Porsche Boxster Owner's Manual page 242

Electrical system
Remove the battery from the vehicle and store
it in a cool dry place, not on a cement floor.
When the battery is disconnected, the
alarm system is deactivated.
Recharge the battery every 3 months. If the
battery remains in the vehicle with the cables
connected, it is necessary to check, remove
and recharge the battery every 2-3 weeks. Do
not fast charge the battery.
Please observe the chapter "BATTERY" on
page 268.
Vehicle interior
The interior must be dry, especially in the area
of the floor carpets. The use of drying agents
(Silica-Gel) is recommended in vehicles with
leather interior and in areas with high humidity. The
recommended amount is 3 fabric bags of 1.1 lbs.
(500 grams) each placed on the floor carpets.
Windows, doors, lids and top must be closed. The
air vents should be opened.
240
Maintenance, Car Care