2004-2005 660 Yamaha Rhino Factory Service Manual, Page 123Get this manual
CHECKING AND CHARGING THE BATTERY Charging method using variable-current (voltage) charger
NOTE: Measure the open-circuit voltage prior to chargingAmmeter Connect charger and ammeter to the battery and start charging
Leave the battery unused for more than 30 minutes before measuring its open-circuit voltage
Charger
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?