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Discussion Starter #1 (Edited by Moderator)
Hi, I'm a recent convert, having just purchased a 2014 Premium with 67k. I'm really impressed and as a former automotive engineer and product planner, I applaud GM for their efforts.

Here's my question: The Trip Meter "A" has never been reset so it shows the full vehicle mileage 67k and 60.4 MPG. At the same time, my center stack energy display shows a "lifetime" reading of 32.7 MPG. (This has been trending up, when I first took delivery a week ago it was 30 MPG.)

Why would these two be different by a factor of two? How could the "Lifetime" reading be so low? Driving home from the Seattle dealer (250 miles), of course was mostly ICE but still I was getting 37 MPG. (Now that I'm home it's all electric and "250+")

Thanks in advance,
Craig
 

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If I had to guess, I would say Somone has used an OBDLink MX adaptor and a freely available app in the Google play store for Android devices called "my volt lifetime" to reset the lifetime counter.
 

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Discussion Starter #3
Thanks for the reply IceCoffee. Your theory makes sense. I can't imagine the internal calculations for the two numbers are different, let alone different enough for 2x variation in the displayed answer. Anyone else care to venture into this strange MPG result? I'm all ears!
 

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Those numbers should be the same, so as IceCoffee suggested, something has happened to the history in one of those records. However, I doubt the previous owner purposely reset it because at 32.7 mpg, whoever has been driving it since then has zero regard for efficiency, so I don't see why they would have reset it. Maybe a repair was necessary that replaced the module that tracks lifetime mpg in the center stack.
 

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I would recommend ignoring that silly "Lifetime MPG" number. It does not relate to your driving efficiency. Some people have long commutes or just like to drive and do not restrict themselves on taking road trips with their Volt. The Volt has an ICE and some folks are not skittish about using it.
 

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Discussion Starter #6
Thank you all for your replies. Most likely the selling dealer, a Subaru/Chevy dealer with quite a few Volts around, repaired something before sale that reset the number. I say that because the number is now up in the mid 33 MPG range and if it really reflected 67k miles my "new" 400 miles wouldn't have had such a large effect against a 67,000 mile average. At any rate, thanks to all!:cool:
 

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The Volt’s energy usage screen in the center console is, in effect, a "Trip C" counter. The Lifetime MPG display is capable of being reset by a trained technician for a new owner, or by the use of an available app.

My understanding is the Volt’s computer retains the vehicle "lifetime" data, so that any Lifetime MPG numbers reported via OnStar for your own vehicle to the various websites (mychevy.com, voltstats.net for registered owners) would be the vehicle’s lifetime MPG. If, indeed, your Volt’s center display MPG has been reset, then the center display’s Lifetime MPG will represent the time of your ownership, not the car’s Lifetime MPG.

FYI, math says the lifetime gas used (in gallons) is also the number of miles you need to drive on battery power only to increase the lifetime MPG by 1.0000. Your Trip A counter indicates this would require driving 1,120 miles on grid power with no gas used to increase the lifetime MPG from 60.4 to 61.4.

How many miles are you now driving to get the center display MPG to jump up by 1?

You seem to indicate it’s gone up by ~1+ in the time it’s taken you to drive your first ~400 miles in this car (including the ~250 gas miles from driving from Seattle). That suggests your energy usage screen’s Lifetime MPG number has been reset. It’s now increasing by 1.0000 each time you drive a given distance using only grid battery power and no gas. That distance is also the total gallons of gas you have used since the lifetime MPG was reset (~7 gallons on the initial trip home plus ?).

IOW, watch this counter to see how many ev miles you now need to drive to add 1.000 to the center display Lifetime MPG number... for example, let’s say, from the moment the counter changes to 33.8(000) MPG to the moment the counter changes to 34.8(000) MPG. If you use no gas at all during that driving, then the distance in miles driven to increase the MPG by 1.0000 is also the total gallons of gas used since the Lifetime MPG display was reset.

An MPG of 34.0000 after driving 500.0 total miles (that included 200+ gas miles), for example, indicates a total gas consumption of 14.7 gallons, and the MPG would increase by 1 for each 14.7 ev miles driven thereafter with no gas used...

Keep in mind that MPG (= total electric + gas miles/total gas used) is a meaningless number for a Volt whose driver can choose to use gas or to propel the car down the road without using any gas at all (only the 2011/2012 Volts have no Hold Mode). The MPG for a Gen 2 Volt’s daily 42 mile round trip commute (21 miles each way, window sticker rating of 42 mpg) can vary each day on the same route from 42 to 84 to 250+ MPG depending on the choice of the driver to use no Hold mode on the commute, use it for one direction only, or use it for the entire drive.
 

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Discussion Starter #8
Thanks for the in-depth answer, Wordptom. I think you're absolutely right. Your response, along with others, has convinced me the lifetime number was recently reset.

I reset my "Trip B" when I got home from Seattle and since then I've driven the car about 450 miles. That short mileage (vs the 67k total) has moved the lifetime number 3 MPG already. This could only be possible without the weight of the 67k miles in the average. I'm considering having it reset again to reflect my ownership rather than the false number it's currently showing. Thanks for your detailed answer!
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