The Future of the Automobile? Part 3 – Steady Driving?

This is the 3rd in a series discussing my experience driving the all-electric BMW ActiveE.


Last Tuesday the odometer hit 1,000 miles.BMW ActiveE

Last Wednesday the thermometer in Boston hit 96 degrees, a record for the day.

Last Wednesday evening the car would not start.

Coincidence? I still don’t know.

The dashboard message read: “Drivetrain malfunction; contact Roadside Assistance”. I left the car at my office overnight, hoping it would cool off and I could start it in the morning. That did not work and I had to have the car towed to the dealer.

I have just gotten it back – a week later. I still do not have a clear answer of what went wrong. BMW diagnosed the problem remotely and told the dealer’s service department what to do. Something about a cable replacement (which I did not see on the service report) and removal of the motor and battery to add grease that had prematurely dried up on the input shaft. No one claimed to have any idea if it was weather related – or if other people had reported a similar problem.


I will keep trying to get to the bottom of it.

Aside from that…….

(Actually, I really have been enjoying the car).

Range and Charging Redux

Last time I reported that the car had never shown a range of greater than 82 potential miles, which is well below what it is supposed to be able to achieve. I am pleased to report that I got the gauge up to 94 miles – the stated max range – albeit briefly, before it settled back down at 92 – 93 miles. I believe this increase to be due to a combination of mt learning how to better leverage the regenerative braking function and the warmer weather. (Before it got too warm, I guess). I have not yet had the opportunity (or courage) to set out for a destination 45 miles from home and really check out the range.

On a less positive note, last time I also reported a “miles per gallon equivalent” of more than 100 based upon the initial charging times I was seeing, using a standard 120V wall outlet. It looked like it would take 13+ hours for a full recharge, and draw about 18.7 kilowatt hours, which translates into $2.80 for a full charge. (I had not yet drained the battery more than 40{9e9e99e0aa33304967f3b3f95b41a9c8b857afbbbf6b3eae28bf86859e197ae9} when I first tested recharging time).

I then switched to using a 240V charging station – and the numbers look entirely different.

Below is a plot of power vs. time using the charging station to recharge the battery when it was 63{9e9e99e0aa33304967f3b3f95b41a9c8b857afbbbf6b3eae28bf86859e197ae9} depleted. (This chart was generated by my firm’s SiteSage® energy management system).


The car drew just under 20kWh during this period, which suggests – if charging is linear (which early data suggests may not be the case) – 35 kWh for a full charge, or $5.25 for a full 94 mile “tank” at our utility rates. That is still only 5.5 cents per mile, which is the equivalent of getting 72 miles per gallon at $4.00 per gallon (rounding up to the nearest dollar). Not bad, but not remotely what I was expecting – or what is needed to make electric cars an economically reasonable alternative.

I was planning to try 120V charging again to get a sense of whether this is a car issue or an issue with the charging station – but not having had the car for the past week took care of that idea. So, stay tuned for the next post.

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