We had 300 watts of
solar, and a 500 watt
wind gen. We also had a 1000 watt
generator and a high output
alternator. Our
battery bank was 440 as one
battery died. So a 27 inch imac on an
inverter will draw anywhere from 12 to 20 amps depending on how much you dim the
screen.
On windy days we had no problem, and in cooler climates the sunny days were great. Otherwise I would say it is not practical. A 12 volt flat
screen the same size might draw 3 or 4 amps.