At what voltage should I replace my car battery?
At what voltage should I replace my car battery?
The battery must maintain a minimum post voltage of 9.6 Volts at 70 degrees F during the test to pass. If the voltage drops below 9.6 volts, the battery is “bad” and needs to be replaced.
What should the voltage be on a bat alternator?
Measure the voltage across the battery and the big bat alternator terminal to alternator case. There are two things that you are looking for. The charging voltage should be between 13.9v to 14.4v. Also the voltage at the battery and the voltage at the alternator should be within 0.5v of each other.
What to do if your alternator is over charging the battery?
Ask an assistant to start the engine and hold engine speed at about 1500 RPM. Measure voltage across the battery with your DMM. You should get 0.5 to 2 volts higher than base voltage. If you are getting more than 2 volts above base voltage, most likely your alternator is over-charging the battery or the battery is faulty.
What does 12.6 volts mean on a battery?
Also, most modules on a vehicle will set a code if low system voltage is detected. The rule of thumb that states 12.6 volts equals a fully charged battery and 12.2 volts means it is 25 percent charged, is starting to change with some modern batteries and charging systems.
Where can I get a 12V alternator tester?
Decided to go to O’Reilly Auto Parts and try their charge system tester. The use the same tool as AutoZone, a tool by a company named AutoMeter BVA-260, but re-branded AutoZone. #1468 12V ALTER.
What should the charge voltage be on an alternator?
Turn on the high beams for 10 seconds and then turn them off. Measure battery voltage across the battery posts with your DMM. You should get between 12.4 and 12.6V. This means your battery is fully charged. If you get a reading below 12.4V, charge the battery before continuing. 5b. Measure the Charging System’s No-Load Voltage
Also, most modules on a vehicle will set a code if low system voltage is detected. The rule of thumb that states 12.6 volts equals a fully charged battery and 12.2 volts means it is 25 percent charged, is starting to change with some modern batteries and charging systems.
Can a car battery be drained by an alternator?
While you might initially think that any problems with electrical things like lights or radio not working are directly related to the battery, the alternator is actually where most of the power in your vehicle comes from. Consider that if you were to leave the lights of your car on overnight by the next day your battery might be drained completely.
When does the alternator light turn on the battery?
On older vehicles, the battery light would turn on the alternator light when the alternator output or battery voltage dropped below a preset value. The battery light on modern vehicles, however, is controlled by data and trouble codes. This is why a scan tool is essential to diagnosing a charging system.
