Porsche 968 Driver Manual page 85

Checking and Servicing the
Batte
I)'
The battery is in the engine compartment, on
the right-hand side behind the bulkhead.
On right-hand drive vehicles the battery is lo-
cated in the luggage compartment in the left-
hand stowage recess.
Because of the danger of short-circuits, always
disconnect the battery before beginning work on
the electrical system. To do so, disconnect the
battery earth strap.
Disconnecting the battery whilst the engine is
running can destroy the alternator and the
control units. This also applies accordingly to
vehicles with a built-in battery disconnection
switch.
If the battery is disconnected, the data stored in
the control units are erased and must be reen-
tered when the battery has been reconnected
(e.g. anti-theft code for the radio). After recon-
nection, the control unit for the engine electro-
nics takes about 1 0 minutes with the engine run-
ning to reacquire the requisite data. During this
time, the engine may idle unevenly or too fast.
A well charged battery helps to prevent starting
problems and has a longer service life. Increas-
ing traffic density, speed limits and legislation of
noise, exhaust gas and fuel consumption, how-
92
ever, mean that the alternator cannot turn as
often and its output is correspondingly lower.
The growing amount of electrical equipment, by
contrast, results in more current being required .
Therefore check, especially when only mak-
ing short journeys, that all unnecessary elec-
trical systems are turned off.
If your Porsche is left unused for an extended
period in a garage or at a workshop, the doors
and the front and rear lids should be closed .
Remove the ignition key or, if appropriate, dis-
connect the battery. The alarm is deactivated
when the battery is disconnected!
Removing the Battery
The necessary wrenches for removing the bat-
tery are in the tool kit. When removing the bat-
tery, first disconnect the negative cable, and
when installing the battery, first connect up the
positive cable.
Winter Operation
The battery capacity is reduced by low tempera-
tures. Moreover, during the winter months, the
demands made on the battery increase due to
the rear window heating and more frequent use
of additional lights, the blower, the windscreen
wipers etc.
Therefore, before the winter sets in, have the
condition of your battery checked at an Official
Porsche Centre. To prevent the battery from
freezing, it should always be fully charged. A flat
battery can freeze at only -1
oo c,
while a fully
charged battery will not freeze until the tempera-
ture is down to --40°C.
Care of the Battery
The battery terminals must be kept clean. Check
that the battery plugs and terminal clamps are
seated correctly.
Checking the Electrolyte Level
Unscrew all plugs. With the car on a level sur-
face, the electrolyte in each cell must reach the
filling mark. These filling marks can be seen
through the plug apertures as bars or lugs in
the battery. There are also marks for the elec-
trolyte level on the outside of the battery casing.
The electrolyte level can be recognised by its
dark colouring through the sides of the cells. If
the electrolyte level requires adjustment, use
only distilled water (never acid). Be careful to
use a clean vessel when topping up the battery.
On no account must alcohol (e.g. window
cleaner residue) be allowed to get into the bat-
tery. Never add more liquid than necessary.
Electrolyte should be checked more frequently
during the summer and in hot climates .