Check maintenance-free battery

Fig 1: Vent hose A + connections and inspection glass B

Courtesy of PORSCHE OF NORTH AMERICA, INC.

NOTE:

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- . See Fig 2.
If a battery is more than 5 years old and the indicator of the inspection glass is colorless, 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 2: Maintenance-free battery

Courtesy of PORSCHE OF NORTH AMERICA, INC.

Three different color indications are possible:

color indication	Charge state
Green	The battery is charged sufficiently.
Black	The battery is not charged or the charge is too low.
colorless or yellow	Critical acid level.=> Replace battery.