Comparing cost per mile using total energy from trip screen metrics vs wall charger metrics and compared with ICE

[honor_the_driv]

Your Tesla reported 16 kWh used while the Tesla wall reported 20.7 kWh added to come back to 80%. So, the efficiency of charging is 16/20.7 = 77%
To have an accurate report you should charge your Tesla to 100%, drive it then come back and charge to 100% back. Usually the difference between the 2 values is 18-20% for Tesla Model 3. For the Tesla Y it is indeed about 22%. It is believed that it happens because Tesla doesn't count the kWh while parked. Or it really has a shitty on-board charger.

So I just learned how to get the charging stats for a single day by long pressing on the chart in the Tesla app. Currently I have my charge schedule set to start at 11pm so the charging may have gone across days, which would mess up the results.

I'm going to change the charging schedule to start at 12:30am and then I'll redo the above analysis so I can also see the charging efficiency. and understand how much energy is used for purposes other than driving.

 

[honor_the_driv]

On a separate note that is only barely related, I remember that when I was researching the car prior to ordering I saw plenty of comments about how the estimated miles left the car reports tends to be overly optimistic by a wide margin. For that reason I usually show the batter percentage instead of the estimated miles remaining.

I few days ago I tried out showing the miles instead and compared the estimated from the beginning and end of the trip with the trip computer metrics. In every case the difference between initial and final estimate has matched the trip metrics or been off by just a mile.

Is the the experience of others?

A little context about my Tesla's recent driving conditions:

• Its fairly flat where I live, i.e. the only significant elevations changes are certain highway on/off ramps.
• We drive the car pretty gently, i.e. we don't accelerate hard and use the regenerative braking as much as possible.
• The weather for the last few days has been warn to kinda hot, but not scorching.

 

[voldar]

Is the the experience of others?

Yes, as long as the efficiency of the trip is about the same as the one used by Tesla to show the rated range.

 

[honor_the_driv]

Yes, as long as the efficiency of the trip is about the same as the one used by Tesla to show the rated range.

I imagine that Tesla does not publish that info though, right?

 

[jjrandorin]

On a separate note that is only barely related, I remember that when I was researching the car prior to ordering I saw plenty of comments about how the estimated miles left the car reports tends to be overly optimistic by a wide margin. For that reason I usually show the batter percentage instead of the estimated miles remaining.

I few days ago I tried out showing the miles instead and compared the estimated from the beginning and end of the trip with the trip computer metrics. In every case the difference between initial and final estimate has matched the trip metrics or been off by just a mile.

Is the the experience of others?

A little context about my Tesla's recent driving conditions:

• Its fairly flat where I live, i.e. the only significant elevations changes are certain highway on/off ramps.
• We drive the car pretty gently, i.e. we don't accelerate hard and use the regenerative braking as much as possible.
• The weather for the last few days has been warn to kinda hot, but not scorching.

The estimated trip miles when you go on a trip using the in car navigation is not what people are complaining about being "wildly optimistic". The complaint isnt "I use the navigation system, check the trip estimations in the navigation computer, and when I complete the trip, its waaay off".

The complaint is (basically, to summarize) "I drove 6 miles to the store, and 11 miles rolled off the battery indicator", or " I drove to my vacation house, which is 80 miles away from my house, and 119 miles rolled off the battery indicator.

People are not comparing the navigation estimate, but simply looking at the "miles" on the battery and expecting those to roll off at 1:1 equivalent, and they dont (unless you drive like epa tests). Thats not the same thing at all as using the in car navigation, going to the energy screen and looking at the trip estimation.

 

[honor_the_driv]

@jjrandorin yes I know. I was not referring to the estimations of the trip distance from the navigation. I was referring to the estimate of the miles left from the battery indicator. I even said that I usually show the battery percentage instead of the estimated miles remaining .

For example, when I started yesterday's morning commute the battery indicator spot on the left portion of the screen showed an estimated 223 miles. When I finished the morning commute the estimated miles was198 miles, a difference of 25 miles. The trip computer also showed 25 miles and that is consistent with Google Maps. In other words, for my driving behavior and driving conditions the estimated miles left on the battery indicator seems pretty accurate, at least for the 60%-80% SoC that I usually stay in for most days.

 

[voldar]

I imagine that Tesla does not publish that info though, right?

No, but it can be deducted. For example, my rated range is 333 miles. The battery of the MIC version is 78.8 kWh. This makes the efficiency that was used to give the rated range is : 78800/333 = 237 Wh/mi (4.22 mi/kWh or 147 Wh/km).
This means, if I want to get the rated range, my trip efficiency should be around 237 Wh/mi.

 

[honor_the_driv]

The battery of the MIC version is 78.8 kWh.

Does Tesla publish the battery capacities for its cars or is there a way for me to confirm that in the car's interface? When I got the car I looked and couldn't find it then. When I search online I tend to see 67.6–81 kWh. I have the Model Y [Standard Range] AWD so I'm pretty sure my car's battery is 67.6 kWh but it would be nice if there was an easy way to confirm this.

 

[msinfo]

No, but it can be deducted. For example, my rated range is 333 miles. The battery of the MIC version is 78.8 kWh. This makes the efficiency that was used to give the rated range is : 78800/333 = 237 Wh/mi (4.22 mi/kWh or 147 Wh/km).
This means, if I want to get the rated range, my trip efficiency should be around 237 Wh/mi.

I've got a q - newer Tesla LR/P battery is 82.1kWh with ~4.5% buffer at the top to cover initial battery degradation which brings available capacity to about ~79kWh. So, when Tesla says range of 333miles is this for 82.1kWh or 79kWh? If the former then above calc would be 82100/333=247Wh/mi.

 

[voldar]

I've got a q - newer Tesla LR/P battery is 82.1kWh with ~4.5% buffer at the top to cover initial battery degradation which brings available capacity to about ~79kWh. So, when Tesla says range of 333miles is this for 82.1kWh or 79kWh? If the former then above calc would be 82100/333=247Wh/mi.

I mentioned in my message : MIC = Made In China battery (by LG Chem). This battery has 78.8 kWh capacity. Canadians get the Tesla made in China, because Elon wanted to let the Americans to be able to use the 7500 $ Federal Tax credit. Which is totally understandable for me.
The battery used for the Tesla LR build in USA is indeed of higher capacity, but I can't tell you exactly if it has the one made by Philips (82.1 kWh) or not. And because Tesla shows the same rated range for both Tesla on its site, it's not making it easier. Plus the fact that Tesla decided to reduce the rated range starting 2023 LR without a reason given besides "to show more realistic range". I know though that Tesla was asked by EPA to reduce their rated range by an average of 3%. 358 miles (EPA 2022) - 3% = 347 miles. It looks like the range for the 2023 was reduced by 7.5% in the case of the Tesla Model 3 LR AWD. Why ? I have no idea. But it does seem more realistic based on my experience with EV.

 

[msinfo]

Thank you. I missed/did not know what MIC stands for.

MIC = Made In China battery (by LG Chem). This battery has 78.8 kWh capacity.

 

[honor_the_driv]

Does Tesla publish the battery capacities for its cars or is there a way for me to confirm that in the car's interface? When I got the car I looked and couldn't find it then. When I search online I tend to see 67.6–81 kWh. I have the Model Y [Standard Range] AWD so I'm pretty sure my car's battery is 67.6 kWh but it would be nice if there was an easy way to confirm this.

@voldar , do you know?

 

[voldar]

@voldar , do you know?

Sorry @honor_the_driv I don't know of a Tesla source stating the batteries' capacity.