Bobbo wrote:
A few years ago, we spent a week in Yellowstone in September, when temps got down to or below freezing at night. We have 2 group 27 batteries. We learned the first night that we couldn't keep the thermostat set at 69 degrees all night. The furnace's fan ran the battery down about halfway through the night.
When we started turning the thermostat down to 45 degrees at night, we could get 2, maybe 3 nights on a charge.
Check your batteries if that's the case, I routinely get 3 nights with the stat set to 65 on 2 group 27 batteries.