2008 Polaris ATV Sportsman 300 400 H.O. Service Manual, Page 207Get this manual
ELECTRICAL Current DrawKey Off CAUTION
Do not connect or disconnect the battery cable or ammeter with the engine runningDamage will occur to electrical componentsConnect an ammeter in series with the negative battery cableCheck for current draw with the key offIf the draw is excessive, loads should be disconnected from the system one by one until the draw is eliminatedCheck component wiring as well as the component for partial shorts to ground to eliminate the drawCurrent Draw Inspection Key Off
Charging System "Break Even" Test CAUTION
Do not allow the battery cables to become disconnected with the engine runningFollow the steps below as outlined to reduce the chance of damage to electrical componentsThe "break even" point of the charging system is the point at which the alternator overcomes all system loads (lights, etc and begins to charge the batteryDepending on battery condition and system load, the break even point may vary slightlyThe battery should be fully charged before performing this test