2005 Polaris Sportsman 400/500 Service Manual, Page 287Get this manual
ELECTRICAL NOTE: New Battery: Battery must be fully charged before use or battery life will be significantly reduced 10-30 of the battery's full potentialTo activate new battery: 1Remove vent plug from vent fittingRemove cell caps2Fill battery with electrolyte to upper level marks on case3Set battery aside to allow for acid absorption and stabilization for 30 minutes4Add electrolyte to bring level back to upper level mark on caseNOTE: This is the last time that electrolyte should be addedIf the level becomes low after this point, add only distilled water5Charge battery at 110 of its amphour ratingExamples: 110 of amp battery.9 amp; 110 of 14 amp battery1.4 amp; 110 of 18 amp battery1.8 amp (recommended charging rates)6Check specific gravity of each cell with hydrometer to assure each has reading of 1.270 or higherInspect the battery fluid levelWhen the battery fluid nears the lower level, remove the battery and fill with distilled water only to the upper level lineTo remove the battery:
Maintain between upper and lower level marks