Can a battery read fully charged and still be bad?
If the battery cannot reach higher than 10.5 volts when being charged, then the battery has a dead cell. If the battery is fully charged (according to the battery charger) but the voltage is 12.5 or less, the battery is sulfated. If your battery cannot even reach a full charge, consider it bad.
What happens when a car battery is fully charged?
A fully charged battery will sit idle at 12.6 volts; 2.1 volts per six internal cells. Once the vehicle is started without the introduction to a load (lights, radio, A/C and fan), the volts will rise to an average of 14 volts.
Can a completely dead battery be recharged?
There are a few ways to recharge your battery, though the phrase “completely dead” is a bit more difficult to assess. If your car does not start because of a completely dead battery, your only option might be to get a jump start from another car and purchase a new battery in the near future.
Why is the battery on my car dead?
I went to jump start it this morning, ran it 20km ( 30 minutes ) to work and after turning it off, the battery is 100% DEAD. I can’t even engage the door locks it’s so dead. It appears that the alternator just isn’t charging the battery at all.
What does it mean when a car battery is not charged?
The battery is shot. The charger indicating a fully charged battery means one of two things: the battery is fully charged, or the battery is faulty and won’t take a charge. A battery that has sat for a month and then expended some energy trying to start the engine is not going to be fully charged.
Can a bad alternator drain a car battery?
A car alternator recharges the battery and powers certain electrical systems like lights, radio, air-conditioning, and automatic windows. If your alternator has a bad diode, your battery can drain. The bad alternator diode can cause the circuit to charge even when the engine is shut off, and you end up in the morning with a car that won’t start.