'93 Ranger charging system issues

[4.6StangRage]

First of all My alternator charges, but it is working improperly. One day I noticed my battery idiot light and my voltage meter moving from normal to low volts. I drove it about 14 miles total and had no driving issues what so ever. I realized that during initial idle it was not charging but when in higher RPMs (3500-3600+ RPMs) it will charge. Finding out this information I decided to park the truck for a few days. After the few days I popped open the hood, input my meter on the battery and read a healthy 12.56 volts. I cranked it over and it read 12.06 volts until i pressed the throttle and made it charge at 3500-3600 RPMs. At first the charging was brief and then I revved the engine up a second and third time. It charged for about 20 seconds at 14.6 volts. I checked the tension on my belts and found nothing wrong. What could be wrong with my charging system. My suspect is some component in the alternator, but I am not sure. Voltage regulator maybe? what do you guys think?

 

[Bryan22]

ya, sounds like the regulator isn't working properly. but i would try cleaning all connections and battery cables/terminals before going after a new alternator.

 

[scotts90ranger]

a new voltage regulator is usually only like $15, brushes around $5, not all that hard to put in if you have the right torx driver, a tip, there's a hole in the regulator to stick a piece of wire in to hold the brushes while you put it in, makes it an easy job.

 

[BRUTUS_T_HOG]

try wiggling the wires at the back of the alternator.

 

[red85]

Sounds like the brushes in the alternator are worn out. Just buy a rebuild kit and rebuild the alternator. They're usually about 25 bucks and the kits come with new bearings too.

 

[4.6StangRage]

thanks guys,

I like the rebuild idea and I am thinking of doing it! It is the original alternator and I would like to keep it original if possible. I had the alternator tested and it failed, so it is definitely needing to be repaired. thanks for the info!