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Lifetime Energy Consumption for my Model S in Boston Area after 4 years

David29

Supporting Member
Aug 1, 2015
2,237
1,877
DEDHAM, MA
Last week was the 4th anniversary of the activation of my home charging set-up at my condo, so I thought it would be interesting to see how much energy I had purchased from our local utility, Eversource. (I live in eastern Massachusetts.)

I charge the car (a 2015 70D) with a Tesla Wall Connector connected to a 240 Volts single-phase 50-amp circuit. The cable run from the meter to the Wall Connector is roughly 25 feet. I usually charge at 40 amps.

There is a separate service and electric meter for charging my car, so it is (almost) easy to see how much energy the car consumed. I say “almost” because there was a brief gap in my data for which I made an adjustment. Plus, I have a motion-activated security lamp on the same service. The lamp does not run for very long when it activates, so I decided to ignore the lamp’s energy use, as it would be very small compared to the car’s.

In those four years, the circuit consumed 17,827 kWh, while the car went 41,033 miles. So, based upon these raw numbers, we could say that the car charging (including charging losses plus precooling and preheating) consumed an average of 348.7 kWh/mile driven. That compares to the lifetime average consumption shown by the car in July 2019 as 326 Wh/mile. (I lost my historical data at that time because of a computer repair.)

Unfortunately, that is an incomplete picture, because it does not allow for charging elsewhere, such as use of Superchargers and destination chargers on trips. I do not have very good records of charging away from home. So, I made an estimate of the mileage driven away from home over those four years and decided to allow 1,000 miles per year as a rough but reasonable allowance. So that means the Eversource energy was used for about 37,033 miles. The average energy use then looks like 481 Wh/mile, a much higher figure, and a bit startling. I know that charging losses have been estimated at 10% or so, but this would be quite a bit higher.

Most likely, the largest source of extra consumption is preheating and precooling the car. I tend to use that function quite a lot, because my car is parked outside, winter and summer. The car does not consider the energy used for that in the displayed energy consumption, when the car is connected to shore power. Since the car's heater can operate at as much as 6 kW, prolonged use of preheating in winter can add considerably to total energy consumption. Air conditioning does not consume as much, but even that does add something to energy costs.

At my current average price per kWh of about 23 cents, that translates to approximately 11 cents per mile for energy. That is not much if any savings compared to my previous car, which was a Mercedes that got about 20-23 mpg on premium fuel. Which I why I tell people around here that they should not buy a Tesla, or any other EV, with the goal of saving on energy. (The exception might be if they happen to live in a town or city with a municipal electric department, which typically provides energy at a much lower cost.)

My numbers do contain some assumptions, the most important of which is my allowance of 1000 miles per year for travel charged elsewhere. That may be conservative, and I hope it is, but it is not too far off. In any case, it is worthwhile to realize that charging losses may add to the energy consumption reported by the car. And in my case, preheating and precooling probably contribute substantially to the actual total energy used and the cost of it.

One other point: The precooling and preheating would be a smaller factor in cost per mile if I drove more. But I am retired, so I do not commute. And of course, since mid-March we have been driving very little because of the Covid-19 shutdown.
 

mswlogo

Well-Known Member
Aug 27, 2018
6,068
4,696
MA, NH
Yeah, it’s surprising how many Tesla’s I see around eastern Mass.

We have Solar. If you amortize the cost of Solar it’s about $0.08 /kWh and it makes the numbers much more attractive.

I also never preheat or precool. Very inefficient use of power. I also highly recommend a garage so you don’t have to melt the ice and snow off and keeps the car warmer in winter and cooler in summer.
 

EdA

Model S P-2540
Mar 24, 2011
2,286
245
Cape Cod
Right, solar and a garage will certainly help. I pre-heat/pre-cool when I'm away from home on occasion.
 

DrDabbles

Active Member
Jul 28, 2017
1,092
1,311
NH, US
Very cool. Something to consider is that if you get a decent OBD scan tool, you can connect one of the Tesla scan tool apps to your car and see the car's reported lifetime consumption and charging values for DC charging versus AC charging.
 

