When running voltmeter should read approx. 13.8-14.2 volts
Your car should produce about 14.4 volts from the alternator when the engine is running. If it does not produce anything over 12 volts, your alternator is not charging and you need to get it repaired or replaced.
Hook up a voltmeter to the battery terminals and start the vehicle with nothing on. You should get a reading from 13.50 to 15.0 volts. Perfect setting is 14.2. A higher reading tends to overcharge the battery and a lower setting doesn't charge the battery fully. Turn a fair amount of stuff on (headlights and heater, etc.) speed the engine up and see if voltage remains between 13.5 and 15.0 volts. This shows that the alternator is keeping up with demand and alternator is working good.
It depends on the load and the voltage. In an automobile, a battery will typically have a voltage of about 12 Volts. If the engine is not running and you turn on the lights, the lights will start drawing current from the battery and the voltage will drop by a volt or so, depending on how strong a charge the battery has. An alternator will produce in the neighborhood of 15 Volts. If it is trying to push current into a system with a fully charged battery, it will only be able to push a few amps. If the voltage in the battery drops, the alternator will be able to push more amps. A completely dead battery will draw the most current (amps).
A: It all depends on the engine idle speed and cylinders. All cars at idle speed must charge the battery to 13.68 volts the RPM is a function of cinders
Check your charging system. Your alternator should put out less than 14.5 volts. Any more and it overcharges the batteries and burns out lights.
Should charge between 13 and 14.5 volts
No alternator should EVER charge at 27 volts. That's enough voltage to burn up the computer.
Either the battery is bad and won't accept a charge or the alternator is not putting a charge into the battery. Have the battery tested. You can hook up an inexpensive volt meter to the battery while the car is running. You should see from 13.5 to 14.5 volts if the alternator is working properly. If it is less than 13.5 volts then the alternator is not charging.
you need the alternator to charge the battery with no alternator when the battery drops to about 10 volts car will not run at all.
Yes. A fully charge battery will read 12.6 volts with engine not running. A 75% charged battery will read 12.4 volts. At 50% charge, it will read 12.2 volts. At a 25% charge it will read 12 volts, but that will not be enough to even start the engine in most cases and unless the alternator is bad the battery is defective. With the engine running you should read 13.5 to 15.5 volts at the battery. Any less and the alternator is defective.
I'm not sure I understand your question. An alternator will have to produce 13 volts to charge a battery at 13 volts. Most alternators are able to produce 14+ volts but the range is 13.5 to about 15.5 volts.
With the engine off check the voltage at the battery. A fully charged battery will read 12.6 volts. At 75% charge it will read 12.4 volts, 12.2 at 50% charge, and 12.0 volts at 25% charge. Now start the engine and check the voltage at the battery. It should read 13.5 to 15.5 volts if the alternator is working properly.
13.5 to 15.5 volts
From 13.5 to 15.5 Volts.
A fully charged battery will read 12.6 volts with the engine not running. It will read 12.4 at 75% charge, 12.2 at 50% charge, and 12 volts at 25% charge. With the engine running at idle you should read 13.5 to 15.5 volts. Any lower or higher and the alternator may be defective.
Should really charge it then test it with a proper battery load tester. All you can do on your own is get a multimeter and check the voltage. Without it running and having sat for a 1/2 hour or so the voltage should be approx 12-12.5 volts. Start the engine and if the alternator is good the voltage at the battery terminals should be 13-14 volts. If without the engine running the battery voltage is 12 or less this may indicate that the battery is not holding a charge. Even then the voltage should go to between 13-14 volts when engine is started showing that the alternator is working to charge the battery. If when started the battery voltage stays around 12-12.5 volts or less I would suspect the alternator. Just to double check there is the main power out terminal on the back of the alternator. With the engine running check the voltage. If 13-14 volts is present at the alternator but not the battery the circuit in between the alternator and battery is suspect. If the voltage at the alternator is the same as at the battery (12-12.5 or less) the alternator or voltage regulator may be defective.
It can put out too many volts and destroy the battery but not drain it. The alternator should put out between 13.5 to 16 volts.