Do alternators charge at idle?

Assuming the alternator, engine, belt, and battery are all in working order, then yes, a car battery will charge when idling. The only caveat is that it doesn't really “charge” that fast. This is solely due to the fact that the engine doesn't have a load on it when your car is simply idling.
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At what RPM does the alternator charge the battery?

Alternator may not generate sufficient charging voltage until alternator speed is greater than about 2000 RPM. Typically, alternators have their full output rated at 6000 RPM but can continue to spin up to 12,000 RPM or more without any additional increase in output.
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Does alternator run at idle?

Most modern vehicles control the alternators field coil and idle RPM to optimize the alternator's output. Most economy vehicle ECU minimize fuel consumption and thus alternator output at idle providing just what's needed to keep the vehicle running while stopped with minimal charging if any.
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Does an alternator charge all the time?

While the battery supplies the electricity needed for that initial spark, it only has enough power to get the car a few miles down the road, and that's where the alternator comes in—it continually charges the car battery while the car is in motion while also simultaneously operating all the electronic components of the ...
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Is idling enough to charge battery?

Idling: it's far from ideal.

While idling older vehicles for 15-20 minutes may give them enough of a charge to restart, this approach is generally not recommended. Many modern cars are equipped with sophisticated battery management systems that are designed to help extend battery life.
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At idle speed the alternator was not working.



How long should I idle my car to charge the battery?

Remember: After you've done a jump start, you'll need to keep the vehicle's engine running for around 30 minutes to allow the alternator time to charge the battery sufficiently.
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Does revving the engine charge the battery?

Yes, revving the engine will still charge the battery faster.
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Does the alternator charge the battery when the car is not moving?

yes, electrical power would be being used, but with key on/engine running (engine running, but vehicle in park or neutral), the alternator will be charging the system (battery), so battery will not 'die' like it could if vehicle ignition was in key on/engine off.
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What should a 12v alternator charge at?

A car alternator needs to be putting out at least 13-14 volts (ideally between 13.8 and 14.2 volts) to effectively charge a 12 volt car battery. If the alternator is putting out too much voltage (15+ volts), it is likely your battery acid will boil over out of the battery.
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Why does my alternator not charge at idle?

The most common reason an alternator is not charging the battery is due to worn carbon brushes or a damaged alternator itself. It can also be caused by a blown fuse or bad wirings. If your serpentine belt snapped off, the alternator will, of course not charge then either.
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Does alternator voltage change with RPM?

As most rodders know, alternators have greater output at higher speeds. This increase in output is not linear but is actually a curve. This means that as rpm changes, the alternator will increase and decrease its output at different rates.
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Is 14.7 volts too high?

14.8 would start to be a worry (there might be liquid or corrosion on the battery) and 15 volts would be a real concern, but 14.6 is fine. Less than 14.3 would be a "weak" alternator or regulator. Much less than 14.2 at a fast idle is bad wiring, bad alternator or regulator, or a bad connection or fuse link.
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How long should a car idle after jump start?

After getting a jump, you should leave your car running for at least 30 minutes. For more reliable results, drive it around instead of letting it idle. This should fully charge the battery so it won't die on you again.
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Will a car battery recharge itself overnight?

Since cells do not produce energy, they do not have any other mechanism to charge themselves. Simply put, no car battery, whether healthy or dead, can charge itself. It always requires an external power source to get charged.
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How often should I drive my car to keep the battery charged?

To keep your battery adequately charged, we recommend driving the vehicle once a week for at least 30 minutes, preferably at highway speeds to ensure that the battery gets the boost it needs.
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Does alternator charge battery faster while driving?

Generally, if you can keep your engine RPM up, your alternator will charge your battery at a faster rate. If you are driving on a motorway, you should be able to charge your car battery in 30 minutes. If you are driving in the city, it may take an hour or more.
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How do you keep a battery charged when not driving?

How to Keep a Car Battery Charged When Not in Use
  1. Disable Parasitic Drains. If you're planning on parking in your garage, you can disable your vehicle's security system. ...
  2. Use a Battery Maintainer. ...
  3. Disconnect the Negative Battery Cable. ...
  4. Remove the Battery Entirely.
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Why does my car battery died after sitting for a few days?

What Causes a Car Battery to Keep Dying? 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.
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How do I know if my alternator is bad?

7 Signs of a Failing Alternator
  1. Dim or Overly Bright Lights. ...
  2. Dead Battery. ...
  3. Slow or Malfunctioning Accessories. ...
  4. Trouble Starting or Frequent Stalling. ...
  5. Growling or Whining Noises. ...
  6. Smell of Burning Rubber or Wires. ...
  7. Battery Warning Light on Dash.
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What is a good alternator reading?

A good alternator should produce about 13.5 to 14.5 volts with the engine idling. If the voltage reading is low (12.5 volts or less), it indicates a charging problem but does not tell you what's causing it.
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What is normal alternator output voltage?

A good alternator should maintain battery voltage between 13.9 and 14.8 volts (14.2 is optimum). Even worst-case, with all accessories turned on, there should be at least 13 volts at the battery.
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Why is my car running at 15 volts?

Higher than 15 volts indicates a fault in the charging system's voltage regulator or related circuits. If it's substantially excessive, this can cause electrical system and/or battery damage. You mentioned your voltmeter runs at about 15 volts most of the time.
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How do you check alternator by disconnecting battery?

If you're tempted to test an alternator by disconnecting the negative battery cable, don't do it. A good alternator may indeed keep the engine running without the negative cable, but this was never a good test. In the pre-computer days, you could pull it off without damaging anything.
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