Quick Answer

Question: Why is my battery 17 volts?

It may be that the regulator is packing up and the alternator is going to max. unregulated output because of a bad battery output voltage (alternator input) connection between the battery and the alternator.

What voltage is too high for a 12V battery?

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 12-volt battery test at?

Fully charged automotive batteries should measure at 12.6 volts or above. When the engine is running, this measurement should be 13.7 to 14.7 volts. If you don’t have a multimeter to tell you the voltage of your battery, you can do a test of your electrical system by starting the car and turning on the headlights.

At what voltage should a 12V battery be replaced?

The resting voltage should ideally be no lower than 12.6V. Bear in mind that when a battery goes down to 12.2V it’s actually only 50% charged, and below 12V it’s classed as discharged.

Is 17 volts too much for alternator?

17V is too high for any 12 V battery. 17 volts is just about max unregulated output on a 12 volt alternator so I would suspect that the voltage regulator is defective or somehow not working correctly. To put things in less dramatic terms.

What happens if the battery voltage is too high?

When your battery voltage becomes too high, you can fry your vehicle’s system. Car computer systems are directly affected by the battery. With the high voltage causing inconsistent charges to the entire car, the computer system can be damaged.

What should a 12-volt battery read on a multimeter?

Measure and Analyze

When the probes touch the terminals while the car is off and the battery is resting, the multimeter display should show a reading of 12.2 to 12.6 volts (full charge). This voltage range means the battery is in good condition for starting the vehicle.

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.

What should a battery read when car is running?

When we take a closer look, we see car battery voltage can range anywhere from 12.6 to 14.4.

  • With the engine off, the fully charged car battery voltage will measure 12.6 volts. This is known as “resting voltage.”
  • When the engine is running, battery voltage will typically rise to 13.5 to 14.5 volts.

How can I tell if my 12V battery is bad?

If your battery is:

  1. Reading 0 volts, chances are the battery experienced a short circuit.
  2. Cannot reach higher than 10.5 volts when being charged, then the battery has a dead cell.
  3. Fully charged (according to the battery charger) but the voltage is 12.4 or less, the battery is sulfated.

What voltage is too low for car battery?

What voltage is too low for a car battery? A car battery is dead if its voltage is anything between 11.75 and 11.89 volts. Any reading between that range means that the battery is no longer functioning and a car owner should consider a replacement.

How do you read battery results?

Battery voltage readings are as follows:

  1. 12.66 volts = 100% charged.
  2. 12.45 volts = 75% charged.
  3. 12.24 volts = 50% charged.
  4. 12.06 volts = 25% charged.
  5. 11.89 volts = 0% charged.

How can you tell if car battery needs replacing?

How to Know When it is Time to Replace Your Car Battery

  1. 4 Signs It Is Almost Time For a New Battery.
  2. 1) Your Battery Struggles to Combat Seasonal Challenges.
  3. 2) Your Car Has Been Sitting For Too Long.
  4. 3) Your Vehicle Struggles When Starting.
  5. 4) Your Battery Is Older and Triggers a Dashboard Light.

How do I know if car battery needs replacing?

7 signs your car battery is dying

  1. A slow starting engine. Over time, the components inside your battery will wear out and become less effective.
  2. Dim lights and electrical issues.
  3. The check engine light is on.
  4. Bad smell.
  5. Corroded connectors.
  6. A misshapen battery case.
  7. Old battery.

What should a fully charged 12v battery be?

The standard automotive battery in today’s vehicles is a 12-volt battery. Each battery has six cells, each with 2.1 volts at full charge. A car battery is considered fully charged at 12.6 volts or higher.

What are the symptoms of an overcharging alternator?

Symptoms of Your Car Alternator Overcharging:

  • Car Battery Voltage Gauge Reading is High. You notice a high voltage reading on your cars vehicle’s dashboard.
  • Car Battery Gets Hot When Charging.
  • Your Headlights Burn Out Quickly.
  • Your Car Battery is Bulging on Sides.

Why is my alternator putting out many volts?

If you are getting more than 2 volts above base voltage, most likely your alternator is over-charging the battery or the battery is faulty. Other potential problems are a faulty voltage regulator or a problem in the charging system wiring.

Can an alternator overcharge the battery?

Overcharging of the battery by a defective or malfunctioning alternator will result in the battery reaching an overcharged state. When overcharged, the plates inside the battery shed material and lose their capacity to hold electricity.

How do I know if my car battery is overcharging?

When the vehicle is started, without the introduction of a load (the lights or air conditioner), the volts will usually rise to an average of 14 volts. If the multimeter reads at more than 14.8 volts, then this can be considered as overcharging.

What is the correct voltage for an alternator?

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.

Is 14.8 V too high for a car battery?

For a car with a 12V engine, the normal value before starting is between 12.2V and 12.8V, and it should not exceed 14.8V after starting.

How do I test 12 volts with a multimeter?

12V Guide: How to use multimeters

How do I test a 12-volt with a multimeter?

You have to set the multimeter to a range that it can measure. For example, 2V measures voltages up to 2 volts, and 20V measures voltages up to 20 volts. So if you’ve measuring a 12V battery, use the 20V setting.

What voltage is too low for a 12-volt deep cycle battery?

Rule of thumb, don’t go below 50% – for best battery life on a 12V battery don’t go below 70%.

What should voltage be at idle?

Additionally, once the engine is running, the battery should be receiving a charge from the alternator. Because of this, the multimeter should read between 13.8 and 14.5 volts when the engine is at idle.

Is 14.5 volts good for a car battery?

If the voltmeter reads between 14-15 volts then the battery is normal. But if the battery reads over 15 volts or less than 13 volts, then there might be a problem with the voltage regulator, the wiring or the alternator.

Is 15 volts too high?

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.

Is 12 volts enough to start a car?

The modern standard worldwide is 12V, but this parameter is changeable: The normal voltage needed to start the car begins from 12.6 volts. At the time of exploitation, this parameter is between 13.7 to 14.7 volts.