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Suspicious range numbers

svoelpel

Member
Apr 6, 2013
40
31
North Carolina
I recently purchased a software limited M3 (220 mi range). October first I did a 90% charge which showed 200 mile range. 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. My battery icon currently shows 54 miles range remaining versus (200 minus 119) = 81. 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. I stared with 200 mile range and over 20 days have driven 119 miles using 170 watts/mile or 20.23 kw. 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. I have not had sentry mode or cabin overheat on at any time. 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. Appreciate any thoughts out there.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
10,839
12,568
Riverside Co. CA
The car will use 2-4 miles a day just "sitting there, doing nothing", so there is absolutely nothing wrong with your numbers / range.

If you want to read more about these cars and "range" just search this site for "my car is not getting rated range" and since there are at least 1 new post on this topic every 24 hours for the past 2 months at least, you will have plenty of reading material.
 

ewoodrick

Well-Known Member
Apr 13, 2018
5,285
4,270
Buford, GA
I recently purchased a software limited M3 (220 mi range). October first I did a 90% charge which showed 200 mile range. 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. My battery icon currently shows 54 miles range remaining versus (200 minus 119) = 81. 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. I stared with 200 mile range and over 20 days have driven 119 miles using 170 watts/mile or 20.23 kw. 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. I have not had sentry mode or cabin overheat on at any time. 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. Appreciate any thoughts out there.

After reading the first sentence, and getting too bored to read the remainder, your battery is okay. You car is okay.
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
10,889
13,633
San Diego
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! ;)
 
Last edited:

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
10,889
13,633
San Diego
You'll find the kWh to rated miles added ratio is 219Wh/rmi (to within the limits of rounding error).

Meant to mention this:

Note these kWh added during charging are DC Wh actually added to the battery. So they do not account for conversion losses and vehicle charging overhead.

Numbers from the AC mains (the numbers that really matter) will be 6% (for 11.5kW charging) to ~35% (for 1.44kW 120V 12A charging) higher than those “kWh added” on the charging screen indicate.

So, keep track of total rated miles added (not your lifetime efficiency) if you want to keep track of your energy costs, and scale appropriately for charging efficiency losses.
 

camalaio

Active Member
May 28, 2019
1,483
2,181
Vernon, BC, Canada
Some further notes adding on to @AlanSubie4Life 's excellent analysis.

First, truly extraordinary efficient driving. Well done.
I'm guessing you're doing extremely short in-town driving without using heat or AC, based on your efficiency. Note that a gas engine performs very poorly compared to EPA ratings in this case, as the engine barely gets warm (optimal efficiency) before you're done driving. Even if you lose quite a lot to standby, you would've also lost a lot in a gas vehicle due to engine warm-up inefficiencies. Adding to that, if they're infrequently driven (once every two weeks, say) you may have to go run the gas engine just to charge the 12V battery!

Of course, when you do need to use heat/AC more, your efficiency will get a bit worse. For now, absolutely nothing to worry about.
 

svoelpel

Member
Apr 6, 2013
40
31
North Carolina
The car will use 2-4 miles a day just "sitting there, doing nothing", so there is absolutely nothing wrong with your numbers / range.

If you want to read more about these cars and "range" just search this site for "my car is not getting rated range" and since there are at least 1 new post on this topic every 24 hours for the past 2 months at least, you will have plenty of reading material.
The car will use 2-4 miles a day just "sitting there, doing nothing", so there is absolutely nothing wrong with your numbers / range.

If you want to read more about these cars and "range" just search this site for "my car is not getting rated range" and since there are at least 1 new post on this topic every 24 hours for the past 2 months at least, you will have plenty of reading material.
The car will use 2-4 miles a day just "sitting there, doing nothing", so there is absolutely nothing wrong with your numbers / range.

If you want to read more about these cars and "range" just search this site for "my car is not getting rated range" and since there are at least 1 new post on this topic every 24 hours for the past 2 months at least, you will have plenty of reading material.
After reading the first sentence, and getting too bored to read the remainder, your battery is okay. You car is okay.
After reading the first sentence, and getting too bored to read the remainder, your battery is okay. You car is okay.
 

ewoodrick

Well-Known Member
Apr 13, 2018
5,285
4,270
Buford, GA
ewoodrick - If you were too bored to read the entire post it would also been a better use of your time not to post a sarcastic reply.
There was really no sarcasm there. Indeed, the first line matches the post of many other posts.

Instead of throwing all sorts of details in my reply, I thought that I'd keep it real simple.
 

derotam

Member
Oct 31, 2018
864
810
Oak Hill, VA
ewoodrick - If you were too bored to read the entire post it would also been a better use of your time not to post a sarcastic reply.

You searching the site and perusing the plethora of range related threads would have allowed us to better use our time too.

Edit: for the technical aspect of responding to your OP...your car is fine. :)
 
Last edited:

Phlier

Bluebird
Jun 12, 2019
1,944
3,443
Utah
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
We really need that information in a sticky post at the top of the "Battery and Charging" sub forum.
 

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