Bruce in Bangkok wrote in
news
Suggestions: Think that Stephen is right. Seems senseless to run 12VDC
through inverter to power 220 VAC compressor. Always some losses in
this type of system. Believe that air cooled condenser makes more
sense as personal experience shows that 12 VDC air cooled system works
in tropical climate and eliminates all the problems associated with
the water cooling system - pumps, clogging, etc.



Does someone make a 12VDC compressor? I've never seen one, here. I do see
AC inverters built into fridges driving standard AC-powered compressors
that have relays or electronics to switch to shore power if shore power is
available to run the compressor straight off shore power, however.

Inversion and synthsized AC power creation from battery power is now in the
range of 98-99% efficient with switching power supply technology using
pulse-width-modulation to accomplish a near-perfect sinewave output to
drive loads. These powerful synthesizers are very cheaply constructed and
very profitable.

The AC compressors synchronize to power line frequency (50 or 60 Hz), which
gives them a steady power output regardless of condensor pressure loading
which would drive a DC motor crazy trying to maintain counter EMF.

It makes little difference in efficiency running a switching inverter
outside......or building one inside for another $1500 to sell at the boat
store. The price difference is phenomenal!