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Supercharging costs discrepancies (Display vs Bill from Tesla)

wk057

Vendor & Senior Tinkerer
Feb 23, 2014
5,713
11,963
Hickory, NC, USA
Hi all,

I've done eight paid supercharger sessions with the Model 3 so far.

7 out of 8 times, the display showed the final cost of the charge at least one unit (kWh or minute) less than the actual bill I get from Tesla.

So, just wondering if anyone else has noticed this. Probably just some software bug, but would be nice if they matched.

-wk

P.S. - ~1200 mile supercharger enabled trip - $40.
 

CUBldr97

Member
Apr 20, 2015
398
250
MD
what has tesla said about that?
3.3 cents per mile, nice

what was your trip watts per mile? and if you can brake down the super charger charge cost, and kwh etc? for those of us who have not used the pay service yet?
 

wk057

Vendor & Senior Tinkerer
Feb 23, 2014
5,713
11,963
Hickory, NC, USA
what has tesla said about that?

No response my first email note about it from the first time it happened a few weeks ago.

3.3 cents per mile, nice

what was your trip watts per mile? and if you can brake down the super charger charge cost, and kwh etc? for those of us who have not used the pay service yet?

I plan to do another post at some point in the near future about this, along with all of my impressions of the 3 after over a month and 3000 miles of driving.

Forgot to attach these images to the first post:
2018-03-30%2000.38.36-1080.jpg


And the receipt I got from Tesla for that session:
supercharger-receipt.jpg
 

Hans L

Member
Aug 17, 2017
156
172
San Diego
Did you have set anything up in your Tesla account to access the Superchargers? I don't believe I have my CC stored in my Tesla account...but maybe I do...I should check.
 

siai47

Member
Jan 23, 2014
165
190
Deland, Fl.
I think the billing for the Supercharger session might be more exact than the display on the car. If you watch the in car display during the Supercharger session, you will see that (at least in my car) it updates in increments of 3 KWh. I tried timing the session and terminated it just prior to the next update to the display. As I expected, the billing was higher than the number shown on the vehicle display by a couple of KWh. Anyway---sounds like a good answer to the OP's question. BTW---I didn't receive an invoice from Tesla, just a CC charge to a card I have on file with them.
 
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swaltner

Active Member
Oct 13, 2012
1,621
1,653
Kansas, USA
This makes sense because doesn’t the instrument cluster on the Models S also display energy gained from regenerative braking in 3 mile increments?
 

eHeyMan

Member
Sep 29, 2015
15
5
WA
I've noticed this too. Has anyone got an explanation from Tesla? Comment by siai47 makes sense. I have a difference of $0.11 and $0.33 more on CC bill from February Supercharger stops in WA (before the rate increase). I believe the rate was $0.11 then.
 
Oct 12, 2016
1,086
962
MD
Is there a section on our tesla account online where we can find the aggregate supercharger costs? Where do you look for your costs?
I just took a 2k mile trip in the 3.
 

bnsfengineer

Member
Aug 25, 2017
741
294
So.Ca.
Did you have set anything up in your Tesla account to access the Superchargers? I don't believe I have my CC stored in my Tesla account...but maybe I do...I should check.
I don't either and have used twice...I believe if no credit card it just stays on your account?
 

bnsfengineer

Member
Aug 25, 2017
741
294
So.Ca.
No response my first email note about it from the first time it happened a few weeks ago.



I plan to do another post at some point in the near future about this, along with all of my impressions of the 3 after over a month and 3000 miles of driving.

Forgot to attach these images to the first post:
2018-03-30%2000.38.36-1080.jpg


And the receipt I got from Tesla for that session:
supercharger-receipt.jpg
Where did you get the receipt from?
 

lonewolf313

Member
Jun 18, 2014
242
79
Sydney Australia
Hi all,

I've done eight paid supercharger sessions with the Model 3 so far.

7 out of 8 times, the display showed the final cost of the charge at least one unit (kWh or minute) less than the actual bill I get from Tesla.

So, just wondering if anyone else has noticed this. Probably just some software bug, but would be nice if they matched.

-wk

P.S. - ~1200 mile supercharger enabled trip - $40.

So the car registered 48 kWh going into the battery and the Supercharger has registered 50 kWh

It appears that there is a 2kWh power transfer loss through the Supercharger cable.
 
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wk057

Vendor & Senior Tinkerer
Feb 23, 2014
5,713
11,963
Hickory, NC, USA
So the car registered 48 kWh going into the battery and the Supercharger has registered 50 kWh

It appears that there is a 2kWh power transfer loss through the Supercharger cable.

It happens on timed (bill per minute) sessions also, and is independent of charge time (losses would be more for a longer session, for example).
 

Chewy3

If MacGvyer had a beard
Apr 30, 2016
355
813
San Diego
So the car registered 48 kWh going into the battery and the Supercharger has registered 50 kWh

It appears that there is a 2kWh power transfer loss through the Supercharger cable.
This makes sense that the Supercharger is recording 1 amount (50kWh) because that is what it is pushing out, and the car is recording another (48kWh) because that is the amount it is actually receiving. However, I would assume they talk to each other.
 

AWDtsla

Active Member
Mar 3, 2013
4,266
3,960
NE
This makes sense that the Supercharger is recording 1 amount (50kWh) because that is what it is pushing out, and the car is recording another (48kWh) because that is the amount it is actually receiving. However, I would assume they talk to each other.

Any reason to believe the supercharger even knows how much it's delivering? If it did, surely it would measure the draw from the circuit, which would be around 10% higher than what's delivered to the car.
 

Chewy3

If MacGvyer had a beard
Apr 30, 2016
355
813
San Diego
Any reason to believe the supercharger even knows how much it's delivering? If it did, surely it would measure the draw from the circuit, which would be around 10% higher than what's delivered to the car.
I've never met a power supply that didn't know how much juice it was putting out.
 

Chewy3

If MacGvyer had a beard
Apr 30, 2016
355
813
San Diego
I've met plenty.
Sure, if we are talking low power and fixed outputs.

But Tesla Superchargers provide variable output power up to 145kW, any system close to that much energy is going to have self-monitoring functionality as a safety precaution alone.

Can I prove it? Nope, I don't work for Tesla and don't have the time to research the build permits.
 
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