2008 Yamaha Raptor 250SE / 250SE2 Factory Service Manual, Page 109Get this manual
CHECKING AND CHARGING THE BATTERY Charging method using variable-current (voltage) charger
Charger Ammeter
Measure the open-circuit voltage prior to charging
Leave the battery unused for more than 30 minutes before measuring its open-circuit voltage
Connect charger and ammeter to the battery and start charging
Set the charging voltage to 1617 V(If the charging voltage is lower, charging will be insufficient, if it is higher, the battery will be over-charged
Is the amperage higher than the standard charging amperage written on the battery?