Yamaha YZ 2018 Series, Owner'S Service Manual

Page: 361 / 402

ELECTRICAL COMPONENTS
8-62
TIP
Since VRLA (Valve Regulated Lead Acid) bat-
teries are sealed, it is not possible to check the
charge state of the battery by measuring the
specific gravity of the electrolyte. Therefore, the
charge of the battery has to be checked by
measuring the voltage at the battery terminals.
1. Remove:
• Side cover (left/right)
• Seat
Refer to “GENERAL CHASSIS” on page 4-
1.
2. Disconnect:
• Battery leads
(from the battery terminals)
ECA
NOTICE
First, disconnect the negative battery lead
“1”, and then positive battery lead “2”.
3. Remove:
• Battery
4. Check:
• Battery charge
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a. Connect the digital circuit tester to the bat-
tery terminals.
TIP
• The charge state of a VRLA (Valve Regulated
Lead Acid) battery can be checked by mea-
suring its open-circuit voltage (i.e., the voltage
when the positive battery terminal is discon-
nected).
• No charging is necessary when the open-cir-
cuit voltage equals or exceeds 12.8 V.
b. Check the charge of the battery, as shown in
the charts and the following example.
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5. Charge:
• Battery
(refer to the appropriate charging method)
EWA
WARNING
Do not quick charge a battery.
• Positive tester probe

positive battery terminal
• Negative tester probe

negative battery terminal
1
2
Example
Open-circuit voltage = 12.0 V
Charging time = 6.5 hours
Charge of the battery = 20–30 %
A. Open-circuit voltage (V)
B. Charging time (hours)
C. Relationship between the open-circuit voltage
and the charging time at 20 °C (68 °F)
D. These values vary with the temperature, the
condition of the battery plates, and the electro-
lyte level.
A. Open-circuit voltage (V)
B. Charging condition of the battery (%)
C. Ambient temperature 20 °C (68 °F)