The battery must be completely charged and the terminals should be properly cleaned and inspected before diagnostic procedures are performed. (Refer to 8 - ELECTRICAL/BATTERY SYSTEM - CLEANING) for the proper battery cleaning procedures. (Refer to 8 - ELECTRICAL/BATTERY SYSTEM - INSPECTION) for the proper battery inspection procedures. Refer to Standard Procedures for the proper battery charging procedures.The Micro 420 automotive battery tester is designed to help diagnose the cause of a defective battery. Follow the instruction manual supplied with the tester to properly diagnose a vehicle. If the instruction manual is not available refer to the standard procedure in this section, which includes the directions for using the Micro 420 battery tester.The OTC One Step Battery Analyzer and Charger is designed to help diagnose the cause of a defective battery. Follow the instruction manual supplied with the tester to properly diagnose a vehicle.If the battery shows signs of freezing, leaking or loose posts, do not test, assist-boost, or charge. The battery may arc internally and explode. Personal injury and/or vehicle damage may result.Explosive hydrogen gas forms in and around the battery. Do not smoke, use flame, or create sparks near the battery. Personal injury and/or vehicle damage may result.The battery contains sulfuric acid, which is poisonous and caustic. Avoid contact with the skin, eyes, or clothing. In the event of contact, flush with water and call a physician immediately. Keep out of the reach of children.Never exceed 14.4 volts when charging a spiral cell battery. Personal injury and/or battery damage may result.A battery that will not accept a charge is faulty, and must be replaced. Further testing is not required. A fully-charged battery must be tested to determine its cranking capacity. A battery that is fully-charged, but fails the OTC One Step Battery Analyzer and Charger or other load test, is faulty and must be replaced.Completely discharged batteries may take several hours to accept a charge. Refer to Standard Procedures for the proper battery charging procedures.