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How many amps should my alternator be at idle?
Most late model alternators produce 120 to 155 amps or more. Current output increases with engine speed, from around 20 to 50 amps at idle up to the unit’s maximum output at 2,500 RPM or higher (refer to a service manual for the exact charging output specifications for your vehicle).
Can a car alternator produce AC current?
An alternator is so named because it produces alternating electrical current. Thus, the 12-volt AC output from an alternator can be transformed into 120 volt-AC current.
Does alternator work on idle?
The good news is that yes your car battery will charge when idling. Your alternator produces electricity when your car’s engine is running so as long as your car engine is on and your alternator is working properly your car battery will be charged.
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 should the voltage be on an alternator?
Put the black multimeter probe on the negative battery terminal (if possible dig it into the battery post, not the terminal). Put the red probe on the alternator case. Your looking for the voltage to be below about 0.5v.
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.
How can I tell if my alternator has bad ground?
Preform the same test with the positive side. 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.