Mike's monthly Model 3 efficiency report

Mike

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#82
July 2019 results:

View attachment 28030

View attachment 28031

*please pardon the use of "'s" after kWh in these data base column titles, long story short I can't edit them out until further notice.

Discussion: almost 50% more "overhead" than July 2018. IMO the majority of this is because I only drove 57% of the distance I did in July 2018. The minority of this is the use of sentry mode everywhere except at home plate.

Raw data for July 2019:

View attachment 28032 View attachment 28034 View attachment 28033

Summary costs as of 31 July 2019:

View attachment 28035

Total operating costs, per km (total costs minus capex costs):

$2.8837 - $2.7040 = $0.1797/km

Discussion:

In June 2019, the total operating costs, per km, were $0.1512

The higher costs per km July figures includes another years worth of automobile insurance, which will be smoothed out over the next few months.
Another reason why my overhead is higher now than July 2018: after shut down the HVAC will go thru it's song and dance to dry out the evaporator core, thus adding another parasitic drain not factored into the cars odometers.
 

JDM3

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Another reason why my overhead is higher now than July 2018: after shut down the HVAC will go thru it's song and dance to dry out the evaporator core, thus adding another parasitic drain not factored into the cars odometers.
Ahh, so that's what that was. I was wondering why the car's fan seemed to be going nuts after parking. Learn something new every day.
 

Dr. J

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#84
Another reason why my overhead is higher now than July 2018: after shut down the HVAC will go thru it's song and dance to dry out the evaporator core, thus adding another parasitic drain not factored into the cars odometers.
I don't know what it takes to run that fan, but I'm betting the use of Sentry mode is the more significant factor, by....a factor of something.
 

Mike

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I don't know what it takes to run that fan, but I'm betting the use of Sentry mode is the more significant factor, by....a factor of something.
I don't know either, it's just my hypothesis.

When that HVAC fan runs and I am plugged in, the car is NOT using shore power (which I can meter), so for now it is an unknown.
 

Dr. J

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I don't know either, it's just my hypothesis.

When that HVAC fan runs and I am plugged in, the car is NOT using shore power (which I can meter), so for now it is an unknown.
I would call on @JWardell and @garsh to opine on the energy consumption of the HVAC fan at the end of an air conditioning session.
 

JWardell

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I would call on @JWardell and @garsh to opine on the energy consumption of the HVAC fan at the end of an air conditioning session.
I think shore power only kicks in if high voltage is being used...that is when the AC compressor or heater core are used. The fan is just 12v so I don't think it will pull from the charger just to blow air.
 

MelindaV

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#88
based on my car, the total vampire drain for the month only cost me $4.20. that is with sentry on everywhere but home, AC COHP on, starting the AC every day I walk out of my office, often leaving the AC on when doing errands and knowing I'll be inside for up to an hour and parked in the sun, plus all the little things.
IMO, $4 is totally worth all of those things that causes the drain.
 

Dr. J

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#89
based on my car, the total vampire drain for the month only cost me $4.20. that is with sentry on everywhere but home, AC COHP on, starting the AC every day I walk out of my office, often leaving the AC on when doing errands and knowing I'll be inside for up to an hour and parked in the sun, plus all the little things.
IMO, $4 is totally worth all of those things that causes the drain.
Impressive, but...
End of the month info for July!
.....
Average temperature: 74
Whereas:
Our average LOW temperature for the month of July is 74.6. So maybe the cooling drain varies by climate.

Or were you stating your cabin interior temperature setting? :D
 

MelindaV

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Impressive, but...

Whereas:
Our average LOW temperature for the month of July is 74.6. So maybe the cooling drain varies by climate.

Or were you stating your cabin interior temperature setting? :D
my car still sits in the full sun each mid day in 80-95 afternoon temps - without cohp, the interior temps are in the 120s+ so there is still work for the cohp even with lower temps.
 

Mike

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#91
based on my car, the total vampire drain for the month only cost me $4.20. that is with sentry on everywhere but home, AC COHP on, starting the AC every day I walk out of my office, often leaving the AC on when doing errands and knowing I'll be inside for up to an hour and parked in the sun, plus all the little things.
IMO, $4 is totally worth all of those things that causes the drain.
Question for you @MelindaV, are you tracking what is drawn from the grid directly (such as a seperate meter on your wall connector circuit) or are you using odometer numbers and UI indicated kWh uploaded numbers to infer your kWh overhead?

I looked at your linked page.

If your figures are from the grid to your car, then your overhead of only (53.06/330.6) 16% for 1204 miles with 230 Wh/m makes my July figures (30% overhead with 1128 miles and 210 Wh/m) look WAY out of whack.

Please use suitable 2x4 to bop me on the head as required, but your (1204 x .230) 330.6 kWh sounds like data from the car odometer.

