Porsche is also introducing another new option in 2010 for the GT3 RS, a lithium-ion battery. Delivered with the car and, when replacing the conventional lead-acid battery, it reduces the weight by more than 10 kg or 22 lb and is mainly intended for the track.
Some more stuff about the Porsche lithium-ion battery, which replaces a conventional battery:
Specific characteristic:
A lightweight lithium-ion battery is optionally available for the Boxster Spyder, the 911 GT3 RS and the 911 GT3. Its shape and function are comparable to those of a conventional lead battery. However, the lithium-ion battery offers a weight saving of more than 10 kg in comparison with the conventional vehicle battery used as standard in the 911 GT3 models.
Compared to the conventional battery, the lithium-ion battery has the following advantages:
• Lower height by approx. 70 mm (over 35%)
• Almost 100% usable battery capacity
• Uniformly high power output, regardless of the charge state
• Improved charge take-up and a greater number of charge/discharge cycles
• Lower self-discharge and longer shelf-life
The lithium-ion vehicle battery will be included with the vehicle. Due to its similarity with conventional vehicle batteries (housing shape, fastening system and electrical connections), it can be quickly installed to replace the standard lead battery, e.g. for use on race circuits. The compact construction is outstanding, featuring a translucent upper housing cover with uniform arches, as well as high-grade battery terminals made from brass alloy. The housing arches and their semi-transparent design show the position and clear arrangement of the 4 lithium-ion cells.
Due to its design, the power output of the lightweight battery is limited below 0°C. The inclusion of the lithium-ion battery enables both the use of a lightweight vehicle battery for enhanced performance, as well as high day-to-day usability with sufficient starting power well below the freezing point using the lead battery supplied with the vehicle as standard.
Porsche Technology Glossary - Lithium Ion battery