Thought I'd share a neat trick I've developed, but first some background...
My wife's i-MiEV is becoming 'range challenged'. This i-MiEV (named Moto
) which we bought used was probably abused as a child. With under 45K miles on the odometer, Canion shows the battery at 32Ah and with 'normal' driving its range is down to ~45 miles. This contrasts to my other i-MiEV (named Mitti
) which, despite showing 37Ah on Canion, still ekes out at least 60 miles if I need it. Remember, we sold our third i-MiEV (Mitsi
) a few year back. But I digress...
I have an old GPS mounted on each of my i-MiEVs for the express purpose of using its instrument panel to easily display the Distance To Go (DTG) to a programmed destination. Here are some older photos:
I use this DTG number to bounce off the i-MiEVs RR (Range Remaining) to make sure I stay out of trouble. DTG is the upper-right number in the above photo.
As long as RR>
DTG, I'm ok.
Sooo, what's the story? A couple of days ago, since my i-MiEV still had the bike rack with bikes on it, I had borrowed my wife's i-MiEV for a quick trip to a gourmet food take-out that a friend recently started (in the middle of this pandemic!), but I took a circuitous route to take care of some business and didn't fully charge before leaving. Anyway, there I was down in San Jose with 8 bars and RR-32 - 'perfectly normal' you might say, as that is exactly what my other i-MiEV would read. Hey, the trip home is only 16 miles, so what's the problem?
The problem is that the outbound trip had an altitude drop of 600ft and I hypermiled all the way on a 45mph expressway and I had started with maybe 12 bars and covered at least 20 miles going there. The trip back was freeway for 13 of those 16 miles...
I could easily have stopped at a nearby EVgo DCFC for a few minutes, but, nooo, I was determined to go straight home (I was hungry), knowing full-well that the RR=32 was, in reality, really closer to the 16 miles I had left to cover (because of the aforementioned hypermiling and altitude drop), because I was now going on a freeway (where even 55mph in the right lane is iffy) and had the 600ft climb to get back home.
Remember, the RR calculation is a moving average based on how the car was driven for the preceding 15 miles (24km).
OK, ok, I'll shut up - what's the trick?
Simple: I put my home destination into the GPS and have a nice clean DTG (Distance To Go) number displayed on the screen. 16 miles exactly. Remember, the Range Remaining is displaying an artificially-inflated 32 miles.
Trick: If I could maintain a 2:1 ratio of RR:DTG for the entire trip then I'd be ok.
Sure enough, after I hopped onto the freeway the RR started dropping precipitously and the ratio soon dropped below my 2:1 comfort level... long story short, arrived home with one bar blinking... whew!
After over 150,000 miles combined of i-MiEV driving neither my wife nor I have ever seen 'turtle'.
Postscript: along the way I had a number of DCFC stations I could have gone to, so there was really no drama except for the last two miles climbing home.
Thanks for listening.