2008 Suzuki LT-A400/F, LT-F400/F ATV Service Manual, Page 216Get this manual
1J-2 Charging System: Condition Unstable charging Possible cause Lead wire insulation frayed due to vibration, resulting in intermittent shortcircuitingInternally short-circuited generatorDefective regulatorrectifierBattery overcharges Faulty regulatorrectifierFaulty batteryPoor contact of generator lead wire couplerBattery runs down quickly Trouble in charging systemCorrectionReference Item Repair or replaceReplaceReplaceReplaceReplaceRepair Battery "sulfation"
Check the generator, regulatorrectifier and circuit connections and make necessary adjustments to obtain specified charging operationCell plates have lost much of their active Replace the battery and correct the charging materials result of overchargingsystemInternal short-circuit in the batteryReplace the batteryToo low battery voltageRecharge the battery fullyToo old batteryReplace the batteryIncorrect charging rate(When not in Replace the batteryuse battery should be checked at least once month to avoid sulfation The battery was left unused in cold Replace the battery if badly sulfatedclimate for too long