Remove battery

Switch ignition off and remove ignition key.
Open turn-lock fasteners -A- .

Fig 1: Opening Turn-Lock Fasteners On Battery Cover
Courtesy of PORSCHE OF NORTH AMERICA, INC.
Remove battery cover.
First disconnect the ground strap of the battery on the negative battery terminal. Unscrew hexagon nut and remove terminal.
Undo hexagon nut on the positive battery terminal and remove terminal.
Pull off vent hose -A- and fix in a suitable position with insulating tape.
Unscrew fastening screw -B- .

Fig 2: Identifying Battery Vent Hose & Fastening Screw

Courtesy of PORSCHE OF NORTH AMERICA, INC.