As automobile electrical and charging systems have become more complex, the battery has had some difficulty following suit. The standard automotive lead acid battery has remained relatively unchanged since its inception.
Today’s automotive electrical systems are becoming too demanding for anything other than a modern AGM (Absorbed Glass Matt) battery. 2005 and later Porsches, such as the 9PA (Cayenne), the sports cars i.e. 987 (Boxster and Cayman) and 997 (911) and now (especially) the new 970 (Panamera) operate using CAN (Controller Area Network) type bus systems that allow advanced communications between and within the many systems in the vehicle.
The CAN-bus system is intended to share information and operational responsibility between controllers and control units that can be physically located in different areas of the car. With all of this in mind, we often forget about the stringent demands the electrical charging system and battery are up against. The automotive battery is simply an electrical storage facility. Once the engine starts, the alternator supplies the electrical energy to operate the vehicle and replenish the battery’s energy lost during the starting sequence, or that used by other systems such as the alarm, lights etc., when the car was not operating. Basically, the alternator acts as the gatekeeper to the vehicles charging system.
Disconnecting the battery may sound like a harmless act, but doing so will erase all the important data the car needs to run properly and efficiently, including fuel injection adaptations and ignition system misfire adaptations. These adaptations are what your computer and engine management system have learned in an effort to run properly at its age and in its environment. Erasing these adaptations may lead to engine damage if certain conditions exist.
Remember to keep a battery trickle charger connected to your Porsche if it is in storage or not driven regularly. Next month — We will talk about what to do and, more importantly, what not to do if your battery is low or completely dead.
Tony Callas & Tom Prine