Can the battery be charged directly in the car?
2 Answers
It is possible to charge the battery directly in the car. When starting the car, the starter requires a large current, which a regular charger cannot provide. If the battery is dead, the car won't start. The principle of charging is that the voltage must be about 20% higher than the battery's voltage to charge it effectively. Too high a voltage can damage the battery, while too low a voltage won't charge it. Uses of car batteries: 1. For starting and lighting in cars, motorcycles, tractors, diesel engines, etc.; 2. As backup power for protection and automatic control in communications, power plants, and computer systems; 3. As power sources for various battery-powered vehicles, forklifts, and loaders; 4. For starting and lighting power in diesel locomotives, electric locomotives, and passenger trains.
I've been driving trucks for over a decade, and charging directly in the vehicle depends on the situation. If the engine is still running, the alternator can automatically recharge the battery, effectively charging while driving. However, if the battery is completely dead, idling alone won't cut it—you need to rev the engine to at least 1500 RPM for effective charging. In neutral gear, the alternator basically doesn't work, and you won't get any charge in P or N gear. I once tried charging in neutral for two hours during a delivery run, only to waste gas. For emergency charging, remember to keep the engine running at medium to high speed for at least half an hour, and turn off power-hungry accessories like AC and headlights. If a battery over 3-4 years old won't hold a charge, it's probably time for a replacement.
