Page 300 of 498

299 Operation
Engine compartment
Battery
Your vehicle is equipped with two batter-
ies:
Auxiliary battery (located in the engine 
compartment).
Main battery (starter and electrical 
consumers; located in the trunk) 
(page 431).
The batteries should always be sufficiently 
charged in order to achieve their rated ser-
vice life. Refer to Maintenance Booklet for 
battery maintenance intervals.
If you use your vehicle mostly for short-dis-
tance trips, you will need to have the bat-
tery charge checked more frequently.
When replacing the battery, always use 
batteries approved by Mercedes-Benz.
If you do not intend to operate your vehicle 
for an extended period of time, consult an 
authorized Mercedes-Benz Center about 
steps you need to observe.Batteries contain materials that can harm 
the environment if disposed of improperly. 
Recycling of batteries is the preferred 
method of disposal. Many states require 
sellers of batteries to accept old batteries 
for recycling.
G
Observe all safety instructions 
and precautions when handling 
automotive batteries.
A
Risk of explosion.
D
Keep flames or sparks away 
from battery. Do not smoke.
B
Battery acid is caustic. Do not 
allow it to come into contact 
with skin, eyes or clothing. 
In case it does, immediately 
flush affected area with clean 
water and seek medical help if 
necessary.
E
Wear eye protection.
C
Keep children away.
F
Follow the instructions in this 
Operator's Manual. 
     
        
        Page 432 of 498

431 Practical hints
Battery
Battery
Your vehicle is equipped with two batter-
ies:
Auxiliary battery (back-up battery; sta-
bilizes the electrical system if the main 
battery is discharged; located in engine 
compartment).
Main battery (starter and electrical 
consumers; located in the trunk under 
the luggage box).
Remove the luggage box (
page 401).
1Positive terminal cover
2Negative terminal
Warning!
G
Jump starting must only be done using the 
main battery in the trunk.Warning!
G
Failure to follow these instructions can 
result in severe injury or death.
Observe all safety instructions and precau-
tions when handling automotive batteries 
(page 299).
Never lean over batteries while connecting, 
you might get injured.
Battery fluid contains sulfuric acid. Do not 
allow this fluid to come in contact with eyes, 
skin or clothing. In case it does, immediately 
flush affected area with water and seek 
medical help if necessary.
A battery will also produce hydrogen gas, 
which is flammable and explosive. Keep 
flames or sparks away from battery, avoid 
improper connection of jumper cables, 
smoking etc.!Never loosen or detach battery termi-
nal clamps while the engine is running 
or the SmartKey is in the starter switch. 
Otherwise the alternator and other 
electronic components could be se-
verely damaged.
Have the battery checked regularly by 
an authorized Mercedes-Benz Center.
Refer to Maintenance Booklet for main-
tenance intervals or contact your 
authorized Mercedes-Benz Center for 
further information. 
     
        
        Page 459 of 498
458 Technical dataElectrical systemModel
CLS 500
CLS 55 AMG
Generator (alternator)
14 V/150 A
14 V/180 A
Starter motor
14 V/1.7 kW
14 V/1.4 kW
Battery (auxiliary)
12 V / 12 Ah
12 V / 12 Ah
Battery (main)
12 V/95 Ah
12 V / 95 Ah
Spark plugs
Bosch F8 DPP 332U
NGK PFR 5R-11
NGK IL FR6 A
Electrode gap
0.039 in (1.00 mm)
0.031 in (0.8 mm)
Tightening torque
18.5 - 22 lb-ft (25 - 30 Nm)
18.5 - 22 lb-ft (25 - 30 Nm)