I'll attempt to explain this again. It is covered in the various threads referenced above as well. The key here is to use your
consumption constants for the vehicle.
It actually sounds like you are doing quite well given it has been nearly three weeks since you charged. Everything seems normal. Thanks for providing all the necessary information to fully explain your situation (that is relatively rare around here).
Here are the constants:
List of current constants, and the position of the solid line on the Energy Consumption graph:
AWD: 250Wh/rmi solid line, 245Wh/rmi charge, 230Wh/rmi discharge
LR RWD: ~239Wh/rmi solid line (?), 234Wh/rmi charge, 223Wh/rmi discharge
LEMR: 242Wh/rmi solid line, 237Wh/rmi charge, 226Wh/rmi discharge
SR+/SR: 224Wh/rmi solid line, 219Wh/rmi charge, 209Wh/rmi discharge
Notes:
- "rmi" is the unit of "rated miles." It is not to be confused with miles, which has totally different units (distance, of course).
- These constants do not change, even if your battery "degrades" or loses capacity, or even if the BMS estimation is a little off. They can only be changed by Tesla during a significant software update which actually implements an efficiency improvement (this is very rare). The only time they may not work is if the BMS is extremely broken (I have never seen that).
. October first I did a 90% charge which showed 200 mile range.
Great, sounds like you have your full rated range and a healthy battery . This means your
available discharge energy (what you have available to use on the trip meter, in one continuous drive, before displaying zero rated miles on the battery gauge) at 90% is:
200rmi * 209Wh/rmi = 41.8kWh. At 100%, you would have 220rmi*209Wh/mi = 46.0kWh available.
In the past 20 days I have driven 119 around town conservative miles which are reflected in my 170 watts/mile usage since last charge.
You are a very chill driver, very efficient. So you used 119 mi * 170 Wh/mi = 20.23kWh. Remember that the "since last charge" shows none of your energy usage while in park.
My battery icon currently shows 54 miles range remaining versus (200 minus 119) = 81.
This means you have 54rmi * 209Wh/rmi = 11.3kWh remaining before getting to zero rated miles.
You can't subtract 119 miles from 200
rated miles, because these quantities
do not have the same units (that is how you know that calculation is wrong).
My energy screen past 30 mile average watts/mile is 162 with projected remaining range of 73. I am having a hard time reconciling these numbers.
This calculation uses the "charging" constant of 219Wh/rmi, for some reason (no, it doesn't make a lot of sense, but it is what it is):
54rmi * 219Wh/rmi / (162Wh/mi) = 73 miles (exactly what you see)
200 mile range and over 20 days have driven 119 miles using 170 watts/mile or 20.23 kw.
Correct.
If my 50 kw battery is software 10% software limited to 45 kw, I should currently have about 24 kw remaining which, at 170 watts/mile historical use, equates to 141 miles of range.
As described above, you originally started with 41.8kWh available (90% of your full capacity).
You've used 20.23kWh while driving. You now have 11.3kWh remaining. So your uncounted loss is:
41.8kWh - 20.2kWh - 11.3 kWh = 10.3kWh.
Over 19 days, this equates to:
10.3kWh / 19 days / 209Wh/rmi =
2.6 rated miles / day loss (this is actually pretty good compared to most people. You might be able to get it to one rated mile per day but you'll need to disable even more features.)
Or, 10.3kWh/ 19 days / 46kWh =
1.2% / day (close to Tesla's 1% per day number).
If I were using anywhere near the 250 +/- watt/mile used to project range I could understand my numbers and charge if off to vampire loss, but using 170 watts/mile it just does not make sense to me.
The units are watt-hours per mile (energy per mile, which has units of force, FWIW).
250 Wh/mi is not a correct number for your car. It is not correct for any Model 3 in fact. Again, with the SR, you need to get 209Wh/mi to get the rated range (one rated mile used per mile driven). You can verify this yourself - on a long continuous drive, note the rated miles used, and the kWh used (Wh/mi * distance traveled, for accuracy). kWh used / rated miles used will equal 209 Wh/rmi (there are certain special cases - due to temperature & regen - where this won't be true, but most of the time it is true). 209Wh/rmi is definitely the constant.
If you had started with a full battery at 100%, and you did 170Wh/mi, your true range would be:
220 rmi * 209Wh/rmi / (170Wh/mi) = 270.5 miles. But you would have to do this as one continuous drive, to achieve that.
Regarding charging constant: You can see this during a charging event
if you don't unplug the cable. You can switch between energy & distance display, then bring up the charging display and read off the miles added, and the kWh added, when the charging is complete. You would need to add a lot of miles for accuracy (like, your upcoming charge would be a good time to do it).
You'll find the kWh to rated miles added ratio is 219Wh/rmi (to within the limits of rounding error).
Hope this all makes sense. Congratulations on your excellent driving efficiency. I am so envious. When I drive like a grandma I get 260Wh/mi, and that is on surface streets. It sounds like you have done minimal/no freeway driving - you should expect much higher consumption at freeway speeds.
It's cool how a full one third of your energy use went to vampire drain! That is impressive; really saving the planet with that standby drain. This is why I no longer worry much about my efficiency - it's use it or lose it!