2012 Sportsman 400/500 and EFI Tractor Service Manual 9923412, Page 413Get this manual
ELECTRICAL Off Season Storage
To prevent battery damage during extended periods of non-use, the following basic battery maintenance items must be performed: Remove the battery from the machine and wash the case and battery tray with mild solution of baking soda and waterRinse with lots of fresh water after cleaningNOTE: Do not get any of the baking soda into the battery or the acid will be neutralized Using wire brush or knife, remove any corrosion from the cables and terminals Make sure that the electrolyte is at the proper levelAdd distilled water if necessary Charge at rate no greater than 110 of the battery's amphr capacity until the electrolyte's specific gravity reaches 1.270 or greater Store the battery either in the machine with the cables disconnected, or store in cool placeNOTE: Recharge to full capacity every 30 to 60 days during non-use periodIf the battery is stored during the winter months, electrolyte will freeze at higher temperatures as the battery dischargesThe chart below indicates freezing points by specific gravity