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Can a car battery be bad even if it reads 12 volts?
If your battery is reading 0 volts, chances are the battery experienced a short circuit. 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.
How many volts should my car battery lose overnight?
If you measure the voltage immediately after the end of a drive, it should be more like 13.2, and drop to 12.7 within a few minutes as the chemical reactions in the battery slow down and stop when you stop charging it.
Will a car start with 11.5 volts?
There is no exact answer to the question. In the standard state, a fully charged battery should show a 12.6-12.7V. In this case, the voltage is difficult to estimate, but it also slightly falls down, and if it is less than 11.5V, then it indicates that the battery is discharged by 50%.
Why is my car battery only at 12.5 volts?
Your battery is not holding its charge. The reason it is showing 12.5 volts after a 20 minute drive is because your alternator has been attempting to charge it to its maximum, (12.7volts). However even at 12.5 volts it is only 90% charged.
What should car battery voltage be After sitting overnight?
I wouldn’t say 10 volts because if it gets that low either the battery is dead flat or it has a dead cell in it,at 11 volts is flat & 12 volts is half charged ! If the battery was healthy, and fully charged, then tested for 24 hours, it should not be less than about 12.8 Volts. If it’s much less, it is likely faulty.
What is the true voltage of a car battery?
However even at 12.5 volts it is only 90% charged. Vehicle batteries should be tested for their true voltage level only after they have been allowed to stand, after and off charge for about 30 minutes. As yours is only showing a level of 11.8 volts it is only 35% charged and indicates a dud cell.
Why is my car battery so low in the morning?
If it’s more than 1-2v volts lower, then probably bad alternator function (which can be caused by a loose or deteriorated belt – may not need a new alternator) or some hefty accessory usage. If it’s more than 14.5~15v while idling then there is a strong possibility the alternator is outputting too much voltage and adversely damaging the battery.