Operator’s Manual Vehicle Maintenance CXU, CHU, GU, TD, MRU and LEU 41 Battery Warmer A battery warmer can be added to raise the temperature of the battery core and facilitate quick starting in cold weather. Battery Condition The first procedure when testing a battery is to check for external damage such as a cracked case, loose or corroded terminals, or signs of excessive gassing or overcharging. A battery must be fully charged before a load test is performed. Test the battery with a hydrometer to determine the level of charge. On maintenance-free batteries equipped with a built-in hydrometer (eye), the battery condition is interpreted as follows: Battery Condition W0054088