Dodge RamCharger Central banner
1 - 6 of 6 Posts
G

·
Discussion Starter · #1 ·
Hey Everybody, I am sure this topic has been beat to death, but I was unsuccessful in pulling anything off of the site with a search. I have a newly rebuilt alternator in my truck and the thing is running sweet now. However, while driving it around yesterday, I noticed that the ammeter in the dash was indicating that the alternator was overcharging. The battery is new; it was severly drained prior to the alternator being rebuilt. What is going on here?

Thanks!
 

·
Registered
Joined
·
6,480 Posts
Check the voltage regulator first. They aren't that expensive at autozone. And you said you were able to tell it was overcharging through the stock ampmeter? My stock ampmeter barely moves at all on either side of the center mark.
 

·
Premium Member
Joined
·
17,219 Posts
the stock voltmeter will usually jump to the positive side when you first start the truck but then will usually settle back to the middle in just a few minutes, if the battery was severely drained it might take as much as a half hour of driving/running to settle back to the center.

if it takes longer than this, or if you have a higher output alternator than stock, you may have to go to either an aftermarket voltmeter/ammeter, or check the VR

eric

ps: is it an ammeter (shows amps usually 8 to 18) or the stock voltmeter (shows positive/negative?)
 

·
Premium Member
Joined
·
4,879 Posts
Probably just the extra amperage to charge the battery back up showing on the ammeter, BUT:

To be on the safe side, you should check to see if your alt is being full-fielded by a short in the wiring. To do this, find the green* wire coming from the voltage regulator. This wire runs directly to your alternator, and nowhere else. If this wire has rubbed through the insulation anywhere between the alt and the VR, it