Charge Stats in Tesla App May Be Understating Gas Savings

[Let's Drive]

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.

Yeah, it says the equivalent is 28mpg for the Model 3. Considering my M3P competes with other performance cars, and those are around 16-18mpg (and require premium), the savings is absolutely understated.

 

[mwhitelaw1]

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.

How do u enter the gas price manually on the app?

 

[mwhitelaw1]

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.

How do u enter gas prices manually on the Tesla app?

 

[Big Earl]

How do u enter gas prices manually on the Tesla app?

You can’t. It uses the average gas price of the home location you have set in your Tesla account. The only thing you can change are the electricity prices for home and other. Supercharger prices are based on your actual usage.

 

[travasky]

This site also has a calculator you can use that has a lot more flexibility in how you do your calculations. You can set your electricity rate and the MPG of your gas vehicle you want to compare it to.

Electric Vehicle Savings Calculator | ChargEVC

 

[mstatkus]

I did a rainy day project with some open APIs I could find to pull in data. EnergyCalc.
Did it mainly for a few people that had spreadsheet phobias . Unfortunately the most current power rates I could find were from 2012 ( but you can manually tweak if you know that info). So many friends didn't even know what most of the acronyms meant so I tried to back it up with help.

 

[travasky]

I did a rainy day project with some open APIs I could find to pull in data. EnergyCalc.
Did it mainly for a few people that had spreadsheet phobias . Unfortunately the most current power rates I could find were from 2012 ( but you can manually tweak if you know that info). So many friends didn't even know what most of the acronyms meant so I tried to back it up with help.

That site is awesome! Nice work.

 

[SlimJim]

Mine is overestimated by about $40.
This is probably because i sit in the car for 1 hour each day during my lunch and it consumes power.

 

[Jejunjm]

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

Cool! What's the efficiency ac-dc that you get. Mobile charger is 30 amp?

 

[mstatkus]

Mine is overestimated by about $40.
This is probably because i sit in the car for 1 hour each day during my lunch and it consumes power.

I thought about adding some cold/hot multipliers or added weight, but it would be ballpark 10-15% up to 50% towing and that average watt hour. I sit in the car for as much as a hour while my wife is at an appointment and run stuff and TezLab always shows my efficiency drop to 64% vs my normal 85-90%. Knowing climate by zip code may help estimate over the advertised watt-hour or kilowatt-hour.
Heat pump vs resistive heating also makes it tough to guesstimate.

 

[JimShaw]

I went 100%+ solar about 12 years ago. I purchased a M3 SR in 2019. My electrical bill comes do once a year period. That's when either the electric company pays me or I pay them. The first full year of the Tesla charging along with my home, I ended up paying $85. ??

This year I sold the SR and purchased an 2022 M3P. This will make the bill at the end of the period a little higher but no worth thinking about

Nothing finer than a 100% solar home and a Tesla

Life's good

 

[travasky]

I went 100%+ solar about 12 years ago. I purchased a M3 SR in 2019. My electrical bill comes do once a year period. That's when either the electric company pays me or I pay them. The first full year of the Tesla charging along with my home, I ended up paying $85. ??

This year I sold the SR and purchased an 2022 M3P. This will make the bill at the end of the period a little higher but no worth thinking about

Nothing finer than a 100% solar home and a Tesla

Life's good

What are you using for the whole house battery?

 

[JimShaw]

What are you using for the whole house battery?

I do not have a battery. It all goes to Edison who pays me if the solar produces more energy than I used for the year

 

[Tom76]

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:
View attachment 779230

Charge stats as of today:
View attachment 779226

Gas in NY now averages 4.13 per gallon. Yet in the charges stats it shows NY gas average as 5.55. Who inputs this info and how can I change to reflect the proper average?

 

[mstatkus]

Gas in NY now averages 4.13 per gallon. Yet in the charges stats it shows NY gas average as 5.55. Who inputs this info and how can I change to reflect the proper average?

Only thing I’m aware of with any state wide accuracy is AAA Gas Prices and it can get down to a county level. But most high level apps will most likely work with a average price at a higher level.
I had similar issues just finding actual power rates. Most the data was a decade old. So its ballpark but requires some to look at their bill or find out if the power company was renamed since.

 

[ope_sorry]

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

Since my car is less than a year old, I was able to use the "Year" function to get my total kwh and my odometer reading to get total miles. This sent me down a bit a rabbit hole but for someone like me in cold climate the gas savings are WAY overstated. It must assume I use all my kwhs efficiently when many times my car uses as much energy keeping my battery warm in the parking lot as it does propelling me on my 12 mile commute.

Basically I used miles driven as my starting point to back calculate estimated gas costs. Compared to the Tesla method, I get way less savings (but still in the green). I should note I live in one the coldest areas in the lower 48 so I am not an average case, but this does highlight that Tesla must be using some conversion factor from kwh to gallons of gas. My gas vehicle does not consume gas while sitting in a cold parking lot and that factor effects the numbers greatly.

Here is my math: