Alternator voltage

[Shallow Draft]

I just noticed my voltage show between 13.3 and 13.6. Is this normal?

 

Also when you blow a trailer tire and it tears off the wires as it shreds be sure to check that the two wires don't touch each other. Otherwise you will not have trailer brakes going through Vegas in rush hour.

Very thankfull for lots of truck brakes.

[Mark and Dale Bruss]

Yes, 13.3-13.6 is normal

[Yarome]

I just noticed my voltage show between 13.3 and 13.6. Is this normal?

 

At the alternator or at the battery? At the battery that's probably considered "normal", but I would consider it a touch low. I would like to see 13.8-14.2, but anything between 13.5-14.5 would be "acceptable". If you're getting 13.3-13.6 at the alternator.. it's getting time for a trade out.

[Shallow Draft]

Thanks for the help. Stress relief! !!

[Dollytrolley]

 

At the alternator or at the battery? At the battery that's probably considered "normal", but I would consider it a touch low. I would like to see 13.8-14.2, but anything between 13.5-14.5 would be "acceptable". If you're getting 13.3-13.6 at the alternator.. it's getting time for a trade out.

 

Huston, my "heavy-electrical dictator" used to give me hell for complaining about charging voltage.......

 

I would say "Huston, this darn alternator is only putting out this much charge"........Huston would respond "Forget the charge rate....what was the temperature of the alternator??"

 

Many alternators "performance" degrades sharply as the alternator temp rises.....some become pretty pathetic units as the come up to operating temp.

 

As a general rule you see that largest body alternators on stationary equipment that tend to have hot engine compartments.

 

Many truck manufactures tend to size alternators small hoping that the truck drives fast enough to keep the airflow somewhat cool on the small body alternators........often a poor bet, but it keeps cost down...and charge rates down when hot...

 

Drive on........(Keep cool and well .....charged)

[Alie&Jim's Carrilite]

On most vehicles the voltage is read at the starter, I assume this is correct on our trucks as well. If the connections are getting corroded, or if a cable end has split allowing corrosion inside the wire jacket, it will affect the voltage.

[MrSeas]

If you have the time..... charge up the batteries using a battery charger and make sure your batteries will charge and maintain

voltage. Run the truck and check for proper voltage. Sometimes the alternator will get " overwhelmed" when your batteries are too low voltage wise. Might save you an alternator change.

[Dirt]

replaced mine a while back and the new one is about a volt higher...13.8 is normal old was weak and i though so....food for though......FYI....

[NoDirectionHome]

Unless you're using a sharp pointed probe on the alternator output lug you're reading through a dirty window. As with most issues on these old trucks, CLEAN the TERMINALS first, then let us know what you're seeing.

[Mark and Dale Bruss]

I once had a poor terminal connecting to the alternator. With a digital meter I read 14 volts at the starter and only 13 volts at the battery. Illogical until you consider analog signal voltage (sine wave). Replaced the terminal and the voltage became constant at starter and battery,

 

The dash data display shows the voltage at the batteries.