Charge Stats in Tesla App May Be Understating Gas Savings

[Jeremy3292]

As a fun little test I decided to see how accurate the "gas savings" was in the Tesla app. Per Tesla my equivalent gasoline cost is $253 however, I am calculating $315 in gas savings as of today. There are obviously a lot of variables that go into the calculation, so I broke it down below. In order to get to the Tesla gas equivalent amount, the avg price per gallon of gas would need to be around $3.29, which it was maybe 4 weeks ago. So who knows how often Tesla updates their reference gas prices, the app simply says "The current calculation is based on gas prices in South Carolina." I am also not certain I drove 2,159 miles in the past 31 days, even with a 60 mile roundtrip commute M-F. I am not how Tesla would get from kWh charged to miles driven other than how I outlined the math below. Feel free to provide your thoughts and feedback.

Avg price of regular gas in SC as of today: $4.08 Click Here for Source
MPG used per Tesla: 28 mpg Click Here for Source

My math:

Charge stats as of today:

 

[Young Phenom]

Have you set the price / rate for the "other" ?

It's only showing a $1 charge cost

You can also enter the average gas cost as well manually.

 

[Jeremy3292]

Have you set the price / rate for the "other" ?

It's only showing a $1 charge cost

You can also enter the average gas cost as well manually.

I have free supercharging and I exclusively charge at work, which is also free, so my rate is set to $0 at "other". I only charge at home if needed.

But I am more looking at the "gasoline equivalent" than the "gas savings" numbers. I haven't seen where you can change the gas cost manually.

 

[MaskedRacerX]

They should, 1) display the gas price being used and 2) allow for a price override (not unlike how the electricity cost operates in the app)

You can also enter the average gas cost as well manually.

Oh, no *sugar*, I didn't see that option the couple of times I've looked ... checking again

 

[terranx]

You can also enter the average gas cost as well manually.

Wait, where? I don't see that option.

 

[mcstravis]

Gas saving are even better in Canada where the average price is now equivalent to over $7 / Gal

 

[MaskedRacerX]

Wait, where? I don't see that option.

Yeah, I feel like this is applicable here ...

But seriously, I don't think it is, maybe they're confusing the Tesla app with something else, like Tessie has the same sort of analytics, and you can actually enter the gas price manually.

 

[Iain]

I wish I could change the mpg it uses. It's something like 30 mpg and my last truck got 14 mpg so my savings are far more than what it shows.

 

[Big Earl]

Miles driven cannot be calculated by taking kWh / Wh/mile because the Wh/mile calculation does not factor in energy usage when the car is in park (sentry mode, remote climate control, cabin overheat protection, battery thermal management, and any usage while you’re in the car but not in gear). Your actual miles driven will be lower than the 2,159 you calculated using this flawed methodology.

 

[Jeremy3292]

Miles driven cannot be calculated by taking kWh / Wh/mile because the Wh/mile calculation does not factor in energy usage when the car is in park (sentry mode, remote climate control, any usage while you’re in the car but not in gear). Your actual miles driven will be lower than the 2,159 you calculated using this flawed methodology.

Any thoughts on how to get from kWh charged to miles driven then?

 

[Big Earl]

Any thoughts on how to get from kWh charged to miles driven then?

There is no definitive, accurate way to do it based on the available information. You can estimate it, but it will vary significantly based on habits, routine, weather/season and vehicle model. Best I can recommend is to track your actual mileage over a period of time and compare it to energy used and displayed Wh/mi.

 

[Young Phenom]

Yeah I totally got the gas setting wrong. I was confusing it with being able to set the kw at home and other.

The gas uses the average gasoline price in your area for a comparable vehicle.

That leaves a lot to be desired.

 

[terranx]

Anyone know what mpg it figures for a “comparable” vehicle?

 

[Jeremy3292]

Anyone know what mpg it figures for a “comparable” vehicle?

28 mpg for M3. See link in first post

 

[terranx]

28 mpg for M3. See link in first post

Cool. My savings are considerably more then. I was averaging 18-19 mpg with premium fuel on my previous car (well I still have the car, but it’s no longer a daily driver). And realistically any other car I would have been willing to buy also wouldn’t have gotten 28 mpg

 

[MaskedRacerX]

Any thoughts on how to get from kWh charged to miles driven then?

I was looking at Tessie stats, it has distance, power used, and gas comparison (with manual $/g entry), so you can see a definite miles/kW, and from that do your own gas calc. It also exports to CSV which is pretty cool.

 

[rpiotro]

28 mpg for M3. See link in first post

Interesting. That was about what I was getting in my Q50 hybrid. So it works for me.

 

[Junk]

There is no definitive, accurate way to do it based on the available information. You can estimate it, but it will vary significantly based on habits, routine, weather/season and vehicle model. Best I can recommend is to track your actual mileage over a period of time and compare it to energy used and displayed Wh/mi.

 

[Junk]

Yes there is a way to get the REAL cost of what any EV costs. Buy a electric meter
and wire inline with your charger. It will show
you the KWHs used. That includes charging and any other losses. Take that and divide
by the miles driven. Then multiply by your
KWH rate. My Tesla Y cost me 4.5 cents
to drive at a KWH rate of .108

 

[Junk]

Yes there is a way to get the REAL cost of what any EV costs. Buy a electric meter
and wire inline with your charger. It will show
you the KWHs used. That includes charging and any other losses. Take that and divide
by the miles driven. Then multiply by your
KWH rate. My Tesla Y cost me 4.5 cents
to drive at a KWH rate of .108
View attachment 792006

That’s 4.5 cents per mile to drive.