Owner's Manual for the vehicle. With a quick reference ... - E38.org

174nBattery
Do not short circuit the battery terminals.
This creates a risk of personal injury
from high-voltage sparks.
A highly-explosive gas is
generated when the battery is
charged.
If you happen to get acid in
your eyes, rinse thoroughly for
15 minutes with clear water.
Consult a physician immediately. If you
get acid spray on your skin or clothing,
rinse with plenty of water. If electrolyte
is accidentally ingested, consult a physician
immediately.
In order to protect the battery
case from ultraviolet radiation,
do not place it in direct sunlight.
A discharged battery can freeze. Store
the battery in areas where temperature
remains above freezing.
Car care
The battery is completely maintenancefree,
that is, the original electrolyte will
normally last for the service life of the
battery.
380de655
Charge condition – BMW 740i/L
You can read the charge condition of
the battery with the "Magic Eye" (a hydrometer)
(not released at this time):
> Green: Adequate charge
> Black: Not charged adequately. The
battery must be recharged. Please
contact your BMW center
> Yellow: Replace the battery.
Charging the battery
Charge the battery in the vehicle only
when the engine is off. Charge the battery
using the supplementary positive
terminal and ground (terminal) in the engine
compartment (refer to "Jump-starting"
on page 179).
On the BMW 750iL, there is an automatic
switch between the two batteries
during charging.
Before performing any work on
the electrical system, disconnect
the cable from the negative terminal. If
you do not, short circuits can create the
risk of fire or personal injury.
If a jump start is necessary, connect the
cables only to the auxiliary terminal for
jump starting and a ground in the engine
compartment in order to avoid
damage to the batteries (refer to
"Jump-starting" on page 179).