Anyone who regularly drives I-287 anywhere between Morristown, NJ and Rockland County, NY knows that it’s a race-track. It’s a relatively new highway, with wide lanes and shoulders, and for the NYC area is relatively light on traffic – so 75mph is pretty much the average speed.
When I first started driving MINI E #217 I backed off the accelerator a bit because of “range anxiety” (pulling into work with 49% juice makes for an exciting commute home).
However, now that I’ve established a benchmark of at least 110 miles with reasonable driving (~65-70mph) I have been starting to experiment.
A few days ago I ramped it up to between 65-75mph, and while I did see a few percentage points fall on the range, it wasn’t bad.
Yesterday, driving home, I decided to just keep up with traffic and see where that got me. For a :15minute period, i had it between 75-80mph, and I observed the chargeometer falling more or less as I would’ve expected. But then the bottom fell out – in a 2 minute period, I went from 40% down to 22%.
I pulled in the right lane and immediately fell back down to 60-65mph, and made it home with about 5% left (my usual is 10-15%).
From what I can tell, at the higher speeds the batteries really heat up (the meter shot up from 81 at the start to 99), and when they get hot, the charge fades quickly. It’s interesting to note though that if I can keep it to the mid-70s or lower, it doesn’t dissipate as fast.
I’m guessing the way to avoid this is, as the documents suggest, varying my speed in order to reduce the heat build-up. I guess that’s also why they took the cruise control out!