Of course this is using the "I70 test Cycle", so may only apply in Colorado. Remember, YMMV (Your milage may vary), and with a Volt in the mountains, it may vary a lot!.
Returning from our weekend trip, I set a new personal best: 75miles on a single charge. There was no midday recharging, no mountain mode games and no hyper-milage tricks or slow-poking it. Most of the 75 miles was highway speeds including occasionally passing other cars/trucks. That's part of what I love about the Volt.. I can drive normally and still get outstanding performance. (Well driving the speed limit may not always be normal for me, My last car would often drive above the limit, if it was able. The Volt's digital cruise control lets me keep to it :-)
The trip started at Keystone CO, with 48m estimated range and at about 9000' elevation. We climbed up the Loveland pass to 11,990 ft. Our speed was mostly 45 until we passed A-Basin (5miles), when it gets twisty and we slowed to 35 and dropped to 25 for 2-3 really sharp hairpins). We reached the summit after about 9miles travel with 10m/2bars showing. The uphill climb really eats the juice, 75% charge used in just 9 miles.
We stopped for pics at the top. And yes that is snow in the upper left of the Pic. The temp was 65, but when the Colorado snows get really deep from the Spring storms, drifts can last a long time.
Next came the fun part, down the twisty road on the other side. Using cruise control set at 35, I enjoyed how the Volt limited its own speed producing lots of regen with out a lot of mental/foot games. My wife was pulling out the manual to see if this was allowed behavior, using cruise-control rather than breaks for the whole down hill. After 6 miles of down hill the Volt was showing 17m/4bars when we joined in to I70 (15miles traveled). I put it in cruise control to limit myself to the legal speed and just drove with traffic. The Volt was showing 30m/5bars when we hit Georgetown (27miles traveled). When we reached c470 after 65miles traveled it was still showing 13miles, 3 bars. There were a few bunching with slow downs at Georgetown and idaho springs, where trucks can only do 45mph, but we covered 65 miles in 70min from when we started, including the stop at Loveland for pics, so our average mph was pretty close to the legal limit of 65. We took an hour hike and lunch break at the Dino-lots where 70/c470 meet. When we continued the trip, the Volt showed 15m/3 bars (sitting made it higher??). Then traveled on C470 at 65mph for about 7 miles, exited onto Santa Fe Drive and the last 3-4 miles were at 50mph. Snapped a picture before when we got off the highway (71.4miles) then and wanted my wife to a perfect shot with max range and no gas, but the countdown on miles at the end was very very fast. We went from 1 mile down to 0miles and switched into CS in a few hundred yards. My wife missed the ideal shot waiting for the camera to initialize. We were flowing with traffic I was not going to pull over just for the shot. (My wife already thinks Im a bit crazy about this Volt :-) The remaining 33 miles were on CS mode. For those that care, tires were at 38 when we started (40 after they got hot), lights on, radio on, just fans until we got back on C470 after our break, when we switched to eco @74 as it was 88 outside. Passengers + luggage were about 400lb.
Overall for the weekend we did 303.2 miles and only burned 3.90 gallons of gas, averaging 77.45mpg in mountain travel while traveling in style, at normal highway speeds and even using A/C. Overall we did 175 CD miles and 127CS miles. CS mode milage was much lower going up, where we used the real mountain mode to keep 65+ mph uphill. Overall CS was 32, as the volt had to work for the uphill sections at both ends of the trip. I charged before we left and twice at the condo so the average CD miles per charge, over the three charges, was 58 miles per charge. (Individual EV legs were 55.6, 45.2 and 75.)
Of course this personal best is inflated by the downhill nature of the trip return, but it is still well above my prior personal best of 53 before the trip. (My wife and I did a mixed driver 55.6 CD mode on the way up for the weekend. I'm not as patient or talented a hyper-miler as honoreitiscom who has done 72+ on flatlands http://gm-volt.com/forum/showthread....-on-One-Charge. But I figure one should make good use of one's environment and so I did -- I figure it is only cheating if its not natural. With some effort (e.g. not driving at highway speeds), I know I could do better. Might be interesting to see if I could do 100miles with hyper-milage tricks, but as I said I'm not that patient. Maybe next time I'll get luck and there will be traffic jam on I70, then I'll be forced to go slow without doing anything special.
Raw Screen Photos: at http://innovation.uccs.edu/~tboult/t...-71p4miles.jpg and http://innovation.uccs.edu/~tboult/tmp/Volt-75miles.jpg.
Another photo from the top: http://innovation.uccs.edu/~tboult/t...untainview.jpg
Route Data http://maps.google.com/maps?saddr=ke...1,2,3&t=h&z=10