* Car batteries use sulfuric acid. Universal indicator is designed to test the pH of solutions, but the high concentration of sulfuric acid in a car battery is extremely corrosive. It would damage the indicator and be very dangerous to handle.
* Car batteries are sealed. You can't access the electrolyte inside a car battery with universal indicator.
Testing a car battery:
If you want to test a car battery, you need a voltmeter or hydrometer. A voltmeter measures the battery's voltage, which tells you if it's charged. A hydrometer measures the specific gravity of the electrolyte, indicating the battery's charge level.
Important: Be cautious when handling car batteries. Sulfuric acid is extremely dangerous.