My car only runs sentry, at best, 1.5 hours a day. I never use cabin overheat. In the summer, I am finding the HVAC set to 24c as sufficient to cool the car. My odometer says .210 Wh/mile for the month............
 

MelindaV

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Question for you @MelindaV, are you tracking what is drawn from the grid directly (such as a seperate meter on your wall connector circuit) or are you using odometer numbers and UI indicated kWh uploaded numbers to infer your kWh overhead?

I looked at your linked page.

If your figures are from the grid to your car, then your overhead of only (53.06/330.6) 16% for 1204 miles with 230 Wh/m makes my July figures (30% overhead with 1128 miles and 210 Wh/m) look WAY out of whack.

Please use suitable 2x4 to bop me on the head as required, but your (1204 x .230) 330.6 kWh sounds like data from the car odometer.

My car only runs sentry, at best, 1.5 hours a day. I never use cabin overheat. In the summer, I am finding the HVAC set to 24c as sufficient to cool the car. My odometer says .210 Wh/mile for the month............
I'm using the consumption numbers from the car and the charging numbers from Teslafi to calculate the difference between what goes into the car vs what it takes to propel it. So my numbers would be missing what happens between the panel and electricity getting to the car, but the API does include Used and Added, and I use the higher number, so possibly, the API is calculating the energy when it hits the Wall Connector (used) and when it hits the battery (added). Or more likely, the used includes any conditioning that is happening at the time of charge, and added is the actual energy added to the battery.

Screen Shot 2019-08-03 at 2.23.31 PM.png
 

Mike

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#93
I'm using the consumption numbers from the car and the charging numbers from Teslafi to calculate the difference between what goes into the car vs what it takes to propel it. So my numbers would be missing what happens between the panel and electricity getting to the car, but the API does include Used and Added, and I use the higher number, so possibly, the API is calculating the energy when it hits the Wall Connector (used) and when it hits the battery (added). Or more likely, the used includes any conditioning that is happening at the time of charge, and added is the actual energy added to the battery.

View attachment 28105
Hmmmmm......

I'll have to ponder this on my Bowling Green KY to Southfield MI run tomorrow.

I'll hopefully have some intelligent follow up questions once I can think it thru.......
 

Mike

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#94
I'm using the consumption numbers from the car and the charging numbers from Teslafi to calculate the difference between what goes into the car vs what it takes to propel it. So my numbers would be missing what happens between the panel and electricity getting to the car, but the API does include Used and Added, and I use the higher number, so possibly, the API is calculating the energy when it hits the Wall Connector (used) and when it hits the battery (added). Or more likely, the used includes any conditioning that is happening at the time of charge, and added is the actual energy added to the battery.

View attachment 28105
In your above example, what does the (charge efficiency) 95.8% represent/come from?

Or, put another way, I can't get 7.6 and 7.33 to come together and spit out a value of 95.8%.

It's too bad no one has a seperate meter (for raw charging to the car data) and Teslafi (to run a charge session and see if the numbers are the same).
 

MelindaV

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In your above example, what does the (charge efficiency) 95.8% represent/come from?

Or, put another way, I can't get 7.6 and 7.33 to come together and spit out a value of 95.8%.

It's too bad no one has a seperate meter (for raw charging to the car data) and Teslafi (to run a charge session and see if the numbers are the same).
I assume its mostly rounding errors with small numbers, especially with the 'Used" only giving one decimal point, while the "added" two. and assume these are numbers pulled from the API. I don't think Teslafi does any calculating, but just shows the info the car records.
here's a couple other examples where the math works out closer ;)
Used 11.5kWh, Added 11.52kWh, Charging Efficiency 100.5% (figure that one out)
Used 73.9kWh, Added 68.91kWh, Charging Efficiency 93.2%
Used 31.8kWh, Added 30.38kWh, Charging Efficiency 95.4%
Used 39.3kWh, Added 34.98kWh, Charging Efficiency 88.9%
Used 21.2kWh, Added 20.10kWh, Charging Efficiency 95%
 

Mike

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#96
I assume its mostly rounding errors with small numbers, especially with the 'Used" only giving one decimal point, while the "added" two. and assume these are numbers pulled from the API. I don't think Teslafi does any calculating, but just shows the info the car records.
here's a couple other examples where the math works out closer ;)
Used 11.5kWh, Added 11.52kWh, Charging Efficiency 100.5% (figure that one out)
Used 73.9kWh, Added 68.91kWh, Charging Efficiency 93.2%
Used 31.8kWh, Added 30.38kWh, Charging Efficiency 95.4%
Used 39.3kWh, Added 34.98kWh, Charging Efficiency 88.9%
Used 21.2kWh, Added 20.10kWh, Charging Efficiency 95%
Double hmmmmmmm..... :)

Anyone watching this thread that uses Teslafi has a free charging session waiting for them at my place, where my dual meters on my charge circuit can compare to what Teslafi says.

Yes. Really.