Friday, August 31, 2012

2012 Mitsubishi i-MiEV Range Change

How Far Can You Go?

Unfortunately the last couple charges in my Mitsubishi i-MiEV have had disappointing results in the actual number of miles traveled versus the estimated range after charging was finished.  Here are the numbers.  8/25: Started with 15 bars and finished with 2 bars.  (For the uninitiated, there are 16 bars that reflect the amount of energy available in the battery.  The number of bars showing generally decreases while driving, and is increased by charging.)  The estimated range was 63 miles at the start and 9 at the end for a difference of 54 miles.  Actual miles driven were 45.  9 miles short of the estimated range!  8/27: Started with 11 bars and ended with 0 bars.  53 mile estimated range at start and only a 2 mile estimated range by the time I returned home.  The change in range was 51 miles, but the actual miles driven were only 44.  7 miles short of the range!

The "bars" showing the battery charge remaining is on the left.
The estimated range is shown on the right.

Why is that a big deal?

If a person was only driving around town and never far from home, then it wouldn't be too big of a deal to miss the estimated range.  But I, and I'm guessing there are others also, would like to consider taking their i-MiEV on the road (or would consider buying one if they were confident in how far it could go).  If I pick a destination 50 miles away from home that has a Level 2 charger, and start with a fully charged battery [should have 62 mile range even when using A/C or heat], then I want to be fairly certain I can get there without coasting on electrons the last couple hundred feet.  With just a Level 2 charger at the other end of the drive, I'm already committing to a possible 6 hour stay before returning home.  From Rockford, IL that means I could consider Woodfield Mall in Schaumburg (home of IKEA, Joe's Crab Shack, and the Level 2 charger outside Whole Foods).  Unfortunately, IKEA and Joe's Crab Shack are located on the periphery of the Woodfield Mall complex and pretty much opposite where Whole Foods is located.  To just have to walk the extra distance isn't the issue as much as how much of a hassle it would be to actually buy anything of any bulk or weight and try to figure out how to get it back to the car which is committed to the charger for an extended period.  A bit of a tangent there, but relevant in terms of comparison as to how things are done with ICE (Internal Combustion Engine).  If driving an ICE vehicle, one could easily drive from parking lot to parking lot, which is what I have typically done in the past.

Individual results may vary

I am an advocate of Electric Vehicles (EVs).  If I didn't think they were a worthwhile endeavor, I wouldn't have purchased one.  So am I being critical when I discuss not getting the same driving distance as the estimated range?  No, I am being honest.  There are plenty of other owners with their own experiences.  Many of them share their experiences on  My hope is that I learn, and share what I learn, in regards to how to get the most effective range out of an EV.  An informed and educated public will be able to better decide for themselves what will compliment their lifestyle.

One theory I eluded to earlier was driving in the last quarter of bars (quarter "tank" if thinking in terms of gas) will result in a quicker loss of range than driving during any other part of the capacity band.  My last two driving experiences between charges have resulted in the car entering the last quarter "tank".  The car only has 157 miles total on it now.  The next few times I charge, I will try to drive while using the upper half to upper 3/4 of the capacity range.  It would be better to learn early how to optimize battery usage than to find out after months of travel.

1 comment:

  1. YVMV: Your Voltage May Vary

    The i-MiEV has a fairly linear battery response and a good estimation of range throughout it's operating voltage and temperature range. This is especially true when compared to the LEAF's
    "guess-o-meter". When one is planning a trip which involves long distances, large gains of elevation or travel in extreme weather then one must take into account all the energy required for the trip.

    The i-MiEV can travel as short as 30 miles at it's maximum speed of 81 MPH. It would be even less with the heater at full blast, the stereo cranked, one's tablet computer charging at full rate while navigating and streaming video over a cellular data connection.

    Alternately, in mild weather the i-MiEV can creep along using little more power than a pair of tandem cyclists (<100Wh) and travel for over 100 miles.

    If you wish to lengthen the lifespan of your battery, consider operating between 20 and 80 percent of full charge (about 2 to 13 bars). Only charge to 100 percent (16 bars) if you know you're going to need that energy. Lithium batteries will degrade more rapidly at extreme voltages, both high and low.