Maintenance-Free Battery

WARNING: This page is about a different car, the 2010 Porsche Cayenne, 2009 Porsche Cayenne, and 2008 Porsche Cayenne. However, it is still accessible from the selected car via links, so may be relevant.

Information

The maintenance-free battery has an inspection glass.
The charge state and acid level of the battery can be checked through the inspection glass -B- .
If a battery is more than 5 years old and the indicator of the inspection glass is colourless, replace the battery.
If the battery has been charged, air bubbles can form under the inspection glass. Before carrying out a visual inspection, tap carefully on the inspection glass with something like the handle of a screwdriver.

Fig 1: Identifying Battery
Courtesy of PORSCHE CARS NORTH AMERICA, INC.

Three different colour indications are possible:

Fig 2: Identifying Battery

Courtesy of PORSCHE CARS NORTH AMERICA, INC.

Colour indication	Charge state
Green	The battery charge is satisfactory. Battery will start reliably.
Dark grey	The battery has no charge or the charge is too low. Recharge battery.
Transparent/clear	Acid level has become critical. Replace battery.