Yamaha YP250 Service Manual page 90

Charging method using a variable-current (voltage) type charger
Charger
Adjust the voltage so that cur-
rent is at standard charging
level.
Set the timer according to the
charging time suitable for the
open-circuit voltage. Refer to
the "Battery condition check-
ing steps" section.
In case that charging requires more than 5 hours, it is advisable to
check the charging current after a lapse of 5 hours. If there is any
change in the amperage, readjust the voltage to obtain the standard
charging current.
Measure the battery open-circuit voltage after having left the battery
unused for more than 30 minutes.
12.8 V or more-Charging is complete.
12.7 V or less-Recharging is required.
Under 12.0 V-Replace the battery.
Measure the open-circuit
voltage prior to charging.
AMP meter
Connect a charger and
AMP meter to the battery,
and start charging.
Make sure the current is
YES
higher than the standard
charging current written on
the battery.
BATTERY INSPECTION
By turning the charging voltage
adjust dial, set the charging
voltage at 20 X 25 V.
Monitor the amperage for 3 X
YES
5 minutes to check if the stan-
dard charging
reached.
3-40
INSP
ADJ
NOTE:
Voltage should be measured 30 min-
utes after the machine is stopped.
NOTE:
Set the changing voltage at 16 X 17 V.
(If the setting is lower, charging will be
insufficient. If too high, the battery will
be over-charged.)
NO
current is
If current does not
exceed standard
charging current
after 5 minutes, re-
place the battery.
NO