What Causes a Car to Stop Generating Electricity?
3 Answers
Here are the reasons why a generator may not generate electricity and their solutions: 1. The generator belt is broken or slipping, causing the issue. Tighten the adjustment device or replace the belt; 2. There is an open circuit in the generator output wire. Check the condition of the wire; 3. The rotor part is stuck. Manually test if it rotates smoothly. Below are methods to determine if the engine has a fault: 1. Use a multimeter in voltage mode. Set the multimeter knob to the 30V DC voltage range, connect the red probe to the generator's 'armature' terminal, and the black probe to the casing. Run the engine at medium speed or higher. The standard voltage for a 12V electrical system should be around 14V, and for a 24V electrical system, it should be around 28V. If the measured voltage is the same as the battery voltage, it indicates the generator is not generating electricity. 2. Use an external ammeter for testing. If there is no ammeter on the car dashboard, an external DC ammeter can be used for detection.
When I was driving an old car before, I noticed that the car wasn't generating electricity, and the battery warning light on the dashboard came on. I asked a mechanic, and he said common causes include alternator failure, such as worn brushes or internal short circuits, leading to insufficient power supply; a loose or broken alternator belt—if the belt issue is severe, the car won't charge at all while running; a damaged voltage regulator, which controls voltage stability—if it fails, the voltage becomes unstable; an aging battery or oxidized terminals—though the issue lies with the battery, it's often mistaken for a charging problem; and poor electrical connections, such as blown fuses or loose plugs. In my case, after checking, it turned out the belt was broken, and replacing it fixed the issue. Usually, paying attention to the belt condition and dashboard warnings while driving can help detect problems early and avoid breakdowns on the road.
As someone who enjoys tinkering with cars, when I encounter a charging issue, I start with the simplest checks. First, I look to see if the alternator belt is loose or cracked, as this is a common culprit. Then, I inspect internal components of the alternator, such as the brushes or coils, for wear, which can impede power generation. Next, I use a voltmeter to test the battery voltage—if it's below 13 volts while the engine is running, it indicates a problem with the regulator or alternator. Don’t forget the fuses in the fuse box; a blown fuse can disrupt the entire circuit. Finally, check for loose wiring connections. Wearing gloves while working on the car is safer, and regularly cleaning dust from the engine bay can extend its lifespan. Checking the belt tension during each maintenance session can save a lot of trouble.