Two Hounds

New Member
Jan 26, 2020
3
3
South Shore, Massachusetts
very cool data, thank you. I'm also in Eastern MA- a little SW of you- and took delivery in December. I was surprised at the amount of loss due to the cold weather but it's been much better since. I'm on the road and had been using the Hooksett and Mansfield Superchargers pretty regularly- at least 50% of the time, I'd guess. Since March I have been driving much less and charging almost exclusively at home, where I have 2 banks of solar panels and a garage

That's a long-winded way of saying I have no clue how much it's costing me to charge- but I love it anyway
 
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StanT

Member
Jan 23, 2020
148
185
Fishkill
Very cool data... As a person from the Northeast, I think in most cases up here (I'm about 2 hrs north of NYC) the electric is cheap but the delivery cost is HUGE- like many more times than the cost of the electric. So solar savings may not be huge by kw but it helps a lot because you don't have to pay for delivery charges even when you net meter.

That said, thank you David29- you've encouraged me to start pay attention to my overall usage so I can have some cool stats like you when my MY is a few years old.
 

jasinflorida

Member
Mar 15, 2020
5
2
Lake Worth, FL
Last week was the 4th anniversary of the activation of my home charging set-up at my condo, so I thought it would be interesting to see how much energy I had purchased from our local utility, Eversource. (I live in eastern Massachusetts.)

I charge the car (a 2015 70D) with a Tesla Wall Connector connected to a 240 Volts single-phase 50-amp circuit. The cable run from the meter to the Wall Connector is roughly 25 feet. I usually charge at 40 amps.

There is a separate service and electric meter for charging my car, so it is (almost) easy to see how much energy the car consumed. I say “almost” because there was a brief gap in my data for which I made an adjustment. Plus, I have a motion-activated security lamp on the same service. The lamp does not run for very long when it activates, so I decided to ignore the lamp’s energy use, as it would be very small compared to the car’s.

In those four years, the circuit consumed 17,827 kWh, while the car went 41,033 miles. So, based upon these raw numbers, we could say that the car charging (including charging losses plus precooling and preheating) consumed an average of 348.7 kWh/mile driven. That compares to the lifetime average consumption shown by the car in July 2019 as 326 Wh/mile. (I lost my historical data at that time because of a computer repair.)

Unfortunately, that is an incomplete picture, because it does not allow for charging elsewhere, such as use of Superchargers and destination chargers on trips. I do not have very good records of charging away from home. So, I made an estimate of the mileage driven away from home over those four years and decided to allow 1,000 miles per year as a rough but reasonable allowance. So that means the Eversource energy was used for about 37,033 miles. The average energy use then looks like 481 Wh/mile, a much higher figure, and a bit startling. I know that charging losses have been estimated at 10% or so, but this would be quite a bit higher.

Most likely, the largest source of extra consumption is preheating and precooling the car. I tend to use that function quite a lot, because my car is parked outside, winter and summer. The car does not consider the energy used for that in the displayed energy consumption, when the car is connected to shore power. Since the car's heater can operate at as much as 6 kW, prolonged use of preheating in winter can add considerably to total energy consumption. Air conditioning does not consume as much, but even that does add something to energy costs.

At my current average price per kWh of about 23 cents, that translates to approximately 11 cents per mile for energy. That is not much if any savings compared to my previous car, which was a Mercedes that got about 20-23 mpg on premium fuel. Which I why I tell people around here that they should not buy a Tesla, or any other EV, with the goal of saving on energy. (The exception might be if they happen to live in a town or city with a municipal electric department, which typically provides energy at a much lower cost.)

My numbers do contain some assumptions, the most important of which is my allowance of 1000 miles per year for travel charged elsewhere. That may be conservative, and I hope it is, but it is not too far off. In any case, it is worthwhile to realize that charging losses may add to the energy consumption reported by the car. And in my case, preheating and precooling probably contribute substantially to the actual total energy used and the cost of it.

One other point: The precooling and preheating would be a smaller factor in cost per mile if I drove more. But I am retired, so I do not commute. And of course, since mid-March we have been driving very little because of the Covid-19 shutdown.

Fortunately I live in South Florida where the cost per kWh is only 12.9 cents. That make my 2020 Tesla Model S a bargain when it comes to comparing it with an ICE vehicle.
 

Gray468

Member
Jan 7, 2019
105
115
Santa Barbara
My lifetime average for my 2017 S is 247wh/mi.....

My fuel costs are thus 2.7¢/mile, so I DO recommend EVs as a huge energy and cost saver.

247?? Amazing. My May 2017 S D100 had a lifetime of 316 at 42000 mi. I thought that was pretty good given all the cross country I have done. Many of those miles were in mountains and at 80 mph when that was the speed limit.

