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.
Simply so, what should voltage be at idle?
14.3 volts
Also Know, 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.
Subsequently, one may also ask, 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.
Is 14.8 volts too high?
14.8V is considered overcharging. A bad regulator over charging would most like shoot upwards of 16.0V. State of charge, temperature, age of batteries all have an effect on the charging rate. If it's cold out and you ran the batteries down some then it will be higher than normal.Where is the voltage regulator?
The voltage regulator can be mounted inside or outside of the alternator housing. If the regulator is mounted outside (common on some Ford products) there will be a wiring harness connecting it to the alternator. The voltage regulator controls the field current applied to the spinning rotor inside the alternator.Is 14.5 volts too high?
If the alternator is working well, your multi-meter should read somewhere in the vicinity of 14 volts (typically 13.8-14.2). If it is reading excessively higher than 14 volts (greater than 15 volts) it is possible that the voltage regulator on your alternator is faulty or going bad.Is 14.9 volts too high?
If it's old school, this is pretty normal, and it's time to stop charging. So, to answer your question, Yes, 15 volts is too high. Most car alternators, that normally recharge your battery after every start, and provide power while the engine is running, are normally voltage regulated to about 13.8 to 14.0 volts.Where should the battery gauge be?
How to Read a Car Battery Gauge- Look at the voltmeter on the dashboard of your vehicle. Cars operate on a 12-volt electrical system.
- Look at the voltmeter while the engine is running. Readings of 14 to 14.5 volts on the gauge when as a good sign.
How do you check an alternator with a screwdriver?
Test the alternator for magnetism. Use a metal screwdriver and place the metal end very near the bolt on the alternator pulley. It's on the front of the alternator and the alternator belt goes round the pulley. The end of the screwdriver is not drawn towards the bolt as there isn't any electrical magnetism.Does idling a car drain the battery?
Idling a car won't kill or drain your battery, unless your battery has a problem holding a charge or your car is heavily laden with high-energy consuming electrical accessories.Does revving the engine charge the battery?
But when your engine turns faster, the engine's alternator also turns faster. That way, all of the alternator's power can be directed to recharging the battery. Once the car starts, you CAN rev it up to charge the battery faster, but the best way to do that is to just drive it.At what RPM does an alternator charge?
The minimum RPM is highly dependent on the specification of alternator. But a basic alternator will produce charging current anything above 2000 rpm. We can safely say, an economy car will idle around 750 rpm, a sports car around 1250 rpm and a race car around 2000 rpm.What are the signs that your alternator is going out?
Six Alternator Warning Signs:- Dim lights. The alternator is part of the electrical system of your vehicle.
- Warning light. Most modern cars have a dashboard warning light that alerts you when the alternator is on the fritz.
- Weak or dead battery.
- Weird smells.
- Odd sounds.
- Visual cues.
