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Discussion Starter #1
I am curious how I consistently get 42/45 miles per charge but yet average 58/66 MPGe according to voltstats.net data collection.
I have a 2014 and I know the EPA rating is 38 estimated miles per charge and 98 MPGe. Wouldn't the MPGe be directly related to actual miles driven on a full charge?

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What percentage of your total driving to date is EV versus gas? If you regularly drive beyond your EV range your lifetime MPGe will be much lower than ~ 98MPGe. For the Gen 1 Volt GM estimates 80% of daily driving can be completed using only the battery, for the Gen 2 Volt this estimate is 90%. For example, if you regularly drive 45% EV and 55% on gas your MPGe would be (.45 * 98MPGe) + (.55 * 38MPG) = 65MPGe. For the Gen 1 Volt, using GM's estimate of using EV mode for 80% of daily driving the theoretical blended MPGe would be 86MPGe. For the Gen 2 Volt @ 90% EV for daily driving, a higher 106MPGe for EV mode and a higher 42MPG when using gas, the theoretical blended MPGe would be 99.6MPGe.
 

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Discussion Starter #3 (Edited)
That is probably the issue. My normal commute is 75/80% EV but it seems that I need to do 150/250 mile out of town trip once or twice per month. Just kills my numbers!
Lifetime is showing 79.6% EV and 72.98 MPGe. Lifetime MPG is 179.06 as of today. 31k on the odometer with almost 25k total EV.

Edit: The car was purchased last February with 20k miles and a lifetime MPG of 234.

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When using battery, with an estimated EV MPGe of 82MPGe, when using gas with a gas MPG of 38MPG, for your stated 79.6% EV mode and 20.4% gas mode yields a combined electric and gas MPGe of 73 MPGe. It appears that GM did their homework, i.e for the Gen 1 Volt they knew that the typical driver would be be able to drive ~80% gas free (even accounting for regular out of town trips.)
 

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Discussion Starter #5
When using battery, with an estimated EV MPGe of 82MPGe, when using gas with a gas MPG of 38MPG, for your stated 79.6% EV mode and 20.4% gas mode yields a combined electric and gas MPGe of 73 MPGe. It appears that GM did their homework, i.e for the Gen 1 Volt they knew that the typical driver would be be able to drive ~80% gas free (other than for out of town trips.)
Thank you Sir! I appreciate it.

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Wouldn't the MPGe be directly related to actual miles driven on a full charge?QUOTE]

Sure, the MPGe is directly related to actual miles driven on a full charge, but you have to drive far enough to require recharging multiple times to use up one MPGe gallon. Your Volt’s electric fuel tank doesn’t hold much fuel.

The Wikipedia "Miles per gallon gasoline equivalent" article uses 33.7 kWh of wall-to-wheel electricity as the equivalent energy consumption unit for one gallon of gasoline.

For me, MPGe is far too large a number to have any meaningful application to the Volt. The usable power in the fully charged 2014 Volt battery, converted to MPGe measurements, has the same energy consumption amount contained in about 6.2 cups of gasoline. For the Gen 2, the battery hold the equivalent of about a half gallon. How precise can trip MPGe readings be when the full tank holds only a fraction of the fuel unit’s volume?

Your 2014 Volt’s gas tank holds 9.3 gallons of gas, your electric tank holds only 0.38 gallons of gas-equivalent. To drive the MPGe equivalent of 1 gallon of gas, you would need to drive on battery far enough to require three about full recharges. You would need to recharge a completely depleted battery ~24.5 times to put the gallon-equivalent of 9.3 gallons of gas into your electric fuel tank.

If you normally use up one gallon of gas in the time span needed to drive on battery far enough to fully deplete and recharge your battery three times, it’s easy to see why your lifetime MPGe might be in the midpoint between your MPGcs and your car’s MPGe ev rating.

Many of us do not often drive far enough in a day to fully deplete our battery, so have rarely driven our actual all-electric range using a full battery charge. If we don’t, we rarely confirm how accurately any given day’s full charge range estimate predicts the AER. Who among us has ever partially recharged the car multiple times to confirm we can actually meet or exceed the window sticker ratings of 94 (2012 Volt) or 98 (2015 Volt) or 106 (2016 Volt) "electric miles per 1 gallon gasoline equivalent?"
 
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