Porsche 928 1980 Owner's Manual page 65

Battery-12 Volt
The battery is located underneath the col-
lapsible spare tire in the luggage compart-
ment. The battery is accessible after taking
out the spare tire.
Before work is done on the electrical sys-
tem, the battery must be disconnected to
prevent short circuiting. First disconnect the
negative ground wire at body (arrow) and
then the positive cable. To reconnect bat-
tery, reverse the procedure.
64
Disconnecting the battery while the en-
gine is running will damage the alter-
nator. This also applies to cars equipped
with a battery main switch.
Checking the electrolyte fluid level
The electrolyte fluid level in your battery can
be checked by unscrewing and opening the
filler vent caps of each cell. The fluid level
should meet the indicator mark in each cell.
If necessary, top up with distilled water.
Caution: Do not expose battery to open
flame or electric spark as hydrogen gas
generated by the battery is explosive. Do
not let battery acid come in contact with
skin, eyes, fabric or painted surfaces.
If you get electrolyte acid in your eyes or
on your skin, immediately rinse with
cold water for several minutes and call a
doctor.
Battery care
- battery should be securely mounted
- terminals and connections should be kept
clean and securely tightened. Corrosion
can be prevented by coating terminals
and connections with petroleum jelly or
silicone spray
- vent caps must be securely tightened to
prevent spillage
- spilled electrolyte fluid should be rinsed
off at once with a baking soda and water
solution to neutralize the electrolyte acid
and to prevent damage to fabric and metal.
Keep your battery in the best possible
condition at all times.
During the winter months, battery capacity
tends to decrease as temperatures drop,
and headlights, heater, rear window defog-
ger, etc., are used more frequently. Curtail
unnecessary power consumption, particu-
larly in city traffic or when traveling short dis-
tances only.
Automotive batteries lose their efficiency
when not in use. The charge available in
your battery can be measured with a hydro-
meter. We recommend that battery voltage
be tested by your Porsche dealer who has
the appropriate equipment. If the car is not
driven for prolonged periods, the battery
must be charged at least every 6 weeks. A
discharged battery allows rapid formation of
sulfates, leading to premature deterioration
of the plates.