Friday, October 23, 2009

What's up? Not our range.

Range. After cost, it is perhaps the most important feature of an EV. The range you can drive between recharging will determine if you can even consider buying an electric car. One of the problems with range is it's not constant and there are many variables that can affect it. The MINI-E trial participants on the East Coast like myself are beginning to realize just how fickle range can be.

The temperature is dropping in the NY/NJ metro area and unfortunately so is our range. During the summer when many of us were using the air conditioning in our cars we noticed a small decline in the vehicles range, maybe 2-3%, but it was so small none of us really complained and many didn't even notice at all. That's not the case now. One of the participants (#486) had to be towed home recently. After 87.8 miles, he could go no further. He was driving the same route to and from work that he did all summer with his "E", why now couldn't the car make it? The car couldn't make it because it was in the 30s most of the day here in NJ and his lithium-ion batteries were freezing their kilowatts off. Another (#304) realizes he'll be driving the car much less during the winter months just to make sure he doesn't need to be towed. I think most of us knew the cold weather would have an effect on our range, but just how much was the question. The fact that the weather dropped so quickly also made it more surprising to see how much less we could go on a single charge. I've done a lot of research on EVs so I knew going into this that the winter months might be challenging, but even I was caught off guard by how quickly my range dropped. As I've posted a few days ago, I had a second wall charger installed at my business so I'll be fine. I can charge up any time I need to at work or home, but I'm the exception here as most of the others do not have that luxury while they are working. The reduced range has some of the participants worried that they may not be able to continue to use the car to commute to work and one person even told me that although they love the car, if they can't use it to drive to work they might as well give it back.

When I signed up for this I expected there to be problems. I new this was new technology and that MINI themselves really didn't know what to expect. I decided to do this to help advance the technology with the hopes of actually being able to buy an EV sometime in the near future. I had no idea how much fun the car would be to drive, that's been a pleasant suprise. I'm sure MINI knew there would be problems like this on the East coast. That's why they put 200 or so of us on the road here in the Northeast, to see how the batteries would fare in cold weather climates. If they are to eventually sell EVs, they can't just sell them in warm climates. The California participants are still driving around without any range issues, why would they, it's always freaking nice in Southern CA! Back here on the East though, some of us are getting worried. Perhaps MINI should have talked to the participants a little more about the potential issues before they issued the cars, just so everyone knew what to expect. While I knew there would be range issues in the cold, it seems that some of the others didn't and are really surprised and concerned now. I think an email to the East Coast participants a few weeks ago as a warning before the temperatures dropped would have been appropriate.

The Ugly Truth:
I have been keeping data on every trip I take since I got the car and I can see just when my range started dropping and just how much so. Up until October I had been averaging about 105 miles per charge. During that time I had single-charge trips of 120 & 123 miles and frequently drove over 110 miles. Since the beginning of October, I'm averaging 88 miles per charge, and only once hit 100 miles. On the day I did 100 miles, I drove the last 12 miles after my range indicator hit 0%. I thought for sure I'd be calling a tow truck myself, but luckily I made it home in reduced-power mode. On the colder days (those under 40 degrees) I'm only getting about 80 miles of driving range. That's almost a 25% reduction! What's going to happen when we get down under 20 degrees? I'm starting to wonder if the car will even work. Well, I'm in it for the long haul, regardless of how the cold punishes the batteries. I hope that whatever we go through this winter helps pave the way for better battery temperature management in future EVs. I'm confident I'll be able to make it back and forth to work now that I have a second charger at my disposal, and as I've said before, anyone in need of some juice can charge up whenever they need to at my restaurant, Nauna's Bella Casa, 148 Valley Road, Montclair, NJ.


  1. Hi Tom,

    I've been following the East Coast range issues on various blogs and hope that BMW will take all the info you folks are providing and come up with a solution for the actual production vehicle.


  2. Hey Todd. Yeah, that's the hope. I suppose there's going to be an effect from the cold weather no matter what they do, but limiting it should be the goal. I do hope they get useful info from us, that's really why I'm participating in the program.

  3. Is the range loss primarily caused by the use of the heater as other blogs have written about or does the cold have a direct effect on the batteries?

  4. Heater use does have an effect, but the cold weather is much more of the problem. When the battery temp gets below 70 degrees the range shrinks significantly. The batteries are dense so they do take a long time for the temp to get down that low even when it's much colder outside. Sitting overnight or outside all day will do it though. I think some of the others may assume it's the heater use, but I have done tests where I've driven with no heater use at all (froze my butt off)and the range had almost the same drop. Conversely, I have tested the heaters draw by leaving the car parked for 2 hours and run the heater to see how much of the battery it wold use. See my September 21st post about this.