I've been struggling with efficiency tactics. I can ace the "efficient driving" test, but so far, I'm failing the "efficient slowing down" test.
Over 8,000 miles since June, we're at 305 wh/mile in our P85, including a number of cold weather trips (and, yes, some heavy "happy foot" driving too). By driving efficiently on uphills and flats, I can usually do better than rated and get more range, but on the downhills, I can never match the energy graph. (For cold weather range preservation, the huge one is heating the car up before you unplug. On long distance trips, we see the superchargers as superheaters as well. Leave the plug with a warm, fully charged car and it will greatly help you preserve range and get you as close as possible to rated consumption.)
On the regen, here's what I've been doing (not that I'm sure this is right): My thought is that coasting (feathering the throttle so there is little to no charge or draw taking place), the car is most efficient. When regening electricity by slowing down, there are losses in that, so if you're going down a hill and heading back up it again, it seems like its better to let the car coast above the speed limit and carry through the trough with more velocity than regen down the hill at 55 mph.
I guess the real question for this is: am I losing more energy through aerodynamic losses attributed to higher downhill speed, or through system losses when regening to keep the speed lower?