A battery cannot be accurately tested until it is at or near a fully charged state. Disconnect the negative battery cable and perform the following tests: visually inspect the indicator eye on the battery; if dark, charge the battery. For batteries with removable caps, check the electrolyte level, ensuring it is above the plates, and add distilled water if low, avoiding overfilling. Test the specific gravity of the electrolyte with a hydrometer, aiming for approximately 1.270 at 68-degrees F. For the open circuit voltage test, connect a digital voltmeter to the battery terminals; a fully charged battery should indicate at least 12.6 volts. An accurate battery load test requires a load tester, which evaluates the battery's ability to handle heavy amperage draw; maintain the load for 15 seconds, ensuring the voltage does not drop below 9.6 volts. For the battery drain test, ensure all accessories are off, then connect a digital ammeter to check for a drain of approximately 100 milliamps or less, identifying excessive drains by removing fuses one at a time. When replacing the battery, always disconnect the negative cable first and reconnect it last, loosen the negative cable clamp, remove the negative cable, then the positive cable, and the hold-down strap before lifting out the battery. Inspect the battery tray for corrosion and clean it if necessary. Ensure the new battery matches the original specifications, tighten the hold-down nuts securely, and reconnect the positive cable first followed by the negative cable.