By Abe Ostrovsky with contribution from Peter Whealton
I leased an electric car nine months ago. A 2014 BMW I3 rex. The BMW advertising was clear. Eighty-seven miles per full charge plus 48 miles of additional range from the range extender, a built-in gas driven generator that recharges the battery while driving. The gas tank serving the generator is 1.5 gallons. The extender is meant for the occasional short additional miles to reach a charging station when a destination turns out to be just beyond the electric range or mishaps on the road mandate a detour.
My discussions with the sales person reinforced the claimed range and I was further reassured as I read that since BMW did not expect the range extender to be used regularly, it would automatically come on and cycle for 5 or 6 minutes every 2 months to keep it lubricated and ready.
The battery charger that is included with the car is classified as a level 1 and takes 20 hours for a full charge. BMW sells a level 2 charger (an extra $980 accessory which requires wall mounting to a 220 Volt, 30 Amp source – it cost me $250 to provide this power in my garage). This charger will charge a depleted battery in 3+ hours. The logical operating radius for the car is therefore 43.5 miles one way assuming there is no time to recharge the battery at the destination.
In my case, 43 miles was sufficient to reach most addresses in Los Altos Hills and San Jose was reachable depleting the battery one way. This covered most of my needs so I leased the car, bought a level 2 charger and had an electrician install it in my garage.
Soon I learned that the car was capable of delivering the 87 mile range only when driven carefully (no quick acceleration and no extensive brake usage) on flat streets (no San Francisco hills) in a mode that deactivated many features (no AC or heat or seat heaters) at a maximum speed of 56 miles per hour (no expressway driving). The actual range being driven normally (I am told I am an aggressive driver) on San Francisco hills and Bay Area expressways is around 50 miles, just a few miles more than half the advertised range.
Just so there is no misunderstanding, I think the I3 is a great city car. It is well featured, easy to drive, has nice pep, handles well, parks easily and transports 4 comfortably. As a city car in San Francisco, a city that is approximately 7 miles by 7 miles, it is terrific. But if normal usage requires more than 25 miles one way, the battery system is inadequate.
My investigations into battery technology indicate that advances in battery density (the amount of stored electricity available per pound of battery) is rapidly increasing. Chevrolet has recently announced the Chevy Bolt, a compact expected to deliver 200 miles of range on a fully charged battery which should be available by end of 2016. I expect that battery technology advances will allow a doubling of range for same size and weight batteries by 2017. At that point the lower price electrics will have sufficient battery power to compete with gasoline powered cars at competitive pricing.
Until then, I will continue to rent Zip cars when going further than the short rides to San Carlos airport, Walnut Creek or Lucas Valley.
