Yamaha JW-II Service Manual page 39

Battery Charger
Function 2. Refresh function
Charging the battery after it has been completely discharged improves the activiation in the battery
and restores the battery performance. Also, the communication function in the XA4 charger receives
data from the battery control unit at the optimum refresh timing, and has a function which alerts the
user that refresh charging is needed. Conversely, if refresh charging is carried out too frequently, it
can damage the battery. The XA4 charger is designed so that refresh charging can only be carried
out when the refresh alert is displayed.
NOTE:
•
The timing at which the refresh alert is displayed varies depending on how the battery is used. As
a rule, the alert is displayed after 10 to 30 cycles of use.
•
If the battery is completely charged, refresh charging takes 13 to 15 hours. We recommend using the
battery as long as possible before carrying out refresh charging.
Function 3. Battery protection function
Because the service life of the battery is affected by temperature of the battery when it is charged, the
charger controls the charging process based on the battery temperature data sent from the battery
control unit.
NOTE:
•
The battery temperature must be between 0 and 40°C for charging to start.
•
If the battery temperature reaches 50°C, charging is forcibly stopped.
Function 4. Multi-input function
The XA4 charger can accommodate input power supplies of AC 100 to 240 V, 50/60 Hz. As long as
the power supply is within the above range, the charger can be used anywhere in the world. The
customer should be advised, however, that the AC plug configuration varies depending on the coun-
try.
Function 5. Communication function
In order to communicate with the battery, the XA4 charger
has a built-in communication function. Communication is
carried out through two contact points. If a problem occurs
with one of the contact points used for communication,
charging can no longer be carried out, and an error display
notifies the user of the problem.
(See the later section called "Error Displays".)
NOTE:
Problems such as deformation of a contact point or foreign
substances in the unit can make it impossible to charge the
battery.
Names and Functions of Parts
– contact point
Communication
contact points
+ contact point
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