Although New York City mayor Michael Bloomberg has decreed that all cabs in the city must be propelled by at least a hybrid powertrain by 2012, moving to full battery propulsion looks like it's going to have to wait a bit longer. The Ford Escape Hybrids that have been in service for the past two years have been working great, but a test of battery powered Chrysler PT Cruiser was not so successful.
The PT converted to lithium battery power by Hybrid Technologies and tested in service as a cab for several months this year was never able to achieve the average distance for a cab of 100 miles per shift and never lasted a full ten-hour shift. The best it got was ninety miles one time and usually packed it in after only forty miles. It also didn't perform well in cold temperatures. The Taxi and Limousine Commission returned the car to Hybrid Technologies in June and will continue looking for other vehicles to test.
[Source: AM New York, thanks to Darryl for the tip]