How many volts should an alternator put out at idle?
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. Click to see full answer
When does an alternator need to be charged?
Alternator output is on demand when there are loads detected or the battery needs to be charged. Depending on ambient temperature, charging voltage varies.
What should the voltage be on a bat alternator?
Measure the voltage across the battery and the big bat alternator terminal to alternator case. There are two things that you are looking for. The charging voltage should be between 13.9v to 14.4v. Also the voltage at the battery and the voltage at the alternator should be within 0.5v of each other.
Can a dead voltage regulator be replaced in an alternator?
At least a dead voltage regulator in the alternator. The voltage regulator can be easily replaced without removing the alternator most of the time, and usually is cheap so worth a try. Nevertheless, you should definitely clean those connectors and terminals every now and then. – galingong Feb 15 ’17 at 9:25
Alternator output is on demand when there are loads detected or the battery needs to be charged. Depending on ambient temperature, charging voltage varies.
What’s the correct voltage for a fully charged battery?
The rule of thumb that states 12.6 volts equals a fully charged battery and 12.2 volts means it is 25 percent charged, is starting to change with some modern batteries and charging systems. If there is a dead or weak cell, normal charging voltage can’t be achieved on a battery with a bad cell.
What does 12.6 volts mean on a battery?
Also, most modules on a vehicle will set a code if low system voltage is detected. The rule of thumb that states 12.6 volts equals a fully charged battery and 12.2 volts means it is 25 percent charged, is starting to change with some modern batteries and charging systems.
What causes an alternator to output low volts?
If the voltage at the battery and alternator don’t match. For example the battery reads 12v and alternator reads 14v. This means that there is an issue with wiring. While applying the same conditions as above.
What happens to the battery when the engine is idle?
At reasonable to maximum engine speeds, typically from 1500 RPM to redline with heavy loads, and from idle all the way to red line with light electrical accessory loads, the battery just goes along for the ride. It really doesn’t do anything, except wait for the alternator to fall below operating speeds.
What should the battery voltage be at cruising rpm?
If voltage is over 14.2 under maximum loads when at cruising RPM, buying a bigger alternator or a new alternator is a waste of time and money. Turn the motor off with no load (headlights, etc. all OFF) and read the battery voltage. With the engine just shut off, the battery voltage should be 13.2 volts to 13.8 volts.
What should a low idle voltage be for an alternator?
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 the voltage be when the engine is idling?
When I measure voltage at the battery terminals while engine is idling, it’s a pretty low 12.5v~ or so, when cooling/HVAC fans come on it can go below 12V completely. Revving the engine can top me out at 13V.
What would make my voltage drop from 14 to 11?
First I had the battery light flash in message center and voltage was at 14.7 and took to AutoZone and replaced battery. Light was off for one day then back on. Then next day voltage was at 14.7 and stopped and started back up and I noticed the volt meter went to 11 and stayed there.
What’s the normal charge voltage for an alternator?
, An electron pushing physicist Pretty much. Normal charging voltage can vary from 13.5 to 14.5 volts or even higher depending on the battery’s state of charge, temperature and electrical load on the alternator [1] A car alternator gives charge to the battery(12 volts) with14.5 volts. Yes!
An alternator should put out between 13.5 and 15 volts of power. The alternator should be tested with the engine idling and electrical accessories, such as the radio and headlights, turned off.
What are the symptoms of a bad alternator?
BAD ALTERNATOR SYMPTOMS: 1 Dim lights. The failing alternator symptom most drivers recognize is dim or flickering lights. 2 Service engine light. Another obvious sign is the one your vehicle tries to tell you. 3 Odd noises. 4 Electrical issues. 5 Engine stalling. 6 Dead battery. …
What causes an alternator to go over base voltage?
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.
Why does my alternator make noise when I Turn on the engine?
A loose alternator belt may be the culprit. If the serpentine belt is loose, it often results in various noises coming from your engine. With a loose belt, it doesn’t sit right up against any pullies that are rotating it so noise may occur from the friction.
What causes an alternator to get really hot?
High voltage, bad diode, improper alt fan, bad bearing , defective heat sink ,high voltage drop accross alt power wire or ground wire . A few places to check alternator fan, now why didn’t I think of that?
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.
What should the voltage drop be on a Toyota alternator?
Photo 3: This alternator B+ to battery B+ voltage drop test indicates slightly less than 0.100 volts, which is well within Toyota’s 0
Measure the voltage across the battery and the big bat alternator terminal to alternator case. There are two things that you are looking for. The charging voltage should be between 13.9v to 14.4v. Also the voltage at the battery and the voltage at the alternator should be within 0.5v of each other.
Most alternators that are charging properly should produce a voltage of about 13.8 to 14.2 volts at idle with the lights and accessories off.
How many volts should an alternator be charging?
To fully charge in reasonable times, alternator output must be 14.2 V to 14.5 V as measured right across the battery posts. Above 14.5 volts charging voltage, batteries have a greatly increased tendency to release excessive acidic vapors, hydrogen gas, and to corrode things around the battery.
Can a bad alternator leave a Toyota RAV4 without power?
A bad alternator can leave your Toyota Rav4 without power and unable to move. Alternators don’t always go bad in the exact same way. We’ll cover the symptoms of when an alternator goes bad, and how to diagnose a bad one (which is really pretty easy).
What should the alternator voltage be at rest?
Here’s why: The battery’s voltage, at rest, is 12.5 Volts. So one of the best indicators that the alternator is charging it, is verifying that battery voltage should be at 2 Volts over battery voltage (at rest) when the engine is running.
How many volts does it take to charge a Toyota battery?
For example, at 70° F, the voltage regulator charges the battery at approximately 14.2 volts. As underhood or ambient temperatures increase, the charging voltage is reduced to about 13.8 volts or less to prevent boiling the water from the battery electrolyte.