I know you don't get the full battery capacity for driving, some is kept for emergency reserve and some just not to run the batteries flat, which would damage them. I also know that Tesla apparent does not want to disclose what the usable Kwh for driving is, for our cars (if I'm wrong, please correct me). So on a new car, I used the battery percent meter, did a long trip, caculated percent loss and how many Kwh were used for that trip in the trip meter. You then extrapolate to 100% use, and get an approximate Kwh usable for driving if things work well. But in my car I'm only getting 75-76Kwh, which is way short of 90Kwh and unofficial numbers of 82Kwh usable for driving, that I heard. I did my tests without stopping the car during the drive and with the battery charging and warm just before I left. I did the test twice 2 days apart, uphill from Manteca supercharger to Kirkwood, CA, and downhill from Kirkwood back to cupertino, CA Temperatures were not warm, but above freezing. First leg: Manteca supercharger to kirkwood was 85% to 15%, i.e. 70% used: 53Kwh on trip meter. If 70% is 53Kwh, 100% is 75.7Kwh Second leg: Kirkwood to home was 80% to 20%, 60% use showed 44.4Kwh on trip meter That means 100% is 74Kwh 187 miles, 3h26, very good consumption of 238Wh/mi due to the big downhill. Any idea why I'm getting so much less than the rated battery capacity? Did others do similar tests and get unofficial numbers of Kwh usable for driving on their car? Thanks.