2007 Yamaha Apex Factory Service Manual, Page 63Get this manual
BATTERY INSPECTION Charging method using variable voltage charger Measure the open-circuit voltage prior to chargingConnect
the standard charging levelYES Monitor the amperage for minutes to check if the standard charging current is reachedNO Set
the time according to the charging time suitable for the open-circuit voltageRefer to "Battery condition checking steps"
If the current does not exceed the standard charging current after minutes, replace the battery If charging requires more
than hours, it is advisable to check the charging current after lapse of hoursIf there is any change in the amperage, readjust
the voltage to obtain the standard charging currentMeasure the battery open-circuit voltage after leaving the battery unused