How many volts should an alternator put out at idle?
Herein, what should voltage be at idle?
One may also ask, what causes an alternator to put out low voltage? Poor ground connections are an often-overlooked cause of low charging output and alternator failure. Voltage drops on the positive side of the charging circuit can cause undercharging. Voltage drops on the negative side can cause overcharging.
Considering this, what should an alternator charge at idle?
At idle, most charging systems will produce 13.8 to 14.3 volts with no lights or accessories on (although some may charge at a slightly higher voltage depending on temperature, engine RPM, type of battery, and the battery's state of charge).
Do alternators charge at idle?
Yes, the alternator does charge the battery while the car is idling - regardless of the load on the battery. However, if your electrical use load (radio, lights, fan, etc) exceeds the amount of charge the battery is receiving from the alternator, you will end up with a discharged battery at some point.