I have a new theory on this subject. As of Sunday, I was getting 220/219 for a 90% charge. On Monday, boom, 213. I thought "meh, one time thing." On Tuesday, same... 213. I had only seen 213 after a "90% charge" once before. It was sometime last week, maybe Thursday. We had barely driven the car the previous day. Then we had it plugged in at about 213, and in the morning, even though it was set to 90%, which had been 220, it was still at 213. So I thought "either the car thought 'well, close enough, why bother charging?', or the minimal time it took to charge had meant vampire loss had kicked in and brought it right back down". I had seen similar "Since I'm pretty much at that charge state already, I don't feel I need to charge" behavior from the car in the past, so it didn't surprise me to see something similar again.
now, after I've seen it randomly drop off those 6 miles overnight, I'm thinking that when we plug it in and it doesn't have much to charge, it starts to learn that as the "new 90% (or whatever % you charge to)". This would affect people who barely drive their cars more than it would those who drive more.
or maybe, but less likely, when you hop in and vampire drain has been reducing it since it stopped charging, it is learning that as the new "set percentage".
While I highly doubt what we are seeing as degradation (which is why I'm not worried in the long run), especially as some of the heaviest drivers are seeing the least "loss", this is a serious issue that tesla does need to address. Since I am not going to take the chance and drive it below zero, even if the car is just miscalculating the amount of energy it had, this turns into real loss of range (even if it isn't real loss of battery capacity). Losing 30 miles of range is over a 10% loss. That isn't minimal. I can justify that most drives it's fine and it really is similar to other factors (like wind), but at some point this needs to be addressed and fixed. I'm not as stressed about it as it probably isn't actual battery degradation, but it does require acknowledgement and addressing from Tesla.
a month ago, I was getting home from my daily commute with 25-30 miles of range to spare. Now I get home with 16-19. Soon it will be 0. While I could slow down below the speed of traffic to help alleviate the getting home with 0 range initially, that shouldn't be necessary if it wasn't necessary when I started doing this commute.
