Well its starting to get cold in New Jersey so I turned on the heater in the MINI E. While driving with the Air conditioner on in the summer, barely used any electricity, I was shocked by just how much the batteries dropped when I turned on the heater. I've only run the heater for a couple days now, but the numbers are not looking good. During the summer a drive to work and back with no side trips and all on back roads a drive of 33.5 miles used 27% of the charge, but with the heater at half way and the fan on just slightly the same trip used 37% of the charge. Total range estimates are not that precise when based on these short trips, but my range has dropped from about 110 miles a charge to about 80, and this is on back roads never going faster then 45 mph. What will happen when I'm using the heater at max and driving on the highway? I'm worried about some of my longer trips, like to my fiancee's home, which is a 77 mile trip on mixed roads that uses 82% of my charge, I only have 18% to spare for heat on that trip. I'm also wondering whats the optimum temperature for the batteries, during the summer MINI recommended you use the AC to keep the batteries cool, which actually improved range, but with the heater drawing so much power I doubt it will be improving range unless its below freezing, I may be driving with my gloves on this winter.
Its still too early to say how significant heater usage is going to be, I'm going to need to collect more data ie drive with the heat at different levels. Got about 6 months to test the heater coming up.