Charging differences?

[Frankenblob]

I have noticed, as well as those who use chargers and upload those videos, that there is about an 8-10Kw difference in what a charger displays as output and what the vehicle displays on input AND I noticed phones when used also show a 3rd difference.

Anyone know what could be causing such a difference as 8,000-10,000 watts is a fantastic amount.

Those charging stations could face a "class action"...if they are doing any manipulations.

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[Crissa]

Measurements often have differences depending on how you sample the data: Peak, median over time, different time segment, raw power pulled, composite power pulled, and measuring amps isn't in fact something that's done very exactly.

The car's display is probably based off of voltage and an estimate. It won't contain the power lost to heat in the battery, cables, or the other car systems.

The phone's display will probably be a sample over time. It's delayed and sent over a couple networks.

The station, if it has a display, will be raw, and peak. It probably will eventually be the most accurate but Tesla told the state of California that it wasn't yet, and got a two-year reprieve on getting it to have accurate displays.

So there's lots going on here before even talking about the specific tools being used to measure power usage.

My bike, for instance, will be losing about 10-20% inefficiency in the charger.

-Crissa

 

[ajdelange]

I have noticed, as well as those who use chargers and upload those videos, that there is about an 8-10Kw difference in what a charger displays as output and what the vehicle displays on input...

I am not sure which videos are "those" videos but I have certainly never noticed a discrepancy of that magnitude. In level 2 charging there is conversion from AC to DC so it is normal to see about 10% loss with them but with DC fast chargers the losses in the vehicle itself are very low. Now if a Rivian were, for example, charging at 300 kW even 1% loss would be 3kW and quite attention getting. Chargers at those levels lose enough in their cables that liquid cooling is required. I guess the fundamental question is "Who is paying for that lost energy?"

Of course, there is AC/DC conversion loss in Level 3 charging too but it takes place in the cabinets behind the fence - not between the bowser and your battery. I would assume that the metered energy is measured at the terminal and that its stated price includes conversion losses. But bowser cable losses is another question and an interesting one.

 

[Frankenblob]

I am not sure which videos are "those" videos but I have certainly never noticed a discrepancy of that magnitude. In level 2 charging there is conversion from AC to DC so it is normal to see about 10% loss with them but with DC fast chargers the losses in the vehicle itself are very low. Now if a Rivian were, for example, charging at 300 kW even 1% loss would be 3kW and quite attention getting. Chargers at those levels lose enough in their cables that liquid cooling is required. I guess the fundamental question is "Who is paying for that lost energy?"

Of course, there is AC/DC conversion loss in Level 3 charging too but it takes place in the cabinets behind the fence - not between the bowser and your battery. I would assume that the metered energy is measured at the terminal and that its stated price includes conversion losses. But bowser cable losses is another question and an interesting one.

I see, i will let you become "Sherlock Holmes".

 

[ajdelange]

If you want my help you need to make it clear what it is you are talking about.

 

[Frankenblob]

If you want my help you need to make it clear what it is you are talking about.

Here is one :

"Tesla Charging on a CCS 1 DC Fast Charger, Finally" Tom Moloughney -- youtube. at around 9:08 and ends about 9:50.

In the above case the charger said 43Kw output but the car input showed 33Kw.

There are MANY more that do not use that attachment and have similar results, i.e 8-10Kw difference between charger display and vehicle display.

Maybe others here could video what happens to them when they charge up, and whether or not they are experiencing the same, similar or no difference.

Thanks.

 

[ajdelange]

Well that helps to narrow things down quite a bit. That video is about the new SETEC CCS1 to Tesla adapter which is so new that only a few have reached these shores so you shouldn't be drawing conclusions about Rivian charging from this one man's experience with equipment that really has no relevance. Nonetheless it is a simple matter to measured power delivered by the charger on one hand and to the battery on the other. Obviously 30% (43 vs 33 kW) is obviously way too much. There is certainly not 30% loss in a short length of cable nor in that adapter so I think the problem is doubtless attributable to a problem in the dispenser. I say this because there is another video making the rounds here in which a Mach-e is being charged at an EA terminal and there is a discrepancy between the car's display and the chargers. We know there are problems with the EA chargers. As I said above it is trivial to measure voltage and current and multiply them to get power delivered but the multiplication has to be done and the result formatted for display. I'm guessing that the problem lies in the firmware that does that formatting but that is only a guess. Note that there us a 30% discrepancy in the power display but only a 15% discrepancy in the energy reported by the car and the terminal (13 vS 15 kWh). Note that the rounding is to the nearest kWh so the actual numbers recorded by car and terminal might have been much closer than 13 and 15 suggest.

And so we have beta charger and beta adapter. Don't take this too seriously.

