You may have missed the part about the last step hill climb. I thought it did quite well making it about a mile up on that climb, near the end of its available power. Without the hill climb I figured that I would have made it about 30 miles instead of 26.
On the ride from Furnace Creek to Bad Water I held a steady 35mph. The road constantly rises and falls consisting of long but shallow climbs and drops. Each one of about 1 to 2 miles long or so. As soon as I turned onto the steep climb of Artist Drive I lowered my speed to 20mph and held it steady at that. I got very close to the top of the climb when it quit. Had I gone over the top I would have made it another two or three miles, taking advantage of the downhill.
I probably cost myself the top because as I rode past the other riders, who were parked by the road and cheering me on, I went full throttle there, accelerating up the hill past them, just to show it was me holding 20mph and not a power limitation of the DS. I knew, of course, when I did that, it would blow a lot of available distance.
The last mile climb is steep enough that when the motor cut off, the DS started to roll backward and I had to grab the brake before I lost it.
All in all it exceeded my expectations, considering the nature of that ride. If the DS had a freewheel, like a bicycle, I could have taken better advantage of the downhills. The rolling drag of spinning the motor takes a lot of energy out of the bike. A free rolling system would add available distance to stop and go city or up and down country riding.
I'll be taking it to my desert cabin tomorrow (Anza-Borrego), for a week, and start doing longer dirt rides than I've done on the bike since I got it. They will be "jeep" trails with a lot of sandy areas. It is going to be interesting to see how much distance I get on that type of riding.