Volt MPG Request

If you haven't already, I'd also post your query on gm-volt.com.

 

Use this tool to confirm some EV estimates. See if you can figure out how many miles you will have remaining after exhausting the battery. Use 10.8 kWh for a 2013 model, NOT the 16kWh the tool defaults to.

www.jurassictest.ch/GR/

You should easily stay in EV mode on the 40 mile downhill morning commute. The 40 mile uphill commute without a fresh charge will kick in CS mode. Worst case you will use an entire gallon to go the 40 miles, but I'm guessing you will get as much as 15 miles of EV on the afternoon commute and then 25 miles of CS, at about 38 mpg, uphill, or 2/3 gallon. This is just a guess and you might do significantly better.

If you use:
2/3 gallon for 80 miles, thats about 120 mpg,
1/2 gallon would be 160 mpg.

If you can manage to find a place for charging during the day, it would be worthwhile. Consider locations that are walkable from your destination. I often plug in and walk as much as 10 minutes to destinations just to avoid using gasoline and getting some exercise.

 

The 2013 has the hold button to save EV charge, so you can optimize when using electric. Such has turning over to gas on the downhill highway stretch. Keeping it below 65, or better yet 60, then will surely beat the EPA 40mpg then.

 

Conservatively, I'd say to estimate one gallon a day. 500 feet over 40 miles isn't exactly what I would consider downhill, but you'll probably get there on electric and burn a gallon getting back.

I've driven a Volt for 2 years and more than 30,000 miles.

Should also add there are different schools of thought with regard to that one gallon over 80 miles, because it doesn't factor in the 10 some odd kwh's you'll also burn it is not accurate to describe your overall efficiency as 80 mpg. I'm too tired to do math right now but its about another 1/3 of a gallon of energy so I estimate efficiency equivalent around 60 mpge.

 

After you learn to optimize your driving, you will likely have about 10 miles of range left when you get to work if it is downhill. But that will bleed off pretty quick on the way back. I think the estimates of using 1 gallon are pretty solid.

 

A full charge of 13kwh is approx 1/3 gallon of gas (approx $1.43 at national avg of .11cent per kwh)
NOTE: the following isn't the exact way mpge is calculated which can be found here: Miles per gallon gasoline equivalent - Wikipedia, the free encyclopedia

If you get:

35 miles EV=.3 gallon
15 hwy miles gas at 40mpg=.375 gal
50 miles/.675=74mpg(e)

or
38 miles EV=.3 gal
12 hwy miles/40mpg=.3 gal
50 miles/.6 gal=83mpg(e)

40 miles EV=.3 gal
10 hwy/40mpg=.25 gal
50 mils/.55 gal=91mpg(e)

YMMV

 

maybe another approach to estimating a specific commuting scenario. use the tool but adjust the battery size to some number like 100kWh rather than 10.8kWh.

www.jurassictest.ch/GR/

get the total kWh consumption for the round trip commute.

subtract 10.8 for the standard full charge
for every additional 10.8 kWh consumed substitute 1 gallon of gasoline.

example :

80 miles, if tool says 18kWh needed.

18 - 10.8 = 7.2

7.2/10.8 = 0.67

0.67 x 1 gallon = .67 gallons of fuel.

 

look at fotomoto's math above for the first 50 miles, to keep the math easy I'll use his third example of 40 miles EV and 40 mpg thereafter (about what I would expect in your climate).

So for the first 50 miles you got 91 mpge
50 miles later you will have burned another 1.25 gallons, so 100 miles on 1.8 gallons (or equivalent) or 55.6 mpge
at 150 miles you're at 3.05 gallons or equivalent or about 49.2 mpge
at 200 miles you're at 4.3 gallons or equivalent or about 46.5 mpge
at 250 miles about 45.0 mpge
at 300 miles about 44.1 mpge
and so on approaching the lower limit of 40 mpge.

edit:
Knowing your personal use patterns is very important in deciding if a plug-in suits you, the more you can stay in the electric range the more benefit you will receive, there is no one best car for every possible driver. The Pip for instance is a good choice if you consistently drive longer distances where the more efficient gas engine becomes a bigger factor.