The density of the electrolyte is not inspected and adjusted, especially when winter comes, resulting in insufficient battery capacity and even freezing of the electrolyte. When using the battery to start in winter, use the starter uninterruptedly, causing the battery to be damaged due to over-discharge. In order to prolong the service life of the battery and avoid breakdowns such as breakdown, we should pay attention to the following points in the maintenance of the battery: 1. For maintenance-free batteries, always check the color of the electric eye. Green means the battery is sufficient; black means the battery is insufficient and need to be recharged; gray or light yellow means the electrolyte is insufficient, because the maintenance-free battery cannot be filled, the battery should be replaced immediately. 2. The battery should be securely placed on the car to prevent the battery cable from falling off due to vibration during driving, causing power supply to be interrupted. 3. Keep the surface of the battery clean. If solid oxide is found on the pole, it should be washed with hot water in time to remove it, so as not to affect the continuity between the pole and the terminal. After cleaning, wipe the surface of the battery clean, and put butter on the pole and terminal to ensure that the pole is not oxidized. 4. Check the height of the electrolyte at least once a month. For batteries without a marking line, the electrolyte can be added to a height of 10-15mm above the plate; for batteries with two red lines, the electrolyte must not exceed the upper red line, otherwise the electrolyte may overflow and form self-discharge between the positive and negative electrodes. Make the engine difficult to start, and shorten the battery life. 5. Adjust the concentration of electrolyte according to different regions and seasons. In the winter in our northeast, the concentration of electrolyte must reach 1.28 g/ml. 6. Cars that have not been used for a long time should be started every month or so, and run at a medium speed for about 20 minutes, otherwise the car will be left for too long and the car will not start when the car is in use. 7. The total length of each start of the car should not exceed 5 seconds, and the interval between restarts should not be less than 15 seconds. In the case that the car cannot be started after repeated starts, the reasons should be found from other aspects such as the circuit, ignition coil or oil circuit, and the engine should be started after troubleshooting. Otherwise, the battery will be over-discharged and affect the service life.