Thanks jj. I’ve been a teeth gnasher since I’ve owned my 3, almost a year. 90% every day and 4 miles range loss sounds awesome. I drive no more than 30 miles a day and most days much less. I’ve been charging to 70 % and then to 90% for a while now. I’ve read that the BMS works best at 90%. Based on your experience I think I’ll just leave it at 90%. Let me know what you think of the attached battery report.
For what its worth, even the 4 miles I "lost" happened in some firmware update in the middle to end of October, when my car went from 279 at 90% to 274 at 90%, where it still is, right now today. I am not a battery expert nor an expert on charging constants (going to leave that to
@AlanSubie4Life or others). From my own experience, and reading here, I believe that the BMS system has a harder time figuring out energy left in the battery when charged below 90%.
I want to be clear that I am not saying that charging to 90% is somehow "better" for the battery than charging to 80%. Battery science tells us that a lower charge is slightly better for the battery, after all. "how much" better 80% is than 90% is debatable, and its my belief that 80% over 90% is going to be a small difference over the lifetime of the battery... the order of a few miles, because tesla does not let us charge to a full 100% of the battery even when you charge to "100%".
What I AM saying is, is that my experience has been that charging to 90% and charging every day has been very good in allowing the cars BMS to show my rated range number without much change. Its my position that people either need to charge to 90% and leave it there, and charge every day (and do so for at least a couple of weeks to allow the BMS to balance), OR charge to whatever lower number makes them happy and stop looking at the rated range number going down and worrying about it, because its less accurate when charge that way.
New owners come here, read all this stuff on the battery, and get either intimidated or get it in their heads they have to somehow "manage" their batteries with magic bullets and formulas. I am just as guilty of this in the past as new owners now, so this is not me just throwing shade, its acknowledging what people are doing. They then start making post after post after post saying basically the same thing, which is:
====================
"I drive my car 25/25/30 miles a day, and I am super concerned that my battery now shows 8-10 miles lower than it used to as max range! My car only has 2/5/7K miles on it, what gives!?!??! I charge my car to 78% all the time like people say I should, WTF is wrong with it?!?!?!?!?!??!"
====================
Even typing it out, it looks silly. I understand WHY people do this.. because they are terrified that this new car they bought, that fills up with electricity is already broken, when its not. Gas cars lose "range" over time and no one cares. Gas cars get less efficient over time and no one cares. The argument normally is " well there is a gas station on every corner so its different". My rebuttal to that is, with an EV your gas station should be at your residence, so total range does not really matter unless you are a traveling salesman or some other person who wants to drive the entire range the car can go every single day, which very few are trying to do.
The person who drives 30 miles a day round trip has absolutely zero to be worried about if the range shows 7 miles "less than it used to" because they dont even know if thats accurate, and are unlikely to drive that entire range at once unless on a trip, and when ON that trip, will be dealing with other variables that effect range, like weather, wind, battery heating, cabin heating, etc... so that rated range number means absolutely ZERO yet people "wail and gnash teeth" about it because they feel batteries are somehow unreliable or something.
@hcdavis3 this is not directed at you btw, I am just on my soapbox right now and typing so I am talking in generalities about the 100s of people who come and make the complaint I said above in the brackets.
Anyway, the TL ; DR version of this rant is, people need to either stop trying to baby the car and just plug it in, let it charge to 90% and leave it there, or, if they want to "manage" the battery, charge to whatever they want and completely ignore the rated range number because its meaningless anyway as a predictor of how far you can actually go.