2008 Polaris ATV Sportsman 300 400 H.O. Service Manual, Page 211Get this manual
ELECTRICAL SPECIFIC GRAVITY State of Charge 100 Charged 75 Charged 50 Charged 25 Charged Charged Conventional Lead-Acid 1.265 1.210 1.160 1.120 less than 1.100 YuMicronTM Type 1.275 1.225 1.175 1.135 less than 1.115
Battery Off Season Storage
Whenever the vehicle is not used for period of three months or more, remove the battery from the vehicle, ensure that it's fully charged, and store it out of the sun in cool, dry placeCheck battery voltage each month during storage and recharge as needed to maintain full chargeNOTE: Battery charge can be maintained by using Polaris battery tender charger or by charging about once month to make up for normal self-dischargeBattery tenders can be left connected during the storage period, and will automatically charge the battery if the voltage drops below pre-determined point