Porsche lightweight lithium-ion 12-Volt starter batteryEnlarge Photo
Lithium-ion batteries are part of the path to the Promised Land of electric vehicles. The all-electric 2009 Tesla Roadster was the first sports car to run on lithium cells, and the 2010 Mercedes-Benz S400 was the first hybrid electric vehicle to feature them.
Now Porsche has joined in, offering a lithium-ion battery as an option on its highest performance models. But it's not what you might think; their wheels are still turned solely by the company's lengendary flat-six engines, lately through direct-shift gearboxes. It has nothing to do with that all-electric 911 concept, either.
Instead, the lithium-ion battery is simply a lighter-weight substitute for the Porsche's standard lead-acid 12-Volt starter battery.
2011 Porsche Boxster Spyder Los Angeles 2009Enlarge Photo
Its 13-pound weight cuts a full 22 pounds off the standard item, lightening the car just as carbon-fiber body panels or deleting comfort items like air-conditioning does. Porsche's 2011 Boxster Spyder, debuted last week at the Los Angeles Auto Show, does without A/C or radio, and its doors are aluminum rather than steel.
Compared to a lead-acid battery, the lithium-ion pack recharges faster and lasts longer, since it can be charged and discharged far more often. Porsche actually delivers a lead-acid battery along with the lithium option, though, since the latter's power falls off at temperatures below freezing.
The new lithium battery has the same form factor and mounting points as a standard 12-Volt battery, but in addition to being lighter, it's roughly 3 inches lower.
Continuing the long tradition of pricey Porsche options, it will cost $1,700 when it goes on sale next month as optional equipment in the 2010 Porsche 911 GT3 and GT3 RS as well as the Boxster Spyder.