Range discrepancy in my Model S 100D

[Schreib]

Hi folks,

I have a Tesla Model S 100D 2017 with about 11,000 miles on it. I bought it as a demo/loaner car about 5 months ago, when it had 8300 miles.

The range reported by the battery meter seems somewhat... off. I ran a small experiment: I started Friday evening at 266 miles (charge limit 70%). For the following 24 hours, I drove 91 miles (as reported by "Miles since last charge") over somewhat hilly terrain, with light climate control settings.

Now, the charge meter is at 157 miles. That means 266 - (157 + 91) = 18 miles got "lost" somewhere. But the strange thing is, the Wh/miles for this trip is only 316 Wh/mile.

Extrapolating, this would suggest the battery capacity is 316 * 91 * 335 / (91 + 18) = 88.4 kWh. That seems way less than the advertised 100 kWh, even adding in the various buffers, no?

Where did the 18 miles go? Is it
A) The battery capacity is actually this bad, or
B) The Wh/miles does not take into consideration 24h vampire drain + climate control use (18 miles lost to either still seems way high though)

Thanks for any guidance!

 

[DCGOO]

The answer is B.

 

[SubSolar]

I've had an S and now an X and I never get close to the range indicated. I get somewhere between 75 to 85%. Never had a speeding ticket in my life, drive 70 to 75 mph always on the freeway. You'd need to drive with no hills, 60-65 mph, no AC, perfect weather, to get what it states I think.

 

[DCGOO]

TBH, the number displayed in the IC was never intended to be an accurate indicator of real range. The "gauge" just shows how full the "tank" is. For estimated range, use the range shown in the Energy Graph. It is reasonably accurate, because it takes into account the last 5, 15 or 30 miles (your choice) of actual driving and real energy consumption.

I would recommend setting the car to display % battery, 0 to 100. Much easier to understand and follow, IMO.

 

[Schreib]

Thanks everyone for your really helpful replies. DCGOO, I'm glad to learn that it's actually B. Are you sure that climate control and other things (like charging the 12V battery) are not included in the car's Wh/mile report?

I learned that, actually, only 94 kWh of the battery's capacity is usable, so I redid my math.

According to the battery status meter, I spent (266 - 157) / 335 = 32.5% of the battery's usable energy. That's 94 * 0.325 = 30.6 kWh. If we multiply the trip report's miles and Wh/mile together, we get 91 * 316 = 28.8 kWh. That means that "only" 1.8 kWh were lost to vampy drains and climate and misc things, and possibly degradation. That seems much more reasonable. So actually, I was wrong in feeling that things were unreasonable.

The spanner in the works is twofold: I assumed that the 335 miles figure is based on ~300 Wh/mile. It's not. It's more like 280 Wh/mile. And then I thought the battery was bigger than it was.

My conclusion is that you'll only get the advertised 335 miles if you drive at ~280 Wh/mile, with possibly climate control disabled.

 

[DCGOO]

Thanks everyone for your really helpful replies. DCGOO, I'm glad to learn that it's actually B. Are you sure that climate control and other things (like charging the 12V battery) are not included in the car's Wh/mile report?

It is included only during the time the car is on you are driving. Energy consumed while the car is off, is not counted. That can include climate, battery heating/cooling, 12v etc.

 

[ek993]

As others have mentioned, switch to battery % versus miles which are totally meaningless. Took me a few weeks to adjust after years of driving ICE cars.

 

[Uncle Paul]

My favorite way to gauge range is when using Navigation.
At the bottom of the directions it will show how much battery you should have on arrival.
Depending on how you drive that calculated reserve will go up or down, depending on how you are driving.
It may start at 20%, but then go up to 22 or 25% if you are driving efficiently.
Sometimes it will indicate that you will need to slow down if you are going to arrive with your preset buffer.

Seems to be pretty accurate. If it looks like I am going have less buffer that I want, I have the choice of driving more efficiently, or making do with a lesser buffer.

It also makes a handy calculation of how much % you will have if you want to return to your original destination. Sometimes it will show a negative %, and that lets you know that you will need to recharge somewhere to get back home.

With all this information, I rarely have range anxiety. Pretty easy how to figure out the best charging strategy on longer trips.

 

[DCGOO]

Thanks everyone for your really helpful replies. DCGOO, I'm glad to learn that it's actually B. Are you sure that climate control and other things (like charging the 12V battery) are not included in the car's Wh/mile report?

I learned that, actually, only 94 kWh of the battery's capacity is usable, so I redid my math.

According to the battery status meter, I spent (266 - 157) / 335 = 32.5% of the battery's usable energy. That's 94 * 0.325 = 30.6 kWh. If we multiply the trip report's miles and Wh/mile together, we get 91 * 316 = 28.8 kWh. That means that "only" 1.8 kWh were lost to vampy drains and climate and misc things, and possibly degradation. That seems much more reasonable. So actually, I was wrong in feeling that things were unreasonable.

The spanner in the works is twofold: I assumed that the 335 miles figure is based on ~300 Wh/mile. It's not. It's more like 280 Wh/mile. And then I thought the battery was bigger than it was.

My conclusion is that you'll only get the advertised 335 miles if you drive at ~280 Wh/mile, with possibly climate control disabled.

The advertised range is only 295, not 335. So you might want to run the numbers again.