Mike's monthly Model 3 efficiency report

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Mike

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#61
So I'm clueless why you decide not to plug it in when you arrive.
Call it an experiment.

I'm running the car between 80ish% and mid 50's %.

If that leads to a battery replacement before 8 years/192k km's, so be it.

EDIT: I don't mean to sound flippant with my last statement.

These cars are meant for the "everyperson" and until "everyone" can plug in at all times, there are going to be three or four or five day periods where the car is regularly not plugged in.
 

Mike

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#64
Most EV owners in my neck of the woods simply use the term "juice". Wonder if it's a regional thing?
Some context on why I (used to) use the term "fuel":

I have to choose my grammar for my audience.

I am trying to win over a massive amount of local skeptics.

I find when trying to educate adults, often (not always) one must use the local vernacular when bridging from the known (comfortable) to the unknown (initially uncomfortable).

When they get behind the wheel for the first time, I point to the "fuel" gauge (as an example).

Technically, that is the incorrect term for that icon.

However, one cannot come off sounding like a know-it-all if one wants to win hearts and minds......especially in VERY conservative farm country.
 

tencate

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#66
use the term "juice".
Someone yesterday pointed out to me that "juice" is not terribly different from the unit "Joules" (which can be easily confused for jewels or something for someone who doesn't do science'y stuff). So in keeping with Mike's desire to keep the terms simple, maybe "juice" isn't such a silly term after all although "juice pedal" sounds odd. :)
 

Mike

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#67
Considering the path into the battery and then out the wheels, there are

1) I^2R losses in the conductors along the way - not much, usually, but proper nerds will recognize the evil of a squared term.2) AC to DC conversion loss in the charger - my impression is that this runs about 5-15% - 5% would be an optimistic assumption.3) The round trip efficiency within the battery is less than 100% - I've never encountered a number for this, probably depends on all sorts of things - at least 5% loss is my guess. Perhaps it's as simple as I^2R where R is the battery's internal resistance. Anyway, a battery being charged gets hot!4) Inverter loss - like the charger, these are quoted as something like 5 - 15%, depending on current (better at high rates, though certainly not enough to compensate for aero effects).5) Motor loss(es) - a few percent at least - 5%?6) Gearbox losses - a few percent, maybe. Double for dual-motor
Add them all up and weep. This would be for the simple grid-to-wheels losses, not counting any other energy drawn from the traction battery.
Last night I recharged, from 57% to 92% (459 km indicated on UI when I changed over to distance after the recharge).

Assuming no rounding error existed, the upload of 35% equates to 26.005 kWh net upload of energy (UI says 26 kWh).

Worst case round up/down error from 56.51% to 92.49% equates to 35.98% upload, or a net upload of 26.733 kWh.

However, since the UI said 26 kWh, the max net upload can only be 26.49 kWh.

My Eyedro system states 27.72 kWh gross upload of energy.

With no rounding errors included, this is (27.72/26.005) a 6.6% conversion loss.

With maximum rounding errors included, this is (26.49/26.005) a 1.8% conversion loss.
 

ADK46

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#68
Last night I charged a car that said it had used 28 kWh since its last charge. My meter said it took 38 kWh to charge the car back up to 90%. That corresponds to a 26% loss.

That seems high (probably explained by what the car is actually reporting), but 1.8% seems low.

I just tried to read up on charger efficiencies. There are many confusing articles, so I need to keep reading. But I don't think they get over 95% efficiency.
 

Mike

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#69
Last night I charged a car that said it had used 28 kWh since its last charge. My meter said it took 38 kWh to charge the car back up to 90%. That corresponds to a 26% loss.
That 28 kWh that the car says......that is only when the wheels are actually moving. While at a stop light, that counter stops keeping track.

Your 28% overhead sounds very reasonable for winter time.

My winter overhead last month was over 1.5 times what you got.
 

Mike

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#70
For February 2019:

kwh-inputs-feb2019-png.22585


real-kwh-upload-totals-feb-2019-png.22590

*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.

For February 2019, the total overhead was 32% greater than the odometer reading.

