What does it mean when the dashboard shows battery positive and negative signs?
3 Answers
The dashboard displaying battery positive and negative signs indicates that the alternator is not functioning. The battery power will be depleted quickly as it cannot be recharged. The car alternator serves as the vehicle's main power source, supplying electricity to all electrical devices (except the starter) while simultaneously charging the battery when the engine is running normally (above idle speed). Currently, most vehicles use AC generators, and the following points should be noted during use: 1. Regularly clean accumulated dirt and dust from the alternator surface to maintain cleanliness and proper ventilation. 2. Frequently inspect the tightness of all fasteners related to the alternator and promptly tighten any loose screws. 3. The drive belt tension should be appropriate. If too loose, it may slip and cause insufficient power generation; if too tight, it may damage the belt and alternator bearings. 4. When installing the battery, never reverse the connections. Typically, connect the positive terminal first before connecting the ground wire, otherwise the diodes may burn out easily. 5. When using an integrated circuit voltage regulator, turn off the ignition switch immediately if the engine stops running. 6. Never test for power generation using the 'spark test' method.
After driving for so many years, I've encountered the battery positive and negative indicator on the dashboard quite often, and it mostly seems to be an issue with the charging system. The most common cause is the battery itself aging or having insufficient charge. If you frequently take short trips or start the engine repeatedly, the battery doesn't have enough time to recharge, and the low voltage triggers the warning light. Alternator failure is another frequent reason—for instance, if the alternator's voltage regulator is broken and can't charge the battery, or if the belt is loose or broken, preventing power transmission. Wiring issues shouldn't be overlooked, especially corrosion or loose connections at the terminals causing unstable current. From personal experience, if this light stays on and you keep driving, the battery will drain quickly, and the engine could stall at any moment in dangerous situations. So, I recommend turning off power-hungry devices like the AC and stereo immediately and heading to a professional shop to test the charging system with proper tools. For prevention, regularly checking the battery's age and the alternator belt's condition can save a lot of trouble.
When I see that battery light come on in the car, I always feel uneasy—it's often a sign that the charging system isn't functioning properly. Common causes include issues with the battery itself, such as it being too old or unable to store electrical energy, which leads to a rapid drop in charge. Alternator failure is also frequent; it's responsible for charging the battery, and if it breaks down or the belt wears out, charging is interrupted. For the wiring part, check the terminals for corrosion or looseness, as poor contact can hinder current transmission. Ignoring it may result in stalling midway or even being unable to start the vehicle, posing significant safety risks. For a simple self-check, you can observe whether the ignition is difficult after turning off the lights, or use a multimeter to measure the battery voltage while the engine is running to see if it drops below 12 volts. Early repairs are recommended to avoid bigger troubles—safety always comes first.
