Mike's monthly Model 3 efficiency report

Mike

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#1
I figure I have enough data points now, so at the end of every calendar month I'll just post these two (screen shots) pages of spreadsheet numbers as time goes by.

I reset odometer number one (titled "Current Hydro Billing Cycle") and my stand alone hardwired power/energy meter (that monitors my Tesla Wall Connector) at the end of each monthly cycle after logging the data.

Any supercharger/hotel/other energy downloads are logged throughout the month and are included in these numbers.

Enjoy.

Odometer 1 versus raw data, energy uplift:

odo1readings-png.15310

In my situation, the total delta between the car's odometer (watts/km) versus logged total energy uplift was 17% for September 2018.

Totals (as of 30 Sep 2018, all figure $CDN):

summarypage-png.15311
 

Mike

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#2
Happy Halloween.

My numbers for October 2018:

Odometer 1 versus raw data, energy uplift:

capture1-png.16880


In my situation, the total delta between the car's odometer (watts/km) versus logged total energy uplift was 18% for October 2018, a slight increase from the 17% delta last month.

Not surprisingly as I am using the heated seats all the time as well as cabin heat at 19.5c (manual, fresh air only, fan speed one, airflow to windscreen and central area).

Totals (as of 31 Oct 2018, all figures $CDN):

capture2-png.16881


My cost for fuel per km still holding at 2.9 cents per km.

Interesting to note: the interest paid on my 48 month loan already exceeds the total fuel cost.

:)
 

MelindaV

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#5
Not surprisingly as I am using the heated seats all the time as well as cabin heat at 19.5c (manual, fresh air only, fan speed one, airflow to windscreen and central area).
it has not really gotten cold here yet (average highs in mid 60sF to low 70sF) but may try to switch from auto to manual speed 1 and see if there is any notable change in Wh/mile over auto fan speed (which generally is 1-3).
 

Mike

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#7
it has not really gotten cold here yet (average highs in mid 60sF to low 70sF) but may try to switch from auto to manual speed 1 and see if there is any notable change in Wh/mile over auto fan speed (which generally is 1-3).
The biggest thing with manual is you can always force fresh air.

That alone will keep your windows defogged with much less airflow required.
 

Mike

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#8
Why are you measuring "Mileage Summary" when your accounting is in km?
Is "kilometrage" a word?
-chris
Kilometerage shows as a "new word suggestion" when doing the Google thing.

I think it sounds crappy and I think everyone seems to understand the concept when the term "mileage"is used. :p
 
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#10
the correct term is "consumption" as we display how much fuel we need to go a given distance. This makes much more sense due to there being a linear relationship as opposed to mpg which makes no sense at all. Your dial starts at infinity and then the higher the dial goes the smaller the number gets. Who came up with this??

Kilometerage would be km/litre which noone uses because outside america people use units which are easy to use and understand.
 

Nom

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#11
Hi - love seeing this data. Kinda new to it though. Just to be clear though ... columns D and F should be labelled watts-hours / kilometer. Not kilowatt-hours / km. Seems like the numbers are a factor of a 1000 off if it is meant to truly be kwh/km. Will keep digesting it .... Again, thank you for posting!!
 

Nom

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#12
Hmmm, any thoughts on the discrepancy between what your Tesla is saying and what your energy meter is saying with regards to power uploaded? 18% discrepancy isn't minor.
 

Mike

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#13
the correct term is "consumption" as we display how much fuel we need to go a given distance. This makes much more sense due to there being a linear relationship as opposed to mpg which makes no sense at all. Your dial starts at infinity and then the higher the dial goes the smaller the number gets. Who came up with this??

Kilometerage would be km/litre which noone uses because outside america people use units which are easy to use and understand.
Here is my re-labeled summary tab:
capture-png.17013

The change (circled in yellow) is to clarify that the data is all tied to "distance driven" and the other term was a relic of when the basis of this particular spreadsheet first came into being, back in 1991(!).

Hi - love seeing this data. Kinda new to it though. Just to be clear though ... columns D and F should be labelled watts-hours / kilometer. Not kilowatt-hours / km. Seems like the numbers are a factor of a 1000 off if it is meant to truly be kwh/km. Will keep digesting it .... Again, thank you for posting!!
Cheers and thanks for the catch!

Here is the corrected tab:

capture2-png.17014

Hmmm, any thoughts on the discrepancy between what your Tesla is saying and what your energy meter is saying with regards to power uploaded? 18% discrepancy isn't minor.
Obviously, I'm only going to deal with how much hydro I actually have to feed this car, so that is why (from a cost perspective) I deal only with "well-head to wheels" (sorry).

