750 RPM.

Using the eu2000 generator as a power source for watermaking has
obvious downsides: noise, long run times & low product output. There
are two of us, so our water usage would usually be small and our total
tankage is only 90 gallons. A couple questions to the group: do my
3/4HP system components and output assumptions look right and are there
any other options available for increasing the capacity of the
watermaker within the generator's power constraints?

Will

"Twilliam" wrote in
oups.com:

With 2000W max and 1600W continuous on the eu2000,
it looks like the largest electric motor possible is a 3/4HP.

I use the bigger EU3000is in my mobile shop. It's starting two 8000 BTU
window AC units and a 4.2 cuft bar fridge simultaneously just fine, most of
the time. Sometimes the window ACs compressors get locked, somehow, and it
trips the overload IC if it doesn't start in a few seconds. I start it by
itself and everything is fine.

I started out with the EU1000i which ran one 6000 BTU AC fine but I needed
more power for more AC to keep it cool in the 100F heat of SC in August.
The twin 8000's keep it cool even at mid day in the sun. I can drop one
offline to save fuel in Spring and Fall or evenings, which is nice.

I had some trouble with the little engine in the 1000i. The Honda dealer's
motorcycle mechanics seemed puzzled, so I took it to a small engine shop
that offered to fix it. They found the exhaust valve wasn't closing all
the way and replaced it. Runs great, now, but the 3000i runs MUCH slower
(1200 RPM pulling both ACs and fridge after initial starting on Econo
mode). Don't hesitate to upgrade to the 3000is. It's a much better genset
than the suitcase models. Mine has about 900 hours on it now....even on
the same spark plug.

--
Larry

If I only had room for a 3000, it would solve two dilemas. We are
northbound in the Chesapeake. Can't believe the heat. A big air
conditioner would be heaven!!

Will