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Supercharging newbie question

OK, my free supercharging miles/Kwh have finally been used up (after almost 2 years).

Did my first "paid" supercharging this past week and have a question. When I selected the supercharging location, the car showed a price of .39 per Kwh. (That was a shock, last time I checked it was .29) Did my charging and the screen reported a cost of 10.38 for the charge. When I looked at my actual bill on my account, it showed a price of .36Kwh. The total amount was the same as the car reported though.

3 days later, went to the same supercharger, got my "juice" and the car reported a cost of $5.35. Upon checking the bill, the total amount was the same as reported by the car, but the per Kwh rate on the bill had jumped to .43! I checked the rate shown in the car and it now showed .46Kwh.

Is this variation from the car rate to the actual bill rate normal??

And at these rates, figuring 3 miles per Kwh, the cost per mile of driving is essentially the same as a gas vehicle. Is this an example of Tesla taking advantage of a captive audience? The supercharger is in NY state and looking around the car map display, .46 now seems to be the rate all NY superchargers are charging. I live in NY and have not seen any significant increase in my home electricity rates, but it might be because of the difference of residential rates vs commercial rates maybe? I don't know.

Any clarification on how Tesla sets it's rates would be appreciated.
 

avs007

Active Member
May 14, 2021
1,020
945
PacNW
And at these rates, figuring 3 miles per Kwh, the cost per mile of driving is essentially the same as a gas vehicle. Is this an example of Tesla taking advantage of a captive audience?

3 miles / kWh works out to 333 whm, which seems kind of high... My average is close to 300, and I live on decent sized hill....
But anyways, it depends what car you are talking about in terms of comparing to a gas vehicle... People like throwing out Priuses for comparisons, and point out 50 mpg, but I hate that comparison, becuase a prius is nowhere near the same as a model Y in performance or utility...

An Acura MDX Type-S would be closer to our MY7 in terms of utility and performance, and that thing is only EPA rated 21 mpg... I happen to have an MDX, and when we have 5 passengers in it, the best I can muster on average with that thing around here is 16 mpg. And my Infiniti Red Sport is fairly close to our MY7 in terms of performance, and that thing also averages around 20 something mpg. Even paying 46 cents / kWh, it's still cheaper than gas, compared to these two cars... I don't know how much gas is where you are, but over here it's around $5.59/gallon. Residential electricity is 7 cents / kWh.

But anyways, I imagine most of the time you are charging at home, and hopefully your residential rates are much lower than SC rates?
 
Gas around the upper Hudson Valley is about 4.79, so I guess I should count my blessings. Cost me over $50 to fill up my 2009 Forester yesterday!

Yes, almost all of my charging is done at home and that costs about .16 Kwh (including delivery charges).

My MY is averaging around 265 whm, so I guess I should adjust my mpwh calculation. I use 3 mpKwh as conservative rule of thumb. I too live at the top of a hill. I consistently get to the bottom at around -120whm. Unfortunately, I have to get home, which is up the hill, but it averages out nicely.

But that's kinda besides the point and just a gripe. My question was the variation of the charging rates between the car's screen display and the actual charge rate on my invoice.
 

avs007

Active Member
May 14, 2021
1,020
945
PacNW
I wonder if they just raised the rates in different regions at different times. I just supercharged a few hours ago. Car said 37 cents per kWh, but I was billed 44 cents per kWh. I checked the rates in the car, and saw it said 37 cents. I know it showed 58 cents for the SC near my brother, so I assumed it had all the latest price hikes.
 
Re the Peak rate question - I don't know. There was no indication that there was any "peak" rate was involved, just the normal $1 per minute idle charge. Is there a way to tell? Not having the rate available outside of the car is pretty frustrating.

Taking a look at my bill again (to see if there was a peak rate fee mentioned) I noticed something. When I go into my account and see the listing of my supercharger charges, I noticed that the per Kwh rate is as expected, .39 and .46 respectively. And the math comes out correctly to what I was charged. But looking at the actual invoices, the Kwh rate were reduced, but then adding on the tax that was charged, the total amount was the same as doing the math from the listings. So Tesla must be doing adjustments to the Kwh rate so that the car-posted rate is inclusive of the tax they charge.
 
Re the Peak rate question - I don't know. There was no indication that there was any "peak" rate was involved, just the normal $1 per minute idle charge. Is there a way to tell? Not having the rate available outside of the car is pretty frustrating.

Taking a look at my bill again (to see if there was a peak rate fee mentioned) I noticed something. When I go into my account and see the listing of my supercharger charges, I noticed that the per Kwh rate is as expected, .39 and .46 respectively. And the math comes out correctly to what I was charged. But looking at the actual invoices, the Kwh rate were reduced, but then adding on the tax that was charged, the total amount was the same as doing the math from the listings. So Tesla must be doing adjustments to the Kwh rate so that the car-posted rate is inclusive of the tax they charge.
I bet this SuperCharger does have Peak hours rates. I know many SC in Ca have this and your cost will vary by quite a bit by charging at peak hour.
Bring up the SC on your Tesla nav map and click on the SC. It should give you the rate, and if peak hour rates are being used.
 
I bet this SuperCharger does have Peak hours rates. I know many SC in Ca have this and your cost will vary by quite a bit by charging at peak hour.
Bring up the SC on your Tesla nav map and click on the SC. It should give you the rate, and if peak hour rates are being used.
None of the SC's appear to identify peak rates as a separate line item. They only display one rate and no matter what time of day I've looked, the rate is the same. This is in NY where "time of use" rates are not really pushed as far as I can tell. My local power company has such a convoluted and expensive system for "time of use" that it pretty much makes the plan worthless.

This past week the rates in NY (outside the NYC metro area) varied by a penny .46 vs .45. Next door in Vermont the rates are between .35 and .37
 

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