I lost the data when I upgraded the MCU a few weeks ago. So now starting the meter over.

But 247? My car is rated at 300... so until now I felt 316 was decent.

I over produce with solar. So charging the car cost 3 cents a kWh, the price the power company pays me for the extra. A good deal for them since they sell it for 19-35 cents....

I was thinking of getting the bumper sticker: my car runs on sunshine.... when I am home... :)
 

RaeW

Member
Apr 19, 2017
98
18
East Falmouth MA
I live on Cape Cod and would pay the same $0.23/kWh were it not for solar panels I installed in 2010. I typically pay three to seven cents per kWh, so I don't mind charging at home even though it increases my electric bill significantly. Prior to charging the 2015 MS 85D at home I paid one to two cents per kWh. I charge at 24 amps (17-18 mph) on a 30 amp 240V circuit. I have a SuperCharger 3 miles away and use it occasionally. Other SuperChargers are not too far away in Hyannis and Wareham. In my case the cost of energy for the Tesla is a bargain compared to an ICE.
 
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Reactions: David29

Raechris

Member
Nov 21, 2017
652
300
Boston
BTW I was just contacted by national grid to join a program to plug in a device to the car so they can better understand EV charging. I hope they are planning TOU billing as they charge .27 kWh now. Program name is SmartCharge.
 

Bill25cycle

Member
Mar 31, 2011
103
69
Last week was the 4th anniversary of the activation of my home charging set-up at my condo, so I thought it would be interesting to see how much energy I had purchased from our local utility, Eversource. (I live in eastern Massachusetts.)

I charge the car (a 2015 70D) with a Tesla Wall Connector connected to a 240 Volts single-phase 50-amp circuit. The cable run from the meter to the Wall Connector is roughly 25 feet. I usually charge at 40 amps.

There is a separate service and electric meter for charging my car, so it is (almost) easy to see how much energy the car consumed. I say “almost” because there was a brief gap in my data for which I made an adjustment. Plus, I have a motion-activated security lamp on the same service. The lamp does not run for very long when it activates, so I decided to ignore the lamp’s energy use, as it would be very small compared to the car’s.

In those four years, the circuit consumed 17,827 kWh, while the car went 41,033 miles. So, based upon these raw numbers, we could say that the car charging (including charging losses plus precooling and preheating) consumed an average of 348.7 kWh/mile driven. That compares to the lifetime average consumption shown by the car in July 2019 as 326 Wh/mile. (I lost my historical data at that time because of a computer repair.)

Unfortunately, that is an incomplete picture, because it does not allow for charging elsewhere, such as use of Superchargers and destination chargers on trips. I do not have very good records of charging away from home. So, I made an estimate of the mileage driven away from home over those four years and decided to allow 1,000 miles per year as a rough but reasonable allowance. So that means the Eversource energy was used for about 37,033 miles. The average energy use then looks like 481 Wh/mile, a much higher figure, and a bit startling. I know that charging losses have been estimated at 10% or so, but this would be quite a bit higher.

Most likely, the largest source of extra consumption is preheating and precooling the car. I tend to use that function quite a lot, because my car is parked outside, winter and summer. The car does not consider the energy used for that in the displayed energy consumption, when the car is connected to shore power. Since the car's heater can operate at as much as 6 kW, prolonged use of preheating in winter can add considerably to total energy consumption. Air conditioning does not consume as much, but even that does add something to energy costs.

At my current average price per kWh of about 23 cents, that translates to approximately 11 cents per mile for energy. That is not much if any savings compared to my previous car, which was a Mercedes that got about 20-23 mpg on premium fuel. Which I why I tell people around here that they should not buy a Tesla, or any other EV, with the goal of saving on energy. (The exception might be if they happen to live in a town or city with a municipal electric department, which typically provides energy at a much lower cost.)

My numbers do contain some assumptions, the most important of which is my allowance of 1000 miles per year for travel charged elsewhere. That may be conservative, and I hope it is, but it is not too far off. In any case, it is worthwhile to realize that charging losses may add to the energy consumption reported by the car. And in my case, preheating and precooling probably contribute substantially to the actual total energy used and the cost of it.

One other point: The precooling and preheating would be a smaller factor in cost per mile if I drove more. But I am retired, so I do not commute. And of course, since mid-March we have been driving very little because of the Covid-19 shutdown.