And just like the whole liquid fuel distribution system, there are some losses we have to deal with.

First loss is what is surmised to be a 5% loss at the AC/DC conversion point inside the actual on board charger.

Second loss "I think" may be related to the "vampire drain", estimated at 1%/day.

Since I can tap into 74.3 kWhs of the actual battery capacity, 1% of that works out to 743 watts/day.

A notional month has 30.34 days in it, so a notional monthly vampire loss adds up to 22.542 kWhs of energy not providing actual energy services.

The %/month of vampire drain is inversely proportional to how much driving you do (i.e. more driving = less losses with the car just sitting there).

In my example for October 2018, the car says I uploaded 388 kWhs and 22 kWhs of estimated vampire losses would work out to about 5.5% loss.

The only thing I can't get my head around on this one (yet) is the upload listed in the car "should" deal with this, but I have some suspicions (I'll detail below).

The third loss is the actual 3.4 watts (nominal) that my Tesla Wall Connector requires to sit there and be ready.

That math works out to 2.48 kWhs a month.

Not much, but a little over 0.5% loss.

Fourth loss deals with things like HVAC use, and this goes back to my suspicions mentioned above.

If one were to sit in a Model 3 and crank up the heat and let that car heat up until its too hot to sit in WITHOUT putting it into gear to drive the wheels, logic would dictate that the watt/hours per km would start to increase.

It doesn't.

I've tried this numerous times and I have come to the conclusion that the number on the trip odometer is only calculated while the car is in gear and actually driving.

If you sit in a traffic jamb for say 10 minutes on some freeway, watch that number.

It should climb, but it doesn't.

The % battery level drops, which is logical because you are using energy to keep things warm/cool inside your car.....but the rear wheels aren't rotating.

Anyhow, sorry for the long drone.......I hope that answers your question.....what was it again? o_O
 

Mike

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#17
Over $0.17 CDN/Kwh?
That cost is electricity from all sources, including superchargers on my various road trips.

My cost at home for off rate, Oct 2018, including all taxes, fees and surcharges, is 13.2 cents per kWh.

The actual commodity (off rate) is 6.5 cents per kWh.

That seems really expensive for what's mostly hydro
Unfortunately, in Ontario, the major cost driver is our nuclear fleet, which provides about 60% of our total production.
 

Mike

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#18
It's only mid month, but I am noticing the day by day spread between what the car says (has been used) and what my independent meters say (has been uploaded) is increasing.

13 Nov 2018, for example:

The car says 9 kWhs was consumed for providing 58.2 kms of propulsion:

img_0103-jpg.17570


My Eyedro meter shows 12.443 kWhs uploaded to refill the propulsion battery back to my standard "first thing in the morning" indicated (80%) level:

13nov2018-actual-upload-png.17571


The previous months leading up to cold weather ops showed a 17% spread between the car odometer energy use numbers and the true uplift numbers.

On 13 Nov 2018, the difference was (12.443/9) 38%.

Assuming 17% "loss" is normal for warm operations, it is appearing that cold weather ops (garage at 8c, outside temps range +5c to -5c) may show another 20% "loss".

Again, one data point only, however even at 8c in my garage for 22 hours a day, some battery conditioning is obviously taking place.

We'll see what the end of month numbers actually work out to.
 

Trevlan

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#19
So what do you actually figure it costs to charge at night, let’s say if you were to put back 50% 30% going to 80% charge for a 50% charge?

Thanks for all the data
 

Mike

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#20
So what do you actually figure it costs to charge at night, let’s say if you were to put back 50% 30% going to 80% charge for a 50% charge?

Thanks for all the data
Cheers and welcome to the forum @Trevlan.

I don't have access to my laptop and its hard data numbers right now, but some back of napkin math should be close enough.

If the charge event is one night (i. e. start charge at 0200, complete at 0520 and then drive later that day so no need to deal with vampire losses), then........

I have access to 74.3 kWhs of stored energy in this battery pac, so 50% of that is 37.15 kWhs.

For my current hydro billing cycle (because distribution costs change month to month based on usage), my off peak (middle of the night) rate, with all taxes, fees and surcharges works out to 13.2 cents per kWh.

$ 0.132 x 37.15 = $4.90.

Add about 5% to that for conversion losses and I get $5.14.

So, five bucks :)