Japan-based camper specialist ROCKY2 in Yokohama has begun selling an original 12V roof air conditioner that runs from a auxiliary battery with the engine off. The cooling-only model costs 480,000 yen, and the heating/cooling version costs 630,000 yen (tax excluded, basic installation included). The indoor unit protrudes about 15 mm; listed fitments include Delica D:5, Stepwagon and Freed. In a test on a Delica D:5 with a 200Ah lithium-ion auxiliary battery at 25 °C, with the engine off and no external power, the unit ran for about 16 hours 30 minutes.
