Question: Does enabling NAV reduce your EV range? Background: I hadn't plugged in my NAV SD Card, because I didn't want NAV. Unfortunately the dealer only had models on the lot with NAV. I was thinking of selling the SD Card to try to recoup some of the cost of the NAV, but I checked ebay and found that the SD card is a mere fraction of the cost. Presumably the GPS and other(?) systems embedded in the vehicle are the bulk of the expense. I've been driving for a week or so without the SD card plugged in, the same commute over and over. The other day I plugged in the NAV's SD card and I get the impression the number of miles listed as remaining in EV mode has been subtly affected. Surely enabling the NAV has a drain on batteries. The touch screen is constantly showing the current street name on screen whether I've got a destination enabled or not. Those calculations/lookups are free. Does anyone have any data on NAV? Should I just leave the SD Card unplugged if I want to optimize my EV Range? My iPhone's Waze app has considerably better traffic and incident information and presumably better routing too - and I can charge that one at work for free. ;) Thanks, Joseph Elwell.