Hi David -

Is the purpose of the separate service to get a special rate from your Utility? Not sure whom it is, but I know even National Grid (which I have in Buffalo, which charges, including taxes and fees, about 12 cents per kwh after around $18 for the billing charge) charges much more in New England - supposedly since all your electricity generation in the area is high-cost.

If this is a 'discounted' rate - how much is the non-ev electric service? Around my parts, those rates would be considered confiscatory.
 

Bill25cycle

Member
Mar 31, 2011
103
69
Hi David -

Is the purpose of the separate service to get a special rate from your Utility? Not sure whom it is, but I know even National Grid (which I have in Buffalo, which charges, including taxes and fees, about 12 cents per kwh after around $18 for the billing charge) charges much more in New England - supposedly since all your electricity generation in the area is high-cost.

If this is a 'discounted' rate - how much is the non-ev electric service? Around my parts, those rates would be considered confiscatory.
 

StealthP3D

Well-Known Member
Dec 12, 2018
9,386
73,098
Maple Falls, WA
If you ran the engine in the Mercedes to pre-heat and pre-cool the cabin as often as you do in the Model S you would not get 20-23 mpg on premium fuel! Because an idling engine is getting 0 MPG! It also pollutes the neighborhood with noise and toxic fumes. I pre-heat my Model 3 in the winter but it only takes 3-5 minutes (7-10 minutes if in an arctic cold front). I suspect you may be heating and cooling longer than necessary which has added on a huge inefficiency. Also, do you have LED lighting on that motion activated security lamp? Your security light might be using more electricity than you think, especially if it can get tripped by normal neighborhood activity!

I don't know any North American (not in Hawaii or Alaska), that pays $0.23 per kWh for electricity! You are getting ripped off by your utility/wholesalers who must have invested in the wrong energy sources or are regulated by a corrupt utility commission! Electricity should be falling in price in the coming years with cheaper solar and wind steadily increasing and expensive coal falling out of the mix. Maybe you are helping fund inefficient nuclear plants too. I would definitely look into roof top solar because the payback period would be very short (probably less than 10 years)!

I pay 9-11 cents per kWh and the Model 3 is so inexpensive to keep charged I don't even bother to use my free lifetime supercharging even though I drive right by my local Supercharger on a regular basis! Can you imagine someone paying for gas when they regularly drive right by a gas station advertising free gas? Me neither. But electricity is cheap here compared to gas.

Both my Model 3 and my wife's Model 3 charge in our carport that has a dedicated meter. Like your situation, the only other consumption is the overhead lighting. It costs about 1/4 what I would pay for gasoline, on average. But I agree, the gas savings are not what makes the Tesla's so compelling! That would have to be the driving dynamics and everyday convenience of not messing with fueling and oil changes and also the conveniences built into the technology.
 

Vestniek

Member
Nov 22, 2017
51
52
Reston VA
I don't see it mentioned here, so let me point out that the TeslaFi app tracks your car's movements and it's charging very precisely. Superchargers too. You would not need to guess or estimate pre-heat or pre-cooling. If you're into Tesla data, try TeslaFi.
 
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Reactions: eyedub

dmdrums

Member
Mar 13, 2014
24
15
Scottsdale, AZ
The car seems to only account for the energy it "uses" while driving.

In the past 3 weeks, I have only driven my Tesla 40 miles. It was charged to 240 miles and now is has 130 miles left. So....it "lost" 70 miles of range over a 3 week period due to self discharge. That is over 1,200 miles per year (about 3.3 miles per day) of "lost" power that is not counted by the car.

My Lincoln Aviator PHEV uses around 500 Wh/mi. I thought that was bad....but it doesn't seem to lose range when it sits (it must lose some, but it doesn't keep the computer "awake" like the Tesla)

In my case of driving only 6,000 Mi/yr on the Tesla (I know this is not typical), the car is consuming 20% more power than shown on the screen. And that doesn't even figure in the charging losses (another 20%?)

I like the example above with the actual utility meter. That shows the standby losses, charging losses, etc much more accurately.

If it is closer to 500 Wh/mi, then I can drive my PHEV Suv and not feel so bad about it.....

I wish I had a utility meter just for the Tesla. Would be easier to know the "true" Wh/mi

At any rate, I love my car and I have solar. I will keep the Tesla grin and stop worrying about the small stuff....
 

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