 

[Frankenblob]

Well that helps to narrow things down quite a bit. That video is about the new SETEC CCS1 to Tesla adapter which is so new that only a few have reached these shores so you shouldn't be drawing conclusions about Rivian charging from this one man's experience with equipment that really has no relevance. Nonetheless it is a simple matter to measured power delivered by the charger on one hand and to the battery on the other. Obviously 30% (43 vs 33 kW) is obviously way too much. There is certainly not 30% loss in a short length of cable nor in that adapter so I think the problem is doubtless attributable to a problem in the dispenser. I say this because there is another video making the rounds here in which a Mach-e is being charged at an EA terminal and there is a discrepancy between the car's display and the chargers. We know there are problems with the EA chargers. As I said above it is trivial to measure voltage and current and multiply them to get power delivered but the multiplication has to be done and the result formatted for display. I'm guessing that the problem lies in the firmware that does that formatting but that is only a guess. Note that there us a 30% discrepancy in the power display but only a 15% discrepancy in the energy reported by the car and the terminal (13 vS 15 kWh). Note that the rounding is to the nearest kWh so the actual numbers recorded by car and terminal might have been much closer than 13 and 15 suggest.

And so we have beta charger and beta adapter. Don't take this too seriously.

Ok, how about taking notes with your car, it may help.

Double dipping "should only be allowed by Politicians"- hehehe

 

[ajdelange]

Ok, how about taking notes with your car, it may help.

I'm not quite sure what you are looking for here. The car measures the power coming in and the power that is delivered to the battery. In Level 2 charging there will be some loss for conversion from AC to DC and other "losses" to other loads that may be on when the charging is taking place such as HVAC, radio, battery heater etc. The car does take notes and the "efficiency" i.e. the ratio of "energy added" to "energy stored" is generally right around 90%. In Super Charging the same measurements are made but, as there is no (or little) conversion loss in the car itself the ratio is usually pretty close to 100% but if you are running the heater while charging or if the battery needs to be cooled while charging then there will be losses for those and the ratio drops to 95% or so but that's relatively rare. Then there is the measurement made by the terminal itself for billing. It is only fair that one pay for the electricity he takes whether it goes to the battery itself or the cooling of the battery whilst charging. Errors in the measured energy which result in billing errors should not be tolerated and I think we can be sure that just as the electric meters on our home are closely regulated and the dispensers on gas pumps are monitored and regulated so will be the billing circuitry of public recharging stations.

Double dipping "should only be allowed by Politicians"- hehehe

In these parts "double dipping" refers to retired military who go straight into Civil Service and draw their military pensions while getting their GS salary and, ultimately, draw two government pensions. The rules were changed quite a few years ago to make that impossible.

 

[Frankenblob]

I'm not quite sure what you are looking for here. The car measures the power coming in and the power that is delivered to the battery. In Level 2 charging there will be some loss for conversion from AC to DC and other "losses" to other loads that may be on when the charging is taking place such as HVAC, radio, battery heater etc. The car does take notes and the "efficiency" i.e. the ratio of "energy added" to "energy stored" is generally right around 90%. In Super Charging the same measurements are made but, as there is no (or little) conversion loss in the car itself the ratio is usually pretty close to 100% but if you are running the heater while charging or if the battery needs to be cooled while charging then there will be losses for those and the ratio drops to 95% or so but that's relatively rare. Then there is the measurement made by the terminal itself for billing. It is only fair that one pay for the electricity he takes whether it goes to the battery itself or the cooling of the battery whilst charging. Errors in the measured energy which result in billing errors should not be tolerated and I think we can be sure that just as the electric meters on our home are closely regulated and the dispensers on gas pumps are monitored and regulated so will be the billing circuitry of public recharging stations.

In these parts "double dipping" refers to retired military who go straight into Civil Service and draw their military pensions while getting their GS salary and, ultimately, draw two government pensions. The rules were changed quite a few years ago to make that impossible.

I just wanna see when I buy an EV that I am "paying for 150Kw" of output but ONLY getting 120 worth, ya I wont feel ripped off!

 

[ajdelange]

How do you know you aren't paying for 20 litres of petrol but are only getting 18?

 

[Frankenblob]

How do you know you aren't paying for 20 litres of petrol but are only getting 18?

That can be said for anything BUT when the numbers are directly in ones face and one can see, understand and record them then THAT poses a problem to me.

 

[Sirfun]

How do you know you aren't paying for 20 litres of petrol but are only getting 18?

Isn't that what weights and measurement inspectors are for?
Here's the California website: https://www.cdfa.ca.gov/dms/programs/petroleum/petroleum.html

 

[ajdelange]

Yes indeed and I think worry about such things should be left to them!

 

[Crissa]

And metering direct current is not so easy. You can measure it, but like I said, how you measure it and then how you sample that measurement can make a huge difference.

https://electrek.co/2020/01/07/update-californias-ban-on-per-minute-billing-what-you-need-to-know/

-Crissa

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