One positive aspect of having a small battery is that it recharges quickly. The i3 can charge at up to 7.4 kilowatts, and I've observed it charging at my house at a rate of roughly 6.9 kW. Even when fully discharged to the 6-percent level at which the range extender turns on, it will recharge fully in about three and a half hours.
It charged to 90 percent in less than 3 hours, but that last 10 percent takes nearly 40 minutes as the charge rate tapers off to prevent overcharge in any of the cells. This is common in electric cars; I noted the same rate drop on both my BMW ActiveE and the MINI E that preceded it.
2014 BMW i3 REx range-extended electric car owned by Tom Moloughney - interior with four doors openEnlarge Photo
So far, the driving experience has lived up to my expectations. The BMW i3 s definitely much quicker than my ActiveE was, and the handling seems very good.
I drove it for about an hour at highway speeds in pelting rains last night, and it felt very well planted on the pavement--and never seemed to lose any grip.
I suspect the i3's tall, narrow tires will perform very well in wet and snowy conditions, but I have yet to really push them on dry pavement. I plan to do just that, soon!
Importantly, I had the opportunity to give the range extender its first workout.
I took my new i3 out on New Jersey's Interstate 80, and drove it west, almost from the George Washington Bridge (connecting to New York City) to the Delaware Water Gap on the other side of the state. I stayed almost entirely at highway speeds--from 65 mph to 80 mph--and most of the time it was raining.
2014 BMW i3 electric cars waiting at East Coast shipping port for distribution, May 2014Enlarge Photo
On that trip, the range extender came on after 69 miles--and I didn't even hear it when it did. I actually got worried that it wasn't working, because I hadn't heard it come on, but after a few minutes I realized the bar graph that showed the battery's state of charge had stopped falling. That meant the REx range extender must be holding the battery charge at a steady state.
I drove for about 35 miles with the REx running before I left the highway to test the BMW i3 on secondary roads. I carried my speed from 65 mph to 80 mph, and the car never flinched. Running on the range extender, it felt about 85 percent as powerful as it did in full electric mode--and, crucially, it was easily capable of accelerating and passing even at those speeds.
Once the REx had been on for a few minutes, I started to hear it as it revved up to a higher output. It seems there may be three distinct power levels, and after driving at high speeds for a while, it kicked into its higher speed to generate more electricity. You could then hear it running from inside the cabin--but with the radio on, it is barely noticeable and really only sounds like a slight background hum.