How to Use Connect two crocodile clips to a 12V DC source from the battery; the red indicator will be on. Insert the plug into the OBD port of the car; you will hear a continuous beeping. You can then remove the old battery from the car and install the battery. Compatibility and Display The memory saver works with any 12V DC power source, including a car battery (including running starters), battery memory saver DC 12V acid batteries or automotive DC 12V power outlets. It displays voltage and current; the memory saver uses red to indicate voltage and green to indicate current. Protection and Safety Features Includes reverse connection protection, wrong connection protection, self protection, leakage detection, and related safeguards. Important Usage Note If the original vehicle battery power loss is serious, using the tool may behave as charging the original vehicle battery directly; current can reach a few amps to dozens of amps. Because the tool fuse is 5A, the fuse may blow, which would prevent the battery replacement from proceeding without power being interrupted. Correct practice: connect to the original vehicle battery power, restart, and ensure the power is fully restored before performing the replacement. Use Scenarios Scenario 1: Replacing a car battery in a vehicle while preserving ECU and radio memory, using an external 12V source to power the memory saver during the swap. Scenario 2: In a or field service, using a portable 12V power source to support memory retention while changing a discharged or worn battery. Scenario 3: Routine maintenance where the original battery is disconnected, ensuring continuous monitoring of voltage and current to confirm the system is ready for battery replacement.