Miles per e-gallon

Hi Everybody, I know we don't like to use the figure MPeG(miles per e-gallon) but its useful for general purposes to compare against other vehicles and to be consistent on where the power calculations are coming from.. For example from the batteries or from the wall.. An e-gallon is the electrical equivalent of a gallon of gasoline or 34KWH.. And to be fair , it seems that the fuel source should be at the wall and thus include the efficiency of the charger too..

So here goes the question : what are the owners of the Nissan leafs getting for MPeG's ?.. the fuel sticker on the car says 99 i think.. I saw a set of calculations from a previous post where it was 123 MPeG ..

I figure it a little differently so that the average ICE person can appreciate the reference: I tell them that when you figure the current cost of gas and the cost of electricity, the equivalent cost of operation is roughly the same as if I got about 200 miles per gallon...

mikee322 said:

Hi Everybody, I know we don't like to use the figure MPeG(miles per e-gallon) but its useful for general purposes to compare against other vehicles and to be consistent on where the power calculations are coming from.. For example from the batteries or from the wall.. An e-gallon is the electrical equivalent of a gallon of gasoline or 34KWH.. And to be fair , it seems that the fuel source should be at the wall and thus include the efficiency of the charger too..

So here goes the question : what are the owners of the Nissan leafs getting for MPeG's ?.. the fuel sticker on the car says 99 i think.. I saw a set of calculations from a previous post where it was 123 MPeG ..

Click to expand...

mikee322 said:

An e-gallon is the electrical equivalent of a gallon of gasoline or 34KWH..

Click to expand...

Shouldn't that be 36.6 kWh/gal?

http://en.wikipedia.org/wiki/Gasoline#Energy_content_.28high_and_low_heating_value.29

I'm averaging around 5 miles/kWh on my commute, which is 180 miles/e-gallon.

EDIT: This is from the Leaf dash, I don't yet have a way of measuring it at the wall. Estimating charging efficiency at 80%, that's 144 miles/e-mile.

Using your 34 figure, my best has been about 137 mpge, which is about 4.0 mi/kWh at the wall. But my lifetime average is about 107.

The eGal problem is gasoline has to be converted to work by a heat engine while the electric motor has it's energy source in a ready to use form. If you use the BTU input to make that KWHr from a Rankine cycle then the ~200 mile/egal is multiplied by 0.4 or 80 MPG. This matches well with another metric to look at CO2 produced per vehicle mile where the reduction in CO2 from using BEV is compared to ICE. When the ICE gets to ~60 MPG (CAFE 2025) then the BEV and ICE are equivalent in CO2 impact.

I bought a LEAF because I wanted a simple car with few moving parts and an independent or self sufficient energy source. The CO2 and MPG and cost per mile are other interesting facts that cause trouble by pointing out the disparity in energy costs.

It's over 200 for me (5.9-6.3m/Kwh).

Since a gallon of gas is considered/defined as equivalent to about 32 (or 34, I forget) kWh by the EPA, our 24 kWh is only about 72% of a gallon.

So, do 72 miles on the LEAF's "little" 0.72-gallon "tank", and you get 100 mpge!

Stretch to 144 miles on flat, constant 35-mph driving (about 4 hours), and you are doing 200 mpge!

So, real miles per kWh (mpe, or "miles per edi") times 32 (or 34?) equals your mpge ("miles per gallon-equivalent").

Or, to really "appear" even better, use the phony Carwings miles per kWh (or Miles per Edi = mpe) and ... multiply by 32 (or 34) ... :lol:

I posted about this recently. I hope I can help figure out some numbers with you all.

With the three metrics I've outlined I get:

MPGe - Efficiency - 113
MPGe - Emissions - 79
MPGe - Economy - 112

Of course those totals are for my locale, gas was $3.999 just three weeks ago.

Once I get my second meter with PG&Es' E9B rate, adjusted for lower gasoline costs since I last blogged, I estimate my Leaf will get approx. 220MPGe economy

I love this stuff. Some great numbers in there...
The Beauti of e-gallons, is that it gives volt owners and future dual fuel user (vehicles) a easy way to figure out their combined Miles Per Gallon.. Instead of treating electric fuel as non existence as Ive seen in some of the Volt MPG Blogs..

Another advantage is to be able to compare Prices of a Gallon of Gasoline to a Gallon(equivalence) of electricity... I'm sure these Numbers will vary greatly,depending on your power company...

EX: I just looked at my May electric bill(Florida Power and Light) . It was a 194.29$ for 1676KW hours... And e-gallon according to EPA is 33.7KWH .. I use 34KWH just for simplicity... So how much is a block of 34KWH's? in my case 3.94$ .. If i remember , gas was around 4$ per gallon in May, Pretty close to the Price of a e-gallon(34KWH's)

Since the EPA has defined an electric "gallon" as just shy 34 kWh, the LEAF has about a 3/4 gallon-equivalent "tank", smaller than most motorcycles.

So, if I get 90 miles out of my 3/4 g-e "tank", , that's 120 mpge.

Or, as we might think of it, shy 4 mpe (miles per edi, or miles per kilowatt-hour, if you prefer).

garygid said:

Since a gallon of gas is considered/defined as equivalent to about 32 (or 34, I forget) kWh by the EPA, our 24 kWh is only about 72% of a gallon.

So, do 72 miles on the LEAF's "little" 0.72-gallon "tank", and you get 100 mpge!

Stretch to 144 miles on flat, constant 35-mph driving (about 4 hours), and you are doing 200 mpge!

So, real miles per kWh (mpe, or "miles per edi") times 32 (or 34?) equals your mpge ("miles per gallon-equivalent").

Or, to really "appear" even better, use the phony Carwings miles per kWh (or Miles per Edi = mpe) and ... multiply by 32 (or 34) ... :lol:

Click to expand...

Based on the numbers above, I average 5 miles/kWh (Leaf dash) or 170 mpe, the Carwings version would be a ridiculous 215 mpe.

170 mpge, not mpe

I'm with you Mogur, I don't feel that the way the EPA equates the MPG really conveys a meaningful economic equivalent that ICE drivers can relate to. Comparing the cost per mile to drive the LEAF, I too am seeing more like 200+ miles per gallon... As in 2.2 cents per mile! My electric bill for charging the LEAF last month for 1500 miles of driving was around $30!!!!! I'm seeing essentially double what I expected from the EPA numbers. And all these years I thought the EV enthusiasts were exaggerating because it sounded so preposterous, who would have thunk!
G

mogur said:

I figure it a little differently so that the average ICE person can appreciate the reference: I tell them that when you figure the current cost of gas and the cost of electricity, the equivalent cost of operation is roughly the same as if I got about 200 miles per gallon...

mikee322 said:

Hi Everybody, I know we don't like to use the figure MPeG(miles per e-gallon) but its useful for general purposes to compare against other vehicles and to be consistent on where the power calculations are coming from.. For example from the batteries or from the wall.. An e-gallon is the electrical equivalent of a gallon of gasoline or 34KWH.. And to be fair , it seems that the fuel source should be at the wall and thus include the efficiency of the charger too..

So here goes the question : what are the owners of the Nissan leafs getting for MPeG's ?.. the fuel sticker on the car says 99 i think.. I saw a set of calculations from a previous post where it was 123 MPeG ..

Click to expand...

Click to expand...