Can batteries test good but be bad?
As long as battery voltage remains above 9.6 volts, the battery is considered “good.” But if it drops below 9.6 volts by the end of the test, the battery may be “bad,” or the battery may have to be recharged and retested if it was not fully charged prior to the test.
Why is my battery light on if my battery is good?
An illuminated battery light could be due to a number of issues, including: A loose or corroded battery cable. A problem with the alternator or voltage regulator. Damaged cells or plates inside the battery.
How do you check if a battery is good with a multimeter?
Connect the multimeter to the positive and negative battery terminals. If you don’t have a voltage of around 12.6 volts, you may have a bad battery. Now start the car, and look for a revised voltage over 10. If your voltage drops below 5 when the car is running, it is bad and should be replaced right away.
Can you use a 12V test light on a bad battery?
You can substitute a 12v test light, it obviously wont work as well, but it works. Be sure to test the bulb across both terminals of the battery first. Disconnect the earth cable, charge it, and leave the earth diconnected overnight. See if it’s still good in the morning.
Can a bad battery test as being good?
Batteries tested fine. Someone finally told me that while batteries can test out okay – they can lose some of their capacity for “cold cranking amps”. I replaced them and all was fine again. I keep my old batteries in my garage. I still work them like a dog for emergency auxiliary power sources when the power goes down during storms.
What does it mean when the Battery Light is on?
Check to make sure the wire is not broken. This is the same connector that lets the on-board computer know if the alternator is charging or not, which is what the battery light actually means. You can use a volt meter to test what the battery is receiving by connecting it to the middle of the posts while the engine is running.
What’s the best way to test a battery?
Disable either the fuel or ignition system — whichever is easiest on your vehicle. This is necessary because the test is dependent on the vehicle cranking, but not starting. Place the positive multimeter lead on the positive battery terminal and the negative lead on the negative terminal.