What should the voltage be with alternator running?
around 14 volts
Output voltage should be around 14 volts (13.8 to 14.5 depending upon the application) with the engine running. If you check the voltage at the battery under the same parameters, you should not have more than a half volt drop between your result at the alternator and the result at the battery.
What causes alternator voltage to fluctuate?
When the battery’s state of charge is low, the voltage is raised slightly to quickly put the charge back in. When the state of charge is high, the voltage is lowered slightly to prevent overcharging. If the vehicle has a voltmeter gauge, you may see the voltage move up or down. This is normal.
Can a bad battery cause voltage fluctuations?
A battery that is on it’s way out(faulty cell) or bad connection could cause the fluctuations you see. A simple problem of loose wires and connections can cause your battery voltage to fluctuate. You may think it is flat, charge it and afterwards voltage can go as high as 15V or 16V.
What should the voltage be on an alternator?
Alternator Testing: What Is The Correct Voltage? For some alternators, it’s normal to see as low as 13 volts. For some, a constant 13.6 volts is an indication of a problem.
What does it mean when battery and alternator don’t match?
Also the voltage at the battery and the voltage at the alternator should be within 0.5v of each other. 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 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 to do if your alternator has bad ground?
Place the red lead on the positive battery terminal (if possible dig it into the battery post, not the terminal). Place the black lead on the bad post of the alternator. Same thing as above, if the voltage is above 0.5v then examine the positive cabling for problems.