So try to follow along with this napkin math. I'm going to define some well known facts to start:
A. 90D pre-refresh nominal capacity 85.8kwh
B. 90D pre-refresh usable capacity 81.8kwh
C. 4kwh brick protection, cannot use (A minus B)
D. Watts per mile used to calculate EPA rated range for pre-refresh 90D, 290 watts per mile.
So I've been bringing up with support this issue of disappearing range at the low end of long trips. It was suggested that this was just the BMS recalculating based mainly on pack temperatures lowering, impedance rising, and general tomfoolery of mysterious algorithms. However, I am seeing, both while driving and after short stops of 10-20min, the battery level drop by 4-6% in the blink of an eye. I only notice it when the battery gets down to the teens. It had proven disastrous on two long trips so far. 4-6% literally could make or break getting to the next supercharger since 4-6% is about 13-16 miles of range.
Now here is the data from the BMS at 62k miles:
A. Nominal pack capacity 79.1kwh*
B. Usable pack capacity 75.1kwh*
C. Full rated range 272-273 miles
*These numbers drop understandably so by .8kwh when the pack is in the single digits.
To get 272 miles, you need to multiply 290 watts per mile EPA by the usable pack capacity, right? Wrong. The only way to get to that number is using nominal pack size, of which there are 4kwh you could never actually tap into. So while the car says I can do 273 miles on a charge IF I consumer 290 watts per mile (which I can do on lots of long trips I take), my actual ability to travel is much less. How much less? Well, exactly that missing 4-6% the car says I have then suddenly says I don't.
So to sum up, the car says I can go 273 miles. But if you do the math, I can only actually go 258 miles (at 290 watts per mile), and eventually the car realizes this, at the end, when I need it....
Fun fact, if the 75.1 number is to be believed, and it should be because it's from the BMS, then that's 10% battery degredation in 2yrs on a 90kwh pack.
A. 90D pre-refresh nominal capacity 85.8kwh
B. 90D pre-refresh usable capacity 81.8kwh
C. 4kwh brick protection, cannot use (A minus B)
D. Watts per mile used to calculate EPA rated range for pre-refresh 90D, 290 watts per mile.
So I've been bringing up with support this issue of disappearing range at the low end of long trips. It was suggested that this was just the BMS recalculating based mainly on pack temperatures lowering, impedance rising, and general tomfoolery of mysterious algorithms. However, I am seeing, both while driving and after short stops of 10-20min, the battery level drop by 4-6% in the blink of an eye. I only notice it when the battery gets down to the teens. It had proven disastrous on two long trips so far. 4-6% literally could make or break getting to the next supercharger since 4-6% is about 13-16 miles of range.
Now here is the data from the BMS at 62k miles:
A. Nominal pack capacity 79.1kwh*
B. Usable pack capacity 75.1kwh*
C. Full rated range 272-273 miles
*These numbers drop understandably so by .8kwh when the pack is in the single digits.
To get 272 miles, you need to multiply 290 watts per mile EPA by the usable pack capacity, right? Wrong. The only way to get to that number is using nominal pack size, of which there are 4kwh you could never actually tap into. So while the car says I can do 273 miles on a charge IF I consumer 290 watts per mile (which I can do on lots of long trips I take), my actual ability to travel is much less. How much less? Well, exactly that missing 4-6% the car says I have then suddenly says I don't.
So to sum up, the car says I can go 273 miles. But if you do the math, I can only actually go 258 miles (at 290 watts per mile), and eventually the car realizes this, at the end, when I need it....
Fun fact, if the 75.1 number is to be believed, and it should be because it's from the BMS, then that's 10% battery degredation in 2yrs on a 90kwh pack.