Humm, I rarely use AC and my battery is usually at least 3/4 full. Normally it only gets down 2-3 bars unless I'm going up a really steep hill. On regular highway driving it usually stays fully charged or maybe 1 bar down. I drive it very gently, usually hovering around 60MPH on the interstate. If I can find a semi to draft behind then I become an unwanted bumber sticker for that truck. What's your average MPG for your HCH?