My car (2016 90D, Model S) has a slightly degraded battery (72-73 available kwh) and it still displays a 275 mile range when fully charged. My actual range, driving at 340 wh/mi, is about 200 to 220 miles. The cars display of range takes no account of battery degradation. This was a dealer demo car with 7,500 miles on it when purchased. I was fairly certain that my actual range was less than advertised from day one. Miles driven and remaining range did not correlate. Even after correcting for a slightly higher wh/mile. Also kwh used compared to percent of battery used repeatedly revealed a 72-73 kwh available battery capacity. But these were for a portion of battery use of around 50%, so they were suspect. I finally got a Tesla rep on the phone who instructed me to take 3 trips that brought the battery from 100% to around 10% and make note of range, wh/mile, and kwh used. Taking a trip which terminates at 10% SOC is a bit tricky to plan. But I did it. Once so far. I plotted this on a few spreadsheet graphs and found that the miles driven, energy used, and SOC display all correlated very well throughout the trip. It was all quite linear and well calibrated. This validated my earlier measurements of decreased battery capacity. And confirmed those measurements of battery capacity of 72-73 kwh rather than the expected 85 kwh of available energy. Now I need to find the time to repeat the test two more times and see what Tesla has to say. Is a 15% degraded battery worth complaining about?