Supercharging costs discrepancies (Display vs Bill from Tesla)

[mongo]

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.

The Supercharger can measure current output directly along with voltage at its terminals. What it can't measure directly (unless there are remote sense wires which does not look like the case based on internal photos) is the voltage at the vehicle/ pack. Unless the vehicle reports its internal voltage sense value back specifically for this purpose, the Supercharger is going to bill based on gross power delivered.

Time of use could vary based on time start/end triggers, display rounding, and such.

 

[Boourns]

Just to make sure my car could supercharge correctly, I tested it the other day. Stayed 10 minutes, and the car reported the cost as 90 cents. My bill was for $1.30. Obviously not a big deal, but over the long term a 40-plus-percent discrepancy seems high.

 

[mongo]

Just to make sure my car could supercharge correctly, I tested it the other day. Stayed 10 minutes, and the car reported the cost as 90 cents. My bill was for $1.30. Obviously not a big deal, but over the long term a 40-plus-percent discrepancy seems high.

Beware of fixed (or at least bounded) vs proportional errors when dealing with small numbers. Your numbers also support a 4.4 minute offset which would be a lesser percentage at larger time.

Your offset is quite close to wk057's image (0.40 vs 0.42) maybe there is a flat base fee (that is rolled into the unit rate)?

 

[Maynerd]

Did a supercharger on 04/01 my car stated I was billed $14.75 but my CC shows a charge of $15.50 Dunno why there's a discrepancy.

 

[Krash]

 

[BlueWRXPride]

Perfect - thanks!

I don't see anything that says History in my account. I have used a supercharger once and do have a card on my account, but it wasn't charged. And this was a week ago.

 

[lupend88]

I supercharged in Monterey CA last week, gained about 200 miles and on my display Tesla only charged me $0.52 and I was thrilled, I thought it was a glitch in my favor. Checked My Tesla account that afternoon and it showed $15.86. Big discrepancy there.

 

[MacGreiner]

I don't see anything that says History in my account. I have used a supercharger once and do have a card on my account, but it wasn't charged. And this was a week ago.

 

[BlueWRXPride]

View attachment 315222

Yeah, that doesn't show up for me...

 

[SigNC]

It won't show up until something hits your account. At least that's how it was for me.

 

[gambit48]

At least yours is consistent. Mine sometimes has the correct price (or very close to it). Other times, it'll say like $1.56 when it should be above $10. Seems random. I can't find the actual price until I log onto a desktop/laptop.

 

[wk057]

Lately my supercharging sessions with the Model 3 just haven't been showing up on the Tesla site at all about 50% of the time. I owe them about $20 in unbilled sessions so far.

 

[FalconFour]

Wow, amazing this has gone on this long. Yeah, there's a discrepancy there. And to be clear, my point isn't about pennies, but about principle.

Both the Model 3 and the Supercharger stations are marvels of design and engineering, hyper-connected and always-on. So, the fact that the Supercharger (and Tesla) bills a different amount from what's shown in the car is utterly insane and somewhat unbelievable to me, that Tesla could put this kind of flawed system out there - particularly on a subject as sensitive as billing. The car could simply ask Tesla (via the !wow! Internet!) how much the bill is, or was, and display that on the screen.

Yes, I think we'll all forgive slight discrepancies. But there are so very, very many ways to fix (or simply avoid) problems like this in the first version... simply say "estimate" in the car, have a link to billing history in the app... display the Supercharger pricing on every station details pin... real easy things, first-rev "MVP" things.

Now we're here, 4 months or so since OP, and it's still exactly as flawed now as it was then.

Again, this is about principle, not pennies. I don't care about the money, I care about the principle of these kinds of gaping holes.

BTW, the "History" link is what I'd refer to as a "hidden menu" in the Tesla site. You have to go back to the main page - if you go to "tesla.com" and follow the flow directly from that page (not a bookmark/recents URL), the first page after log-in is where you find the "history" link. It's hidden away, for sure. Or just use this link -> Payment History | Tesla

 

[tivoboy]

I've never seen more than about .35$ in difference between the car reporting and the online cost or credit card cost. Part of me thinks they are adding some CC processing fee or they are just rounding the kw used UP to the next kw.

 

[Marsnaut]

During one trip, it showed $1 (or $3, I forget) on my screen but in reality it was $11.50. I knew $1 was too low considering I charged almost 200 miles.

It was funny though as my friends always chip in to pay for "gas" during our road trips.

 

[FalconFour]

I'll add that this has nothing to do with CC processing (neither as a fee, nor as a preauthorization) or taxes, as you can go to the History page and see that the only thing they charge for is kWh. (or in other less forward-thinking states, they have to charge for minutes). They just don't charge the same number of kWh that the car shows. Which is a big ole' floppy stinking stupid kind of problem to have.

 

[MrRandyB]

I had heard that the cars update in 3kWh periods.

So if you charge 10kWh, the car will show 9kWh until you hit 12kWh. If you stop the car does not update but the final bill is exact.

Not sure how true this is or if it makes sense but I read this somewhere and it may account for the change differences.

 

[CricTic]

People theorizing WHY the displayed charge may be a few kWh off are missing the point. The vehicle should sync with Tesla the moment the driver disconnects the supercharger and display the correct amount on the screen. If ChargePoint etc can do this, so can Tesla.

If they can't prioritize fixing this due to other things, they should remove the estimate or put ESTIMATE next to it.

 

[AWDtsla]

People theorizing WHY the displayed charge may be a few kWh off are missing the point. The vehicle should sync with Tesla the moment the driver disconnects the supercharger and display the correct amount on the screen. If ChargePoint etc can do this, so can Tesla.

If they can't prioritize fixing this due to other things, they should remove the estimate or put ESTIMATE next to it.

I wouldn't exactly use Chargepoint for a model of how to do software. They've had lots and lots of problems.

 

[CricTic]

At least the billing is right (the 2 times I used it )