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MPGe accuracy


Euclid's Brother
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So, the standard MPGe calculation is not a very accurate way to compare with non EV cars.  33.7 is the accepted factor, so (33.7/kwh)*miles gives the standard MPGe.  That was true when gas prices were around 3.71 and you had to page 11 cents per kWh electricty.

 

Today, gas is 2.31/gal at the 7/11 where I would normally get gas.  My effective electricity rate last month was .088/kWh.  That would give me an MPGe factor of 26.25 (not as good as the standard 33.7 factor).  But this is more accurate in determining how much I'm saving over my old Sonata.  This is all assuming I don't drop into ICE mode at all.

 

How do you all keep track of your MPGe with and/or without ICE miles included?

 

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MPGe, just like mpg, has nothing whatever to do with the price of gasoline or electricity. 

It is based on the energy contained in a gallon of gasoline.

 

1. Divide the kWh used for a trip by 33.7 and that is the equivalent gallons of gasoline.

2. Add that to the number of actual gallons of gasoline used to get the equivalent gallons used.

3. Divide the miles covered for the trip by the answer in step 2 to get the MPGe for the trip.

 

The answer is the same no matter what you pay for gasoline or electricity.

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Mainly:

 

I use MPG when driving using the engine for any amount of miles, as it gives me a net MPG number for the entire trip dividing it by the gallons burned.  If I charge here and there on the way, well then that just improves my MPG number for the trip by adding in "free" miles.

 

I use MPGe when driving EV only trips, as MPG would show 999.9 all the time and mean nothing.  MPGe will give me numbers in the range of 135 MPGe in the winter to 200+ MPGe in the summer.  The higher the number, the better I'm driving for the conditions and the longer the car will go.  Its a gage of how well you did.  Electric is free as everywhere I charge is cost free, so its just an indicator for me for my trips.  Yesterday I drove 6 EV trips ranging from 3 to 20 miles for a total of 72 miles all electric and MPGe ranged from 153 on the highway at 51mph to 199 on country roads at 38mph.

 

-=>Raja.

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How do you all keep track of your MPGe with and/or without ICE miles included?

 

I don't. I can't even see the rise in the electricity bill, lost in the normal variation of household use. So I only care about gasoline used, and around town that is mostly none. When used as a normal car on road trips, the highway mileage is excellent, and better than anything I've owned before, and that is good enough until someone drops a European sized turbo diesel into something the size of a Focus or Fiesta, and then I'll buy that for road trips to get 60 mpg. And use the Energi for an around town EV.

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I use the spreadsheet I worked up and posted in this fuel mileage forum.

 

The answer is the same no matter what you pay for gasoline or electricity.

While this is true, this number is just as meaningless as mpge for someone who is concerned about things like total cost of ownership when cross shopping with other vehicles and break points where low gas prices may make driving on gas cheaper than driving on expensive electricity.

 

Or "how much saved vs his sonata."

 

For example, a slightly different calc, closer to the OP than yours, is needed for me to know that buying gas is cheaper than ever paying $2 to use some of the pay per hour or use public chargers around here.

Edited by openair
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I don't. I can't even see the rise in the electricity bill, lost in the normal variation of household use. So I only care about gasoline used, and around town that is mostly none. When used as a normal car on road trips, the highway mileage is excellent, and better than anything I've owned before, and that is good enough until someone drops a European sized turbo diesel into something the size of a Focus or Fiesta, and then I'll buy that for road trips to get 60 mpg. And use the Energi for an around town EV.

Isn't the VW Golf about the size of the Focus? That has a turbo diesel.

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