Low Voltage DC Air Conditioning

[Tom Wood]

I would like to install a 12-volt DC air conditioner on my boat, but I can’t find one. Can you help?

Arthur.

Tom Wood responds:

I have queried several experts in the field and no one seems to have any knowledge of a low-voltage DC air conditioning. Refrigeration and A/C units usually consume huge amounts of power that would require massive battery banks and re-charging systems to maintain. About 5,000 BTUs are required on the average boat for minimal A/C cooling. The average small DC refrigerator to cool a small ice box consumes about six amps per hour at 12.6 volts to gain 350 BTUs—by deduction, a 12-volt A/C unit would use nearly 100 amps at 12.6 volts to cool an average-sized sailboat. Perhaps if the ballast was all in batteries, this might be feasible. Otherwise, installing a generator and operating the air conditioner off 115 VAC makes more sense.