What is the situation when the battery has power but the entire vehicle has no power?
2 Answers
Loose battery group plugs, broken internal battery connection wires, short circuits in the wiring, blown fuses, or the vehicle's power-off switch not being turned on can all cause the battery to have power but the entire vehicle to have no electricity. Related information: The red terminal of the battery is the positive pole, and the black one is the negative pole. The batteries are connected in series inside the battery box, meaning the positive pole of one battery is connected to the negative pole of another battery. Following this connection method, there will eventually be one positive and one negative lead wire left, which should be connected to the battery discharge port. Pay attention to the correct correspondence, generally left positive and right negative. Be cautious to avoid short circuits when connecting the batteries. If water enters the battery in a short time, it will not affect the battery's performance, as water is a weak electrolyte with very low conductivity. However, it must be wiped dry immediately; otherwise, the terminals may oxidize, causing them to fall off and damage the battery.
A few days ago, I encountered this situation when driving out—the battery was fully charged, but the car just wouldn’t start, and even the dashboard wouldn’t light up. It was incredibly frustrating. Possible causes include loose or corroded battery terminals, where the screws aren’t tightened enough to allow current flow; or a blown main fuse, which is especially common in older cars; a faulty relay can also cause a complete power loss, such as when the component controlling the main switch fails. At the time, I tried cleaning the terminals with sandpaper, but it didn’t help much. Later, at the repair shop, I found out the corrosion was too severe, so I had to replace the parts. I recommend paying attention to cleaning the connections during regular maintenance, keeping them dry, and definitely not waiting until a major problem arises—breaking down on the road is dangerous. Keeping a small toolkit in the car can be very handy.
