Wednesday, August 29, 2012

Mitsubishi i-MiEV Window Sticker

Is an Electric Vehicle for everyone?

Definitely not. 

Who should consider an Electric Vehicle (EV)?  That depends on your motivations. 

If a person is looking to make a purely environmental statement, then the argument for an EV becomes simpler. 

If a person is looking at an EV for financial motivations, then looking at the numbers is a good place to start.  Let's start with some numbers from the window sticker.  The Fuel Economy is 112 MPGe (Miles Per Gallon equivalent).  The breakdown of the 112 MPGe is 126 miles rated for city driving and 99 miles rated for highway driving.  It is worth mentioning that the estimated range on a full charge is 62 miles (and that value also appears on the window sticker), so even though there is a 112 MPGe fuel economy rating, the actual range is still limited by the size of the battery.  It can be thought of as only having a half-gallon tank.  The vehicle is rated at consuming 30kW hours of power  per 100 miles.  And since the battery has a 16kW hour capacity, the "half-gallon" tank analogy should make more sense.  A few more numbers from the sticker...

You save $9,850 in fuel costs over 5 years compared to the average new vehicles.
Annual fuel cost $550.
The average new vehicle gets 22 MPG and costs $12,660 to fuel over 5 years.  Cost estimates are based on 15,000 miles per year at $0.12 per kW hour.

And now the breakdown of those numbers in terms of who would be an ideal candidate as an EV owner.  (This equation will change for cars with different driving ranges.  But since the i-MiEV is the car that is the focus of this blog, we'll stick with this one.)  Given that the car will travel 62 miles on a full charge, let's use that limitation as the basis for this optimal scenario.  To get the most financial value a person would want to drive as close as comfortably possible to the upper limit of the driving range.  And to say the "most financial value" is to say when it would make sense to drive an EV instead of an Internal Combustion Engine (ICE) vehicle.  It is not endorsing racking up extra miles without purpose just to add miles to the car.  So the ideal owner would have about a 25 mile commute to work (or school) and home each way.  That would be a 50 mile round-trip distance and would still leave a few extra miles for errands along the way or possibly driving somewhere nearby for lunch.  Those 50 miles a day (250 miles a week) over 50 working weeks a year (2 weeks of vacation is typically a minimum) computes to 12,500 miles a year.  That number is still 1250 miles shy of the 15,000 miles per year number used to compute the $9,850 savings over 5 years.  But the 1250 miles equates to an average of 50 miles for 50 weeks.  So maybe the ideal owner works one day during the weekend also, or finds a way to drive 50 miles during the weekend running errands.  But given that the battery would be down to a 12 mile range or less at the end of the day, it would need to spend 15-20 hours recharging if using 110V household current.  (The 15-20 hour range is just a wild approximation using Mitsubishi's 22 hour value to recharge a fully discharged battery.)  [My initial experience with recharging has been about 1 hour of charging yields 4 miles of driving range.  Using my unproven calculation, 13 hours on the charger would restore 52 miles of driving range.  Given that a 50 mile commute may take 1 hour, and add 8 hours for the work day and 1 hour for lunch, the car would be out of the garage for 11 hours.]  So one work-around would be to have a 220V (Level 2) charger available to recharge the battery in about 6 hours.  Ideally, that would be available at work (even better if it were paid for by the company) since the car sits for 8-9 hours during the work day.  If the owner has to invest in a Level 2 charger for the house, the approximately $3000 installation cost will eat away at the overall savings. 

So what would the new ideal daily driving range be that would allow time for changing at home using a 110V (Level 1) charger?  How about a 40 mile round-trip commute.  That's 20 miles each way.  A 20 mile commute may take about 30 minutes, so that's one hour of driving time per day.  Add 8 hours for the work day plus a generous one hour lunch, and the vehicle is out of the garage for 10 hours a day.  That leaves 14 hours to recharge.  The ideal above departs from the purely "most financial value" formula and tempers it with a bit of relief from not only range anxiety, but also charge time anxiety. 

My own scenario is quite different.  My drive to work is less than 2.25 miles each way.  An entire week worth of driving will only generate 22.5 miles.  If I only drove to and from work, the car could be recharged once every two weeks.  From that viewpoint alone it may not make sense for me to own an EV.  The break-even point versus what I would spend in gas in a car I already own would be decades.  That is where the other motivations play into the equation.  From a psychological standpoint, they could be called rationalizations.  Part of me is frustrated by the comments from anti-EV critics who state the shortcomings of an EV and then make the broad statement that they are unfit for any consumer.  Although I've yet to see anyone present an argument for the one vehicle that serves every purpose a consumer could need to fill.  It would be similar to pointing out that a motorcycle is limited in the number of passengers and cargo it can carry.  Still they are very popular.  If you look at a performance car, the fuel economy or the cost becomes an easy target.  You get the point.  Back to the motivations and rationalizations.  The frustrated part of me is in favor of EV's and I'm casting my vote of support not by words, but by actions.  Buying a product I support is commercialization the way it was meant to be.  It is also gratifying to pass a gas station and know that even if my other cars are subject to the changing market demands that cause the price of gas to fluctuate, the i-MiEV will not have to worry how much the next fill-up will cost.  Additionally, something that car enthusiasts will tell people is that driving a car too short a distance can be bad for it.  Especially repeatedly driving it short distances.  The negatives are caused when the engine does not heat up to proper operating temperature.  Some problems are caused when water condensation is not heated away.  This can lead to water allowed to collect in the exhaust system which can lead to corrosion.  An EV doesn't share this issue, so by commuting with an EV, I am extending the life of my other vehicles.  Depreciation is bound to happen to most cars.  But the ones driven less (or more importantly, driven properly) can retain more value longer.


  1. This is certainly an informative post! I have learned enough from here, getting some ideas for cheap window stickers.