Two long distance trips this month are the reason the figure is much better than January, which had local short trips only.

Raw data:



So with any decent long distance driving, the winter overhead in this car is about double the summer overhead.

Total operating costs summary:

summary-feb2019-png.22591
 

Mike

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#71
For March 2019:

capture_raw_data-png.24175


capture_real_upload_diff-png.24176

*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.

For March 2019, the total overhead was (only) 26% greater than the odometer reading.

Moderating temperatures, plus two long distance trips add up to numbers trending back to summer figures.

Raw data:



Total operating costs summary:

capture_summary-png.24180


The "purchase" total increased from last month ($80,251.68) to reflect the addition of Full Self Driving.

With 10 months of data, as depicted in "Electricity Summary" (from "at the meter"), my car has achieved 192 Wh/km (310 Wh/mile).
 

Mike

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#72
For April 2019:

capture-raw-data-png.25429


capture-real-upload-png.25430


*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.

For April 2019, the total overhead was up again to 38% greater than the odometer reading.

Although the moderating temperatures continue, this month was all short trips that averaged less than 8 km.

Raw data:



Total operating costs summary:


capture-summary-png.25434



With 11 months of data, as depicted in "Electricity Summary" (from "at the meter"), my car has achieved 192.5 Wh/km (312 Wh/mile).

Over those same 11 months, the car odometer has shown 3652 kWh used over the 23,474.3 kms.

This "car odometer figure" (energy used only while vehicle is underway) is 154.4 Wh/km (250 Wh/mile).
 

DanSz

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#73
When you hit the 12 month mark, I’d like to see a graph of the two efficiency numbers: Car whr/km and real wh/km vs month.
 

Mesprit87

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#75
Might have something to do with the hard time we get getting it to sleep. My guess is that the latest loads didn't help the matter.
What matters to them (the manufacturers) is obviously power consumption while running. The whole EV market doesn't what to share the costs of vampire drain or just plain power requirements at idle and even if they would, it would be impossible because every car will live in a different environment.
 

DanSz

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#76
Customer complaints about dead cars from parking at airports will help OEMs care about vampire drain. Airplane parking mode would be nice or simply super deep sleep after 48hrs would be nice.

OEMs call these “walk homes”, when a car doesn’t start (or go). They are very damaging to customer feelings of a quality car when under warranty.
 

Mike

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#77
May 2019 results (have had the car 12 months):

capture-raw-data-png.26411


capture-real-upload-png.26412


*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.

For May 2019, the total overhead was down to 20% greater than the odometer reading.

This month included a 15 day period where the car was parked, not plugged in (or disturbed) and lost (only) 8% SOC over said 15 day period.

Raw data:



Total operating cost summary:


With 12 months of data, as depicted in "Electricity Summary" (from "at the meter"), my car has achieved 191.1 Wh/km (310 Wh/mile).

Over those same 12 months, the car odometer has shown 3899 kWh used over the 25,371 kms.

This "car odometer figure" (energy used only while vehicle is underway) is 153.7 Wh/km (249 Wh/mile).

Bottom line: with one year of data, my correction factor (yearly average) to whatever the car odometer reading says is 24%.
 

Mike

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#78
June 2019 results:

jun2019_captured-raw-data-png.27233


jun2019_captured-real-upload-png.27234


*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.

For all intents and purposes, the overhead for June 2019 is the same as June 2018.

Raw data for June 2019:



Summary costs as of 30 June 2019:

jun2019_captured-summary-png.27238


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

$3.0278 - $2.8766 = $0.1512/km

Discussion:

In Sept 2018 (first archived capture), the total operating costs, per km, were $0.2644
In Jan 2019, the total operating costs, per km, were $0.1956
In May 2019, the total operating costs, per km, were $0.1611
In June 2019, the total operating costs, per km, were $0.1512
 

Mike

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#79
July 2019 results:

jul2019-raw-data-png.28030


jul2019-real-upload-png.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:



Summary costs as of 31 July 2019:

jul2019-summary-png.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.
 
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