What should my alternator be charging at

If the replacement alternator does not come with a new pulley, be sure to install the correct pulley with it. If not, the replacement alternator can fail sooner than expected.

Many so-called alternator problems turn out to be nothing more than a bad connection at the alternator or a bad wiring harness. Advertisement If You See This.

If you see a modern vehicle that measures the life or temperature of the battery, it is bad practice to use the positive and negative battery terminals to power aftermarket accessories.

The extra connections can cause the battery to incorrectly report the state of discharge, despite a normal battery condition. Electronic: Multi-Spark Ignition Systems. Digital Edition. Contact Us. Shop Owner. Special Topics Webinars Video Podcasts.

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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. Do alternators work at idle?

Most modern vehicles control the alternators field coil and idle RPM to optimize the alternator's output. Most economy vehicle ECU minimize fuel consumption and thus alternator output at idle providing just what's needed to keep the vehicle running while stopped with minimal charging if any. 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. How can you check an alternator? Alternator test with a voltmeter If it's in the range, it's good.

Connect the meter leads to the battery terminals and look for That means the alternator is pumping out the juice. Will revving engine charge battery? The battery will charge faster if you rev the engine faster. A battery will consume noticeable engine power only when the battery is low on charge and the missing charge is being replenished.

A battery, when charged, is really just an electrical storage tank. NEVER pull the battery cable to check the alternator.

This very crude test method was marginally OK when we had vacuum tube car radios and point-type ignitions, but it is a very bad idea now. The battery stabilizes the electrical system and loads the alternator, preventing high peak voltages or voltage surges as the alternator adjusts magnetic flux to produce the same average voltage at different current demands.

If you rev the engine up and pull a battery cable, the alternator voltage can spike up to volts or higher before the alternator flux dies off enough to bring voltage back down to 14 volts or so. This can kill the car's computer and other expensive electrical components. I've seen headlights blow out when a guy opened a battery switch while an engine was revved up.

If you hear anyone telling someone this is a way to check an alternator in a modern vehicle, stop them! To charge the battery, the alternator voltage output has to exceed a minimum charging voltage. This minimum charging voltage is A single lead-acid cell starts to charge at anything over 2. Since a 12 volt battery has six cells, any 12 volt lead-acid battery needs at least This voltage will be enough to fully charge or maintain the battery on a trickle charge, but charging time will be very long at To fully charge in reasonable times, alternator output must be Above The battery terminal charging voltage must be less than Charging voltages over In this case the battery charging voltage is The battery above will slightly gas, but not enough to be harmful, and the battery will get a quick full charge recovery after starting.

Less than Much less than When running at a normal slow cruising engine RPM, the voltage across the battery terminals should stay over If this system was in a restored GT coupe, I would probably change the regulator to reduce maximum alternator voltage. This would prevent deterioration of metal around the battery from excessive charging vapors.

It's OK in my daily driver as long as I watch the battery for purged acid deposits. If you measure battery voltage and it is anywhere over If voltage is over Turn the motor off with no load headlights, etc. 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.

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. 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.

The minimum RPM is highly dependent on the specification of alternator. But a basic alternator will produce charging current anything above rpm. We can safely say, an economy car will idle around rpm , a sports car around rpm and a race car around rpm.

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. The voltage should read a minimum of 13 volts. Stress test the alternator - Place a load on the alternator by turning on the headlights, the radio and the air conditioning.