F150 Real MPGe based on charging from wall outlet

[Roy2001]

Time for the EPA to get rid of the "mpgE" numbers. All I care about are the miles per kWh just like in the cars where the figure of merit was miles per gallon. Does the EPA calculate the energy used to drill for oil, refine it, truck it, pump it, etc? I don't think so. In my case the power comes directly from my solar panels to my car. Yes there's some efficiency lost in charging any battery so that number can be used for calculating costs per mile. Wholesale electricity in PJM interconnect was 4.2 cents per kWh last year- projected to increase to 9 cents per kWh this year. Cost per mile to drive my 2016 F150 is now about 25 cents per mile. Cost per mile to drive my F150 Lightning will be 2.5 cents per mile, maybe double that next year but a huge cost savings over dino-fuel.

MPGe is only for comparison to gas with the same energy.

As consumers, we only care about how many miles we can drive per kWh, so yeah mark that on sticker and specs!

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[vandy1981]

@tommolog says he's getting less than 4% in DCFC losses in his testing. THat's pretty amazing if it holds up in further testing.

 

[Yellow Buddy]

MPGe is only for comparison to gas with the same energy.

I’m not even sure that’s entirely true.

MPG is easy. It’s how much my car consumes to drive a distance. It doesn’t account for infrastructure.

MPGe attempts to count for infrastructure, but there’s so many variables.

At the base of it we can say outlet to car to attempt to capture the cost, but that’s flawed in that your meter isn’t at the outlet and not every outlet is powered the same.

I mean heck Ive sat down and thought about calculating MPGe when I’ve got solar panels at 19.6% efficiency, with optimizers at 98% efficiency, Inverters at 99% efficiency, with a 250ft AC run to my main panel which then does 100ft to my wall charger, that gets 94% efficiency, which then goes into the F150L. Only about 10-12% of the energy that hits my solar panels make it into my EV

What’s my true MPGe in that case?

Then I realize..I don’t really care. I’ll just get more solar when I start getting an electric bill.

 

[Roy2001]

I’m not even sure that’s entirely true.

MPG is easy. It’s how much my car consumes to drive a distance. It doesn’t account for infrastructure.

MPGe attempts to count for infrastructure, but there’s so many variables.

At the base of it we can say outlet to car to attempt to capture the cost, but that’s flawed in that your meter isn’t at the outlet and not every outlet is powered the same.

I mean heck Ive sat down and thought about calculating MPGe when I’ve got solar panels at 19.6% efficiency, with optimizers at 98% efficiency, Inverters at 99% efficiency, with a 250ft AC run to my main panel which then does 100ft to my wall charger, that gets 94% efficiency, which then goes into the F150L. Only about 10-12% of the energy that hits my solar panels make it into my EV

What’s my true MPGe in that case?

Then I realize..I don’t really care. I’ll just get more solar when I start getting an electric bill.

MPG makes sense for gas cars, but MPGe doesn’t for EVs.

MPGe is based on 33.7 kWh electricity which has the same energy as one gallon of gas. So when a car was rated as 68 MPGe, that means it can run for 68 miles with 33.7 kWh it sucked from charger.

It only makes sense in order to compare the efficiency with gas cars. But we all know EVs are efficient. We only care how many miles we can drive per kWh.

 

[beatle]

Some people may care about the overall efficiency of the onboard charger(s) as well, perhaps at different voltages since there is a significant difference, but that'd be easy enough to show. A new standard could show this information:

• City driving wh/mi
• Highway driving wh/mi
• Combined driving wh/mi
• City range mi
• Highway range mi
• Combined range mi
• 240v charging efficiency %
• 120v charging efficiency %

With this data you'd need to do a little math to figure out how much energy you use from the wall to go down the road one mile, but it's better than the current display that shows it the other way around. I also think showing wh/mi is better than mi/kwh since you can have more granular detail about energy consumption without any decimal points. It does require you to think differently about efficiency since higher mpg is always better, and in this case a lower wh/mi metric is better.

 

[SeanOC]

Somewhat off topic but I wish to hell EV manufacturer’s would used a standard method of displaying efficiency. Tesla uses kWh/mi while Ford uses miles per kWh etc.

 

[VTbuckeye]

Somewhat off topic but I wish to hell EV manufacturer’s would used a standard method of displaying efficiency. Tesla uses kWh/mi while Ford uses miles per kWh etc.

Chevy uses mile/kwh. Volvo uses kWh/100miles (which is easy enough to convert to wh/mile).

Also if the charging efficiency at 240V is published we would also want to know the amp while charging (certainly there will be more heat losses at 80amp compared with 40amp and there will be less efficiency at very high states of charge (I'm guessing here but think that charging efficiency would be greater at 40 amp 10 to 80 percent than 80amp 90 to 100 percent).

What driver's really want to know is how far can my car go on xx kWh in the battery (like xx gallons in the tank), not $5 electricity vs $5 gasoline.

 

[FlasherZ]

Chevy uses mile/kwh. Volvo uses kWh/100miles (which is easy enough to convert to wh/mile).

Also if the charging efficiency at 240V is published we would also want to know the amp while charging (certainly there will be more heat losses at 80amp compared with 40amp and there will be less efficiency at very high states of charge (I'm guessing here but think that charging efficiency would be greater at 40 amp 10 to 80 percent than 80amp 90 to 100 percent).

What driver's really want to know is how far can my car go on xx kWh in the battery (like xx gallons in the tank), not $5 electricity vs $5 gasoline.

Don't forget the power consumption of the computers required to monitor charging and the pumps required to circulate coolant during the charge. They're very substantial.

There were several studies done on the 80A Tesla cars in the early days. This is really stretching my recall capabilities, but I think the sweet spot was around 70A or so with properly maintained equipment. Super-slow 120V charging was the worst. 80A wasn't too worse off compared to 70A, but I think it was recognized that your equipment must be very clean to avoid high-current heat losses.

I will say it's been forever since I looked at all those old threads though.

 

[VTbuckeye]

Don't forget the power consumption of the computers required to monitor charging and the pumps required to circulate coolant during the charge. They're very substantial.

There were several studies done on the 80A Tesla cars in the early days. This is really stretching my recall capabilities, but I think the sweet spot was around 70A or so with properly maintained equipment. Super-slow 120V charging was the worst. 80A wasn't too worse off compared to 70A, but I think it was recognized that your equipment must be very clean to avoid high-current heat losses.

I will say it's been forever since I looked at all those old threads though.

Charging for less time may make a difference (computer/battery cooling/heating). I guess that it is time for science experiments.

 

[beatle]

Charging for less time may make a difference (computer/battery cooling/heating). I guess that it is time for science experiments.

Kinda like this experiment?

https://teslamotorsclub.com/tmc/threads/charge-efficiency-chart-from-our-model-3.174044/

Preview: it shows a scatterplot of charging efficiency at different rates. Higher rates (32A - 40A) offered slightly higher efficiency but it wasn't too big a difference. It'll be interesting to see how universal these rates are when compared to the Lightning, and if there are further differences between the single and dual charger efficiency on the Lightning.

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