Automaker BYD is by far China's most aggressive when it comes to electric cars.

It launched its F3DM sedan, the world's first production plug-in hybrid, back in December 2008--sales have been poor--and has been testing its all-electric e6 crossover with both taxi fleets in Shenzhen, China, and the Housing Authority of Los Angeles.

Encouraging data

Now the results are in from a year's worth of the taxi tests, and BYD considers them encouraging.

Fifty of the five-seat e6 compact crossovers were used in regular taxi service by Pengcheng Electric Taxi Company. The quoted range for the e6 is more than 160 miles, with a top speed of 88 mph.

Those 50 cabs have now accumulated more than 1,730,000 miles, BYD says. That's an average of almost 35,000 miles per cab, with a few of the electric taxis covering as many as 63,000 miles over the year.

Frequent rapid charging

BYD e6 electric taxi in service in Shenzhen, China

BYD e6 electric taxi in service in Shenzhen, China

That's 175 to 315 miles per day (depending on how many idle days those high-mileage cabs incurred), meaning at least one recharge during the day's travels.

According to BYD, battery performance has stayed consistent and driving range has not declined, despite the repeated use of quick charging--which an MIT study indicates may harm some lithium-ion battery packs. Each quick charge took only 20 to 30 minutes, though it fills the pack only to about 80 percent of capacity.

"Drivers and passengers alike have been extremely satisfied with their ride experience,” said Stella Li, a senior vice president at the cab company (in a press release from BYD), despite both the hot summers in Shenzhen and a particularly cold winter.

Another 250 e6 taxis are to be delivered to the International University in Shenzhen by August.

More miles required

byd auto f3dm plug in hybrid 08

byd auto f3dm plug in hybrid 08

While this is undoubtedly encouraging, one year of use--or a handful of cars each covering 60,000 miles--is too little to prove the long-term reliability of the battery packs. The 2011 Chevy Volt's pack, for instance, is warranted for 8 years or 100,000 miles, as is the pack in the 2011 Nissan Leaf.

In its release, BYD also noted that the Housing Authority of Los Angeles has accumulated 14,500 miles on its fleet of 10 F3DM plug-in hybrid compact sedans, of which 10,500 were in all-electric mode. The fleet is thus averaging 88 miles per gallon.

BYD's modest Los Angeles test fleet is its latest effort in the U.S. market. It has missed a number of self-imposed deadlines for launching sales of its e6 in the U.S. The company now says it will recruit dealers for a late 2011 rollout.

Mixed reviews and Wikileaks

Few auto journalists to date have driven the BYD e6, though a Financial Times reporter gave it a mixed review, noting bland styling and slow acceleration (in Eco mode) but saying it delivered on the promise of basic electric transportation.

Earlier this year, BYD was caught up in the Wikileaks scandal, with leaked information accusing the company of copying other makers' products and intellectual property in its quest to create a global-scale Chinese auto company.

Whether that will happen is still very much up in the air. But at least BYD is now doing the kind of durability tests that most automakers--Nissan, Chevrolet, BMW, among others--have performed on their electric-car designs before releasing them for sale to the public.

And that, too, is encouraging.



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