2009 Polaris Scrambler 500 4x4 2x4 factory service manual, Page 240Get this manual
ELECTRICAL Battery Check:
1Check the date label on the side of the battery to calculate when to check voltageThe battery should be checked every months2Check the voltage with voltmeter or multimeterA fully charged battery should be 12.8 or higher3If the voltage is below 12.8 V, the battery will need to be recharged
SEALED LOW MAINTENANCE BATTERY CHARGING
If battery voltage is 12.8 or less, the battery may need rechargingWhen using an automatic charger, refer to the charger manufacturer's instructions for rechargingWhen using constant current charger, use the following guidelines for rechargingNOTE: Always verify battery condition before and 1-2 hours after the end of chargingWARNING: An overheated battery could explode, causing severe injury or deathAlways watch charging times carefullyStop charging if the battery becomes very warm to the touchAllow it to cool before resuming charging
Battery Charging Reference Table