We have the full report on the new, very expensive, very light battery from Porsche. Details inside.

Porsche plans to market a new lithium-ion starter battery for three different 2010 model year cars.  The battery weighs under six kilograms, roughly ten kilos lighter than a normal lead battery.

Users of the 18Ah battery should notice no difference in performance when compared to the 60Ah Lead battery.  The reason for this is that lead battery users normally get the benefit of just 30% of the battery at any given time, versus the 100% available power of the Li-ion version.

Purchasers of the 911 GT3, 911 GT 3 RS, and the Boxster Spyder will be able to get the lightweight battery as an option.  German pricing for the battery is an astonishingly high €1,904, including VAT.

As if that is not bad enough, previous purchasers of those three models can retrofit the battery for €2,499, beginning in February.

Gallery: Porsche Announces New Lightweight Lithium-Ion Starter Battery Option