Frequent question: Can a fully charged car battery 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.

Can a battery read 12V and still be bad?

A bad battery could very well produce 12+volts without a load. Rather it is voltage under a load that is important. If the battery is bad, then you would notice the lights going REALLY dim when you try to start the car.

How long should a fully charged car battery last?

Most car batteries which are in good condition will last at least two weeks without needing you to start the car and drive to recharge it, according to the AA. But if you don’t intend to drive your car for some time for whatever reason, you should still start it up once a week to recharge the 12V battery.

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How can you tell if your car battery is going bad?

The most common symptoms that come with a bad battery include:

  1. Battery light illuminated on the dashboard.
  2. Engine cranks slowly when starting.
  3. Vehicle requires frequent jump starts.
  4. Clicking when you turn the engine.
  5. Lights are dim.
  6. Car won’t start.

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Can a bad battery still read good?

Yes, it could test out okay and still have problems. That is what my batteries did before I replaced them. … 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.

Does revving the engine charge the battery?

Yes, it was true then, and it’s true now. The battery will charge faster if you rev the engine faster. And the faster the alternator turns, the more electricity it produces to run all the electrical stuff in the car — and recharge the battery. …

How long can a car sit without being driven?

Don’t let your vehicle sit idle for more than two weeks – at least get your vehicle started and get it running for a while. You’ll end up saving yourself time and money on repairs, and you’ll ensure that your vehicle is ready to go once you need it again.

How often should I start my car to keep the battery charged?

All the experts Business Insider spoke with recommended starting a car once per week to prevent a dead battery. While idling your car may be better than nothing, actually driving your car is the best way to recharge a battery in a timely manner, even if it’s just around the block a few times.

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What causes a car battery to die quickly?

Some of the most common reasons for a car battery to die repeatedly include loose or corroded battery connections, persistent electrical drains, charging problems, constantly demanding more power than the alternator can provide, and even extreme weather.

How do you tell if its your starter or your battery?

When you attempt to start the car, there is a low whining sound. If jump starting gets your engine started and running, but the car will not start again once you turn it off, the battery is probably the problem.

What is the life of car battery?

The life expectancy for your car battery is typically between four to six years. Several factors determine how long your battery will last, for example weather conditions, vehicle type and driving habits.

What should a 12 volt battery read when fully charged?

A fully charged battery will typically display a voltmeter reading of about 12.6 to 12.8 volts. If your voltmeter is showing a voltage anywhere between 12.4 and 12.8, that means your battery is in good shape. Any voltage above 12.9 volts is a good indicator that your battery has excessive voltage.

How many volts should a car battery lose overnight?

tage . A car alternator will charge your battery at around 13.5 volts with no load (headlights, A. C., etc). The at rest voltage once you stop your engine should go down to around 12.4 volts.

What voltage is too low for a 12 volt battery?

12.0 volts or below – At 12.0 volts your battery is considered to be fully discharged or ‘flat’ and should be recharged as soon as possible. The lifespan of your battery will be severely affected if it remains within this voltage range for extended periods of time.

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