During a family trip from McAllen to Denver, I charged my Model Y LR at Junction on I-10 (Cooper’s BBQ is to die for!), then went north to Sweetwater for the next charge. The route is all state and county roads. My nav did two things: the estimated state of charge at the destination fluctuated wildly. It also kept recalculating the route. I am used to the estimated SC fluctuating a bit, but this was nuts – 40% one minute and 5% a minute later. The temperature was also very high – it was 110 in Sweetwater. I wondered if the high temps were messing with the battery in some way, but from Sweetwater to Lubbock, everything was normal.

On the way back, I charged up in Sweetwater and noticed that despite putting more juice in the battery, the estimated SOC upon arrival in Junction stuck at 5%. I knew I had more than enough juice to make the distance. Once again, the nav went cuckoo during the drive. This time, my astute daughter noticed that the recalculations were happening when there was no cell service. Aha! This made sense.

The only fly in that assessment is that while charging in Sweetwater, we were right on I-20 – and I know I had T-Mobile service because I checked emails on my phone. (I have no idea what phone data service Tesla uses.)

Any ideas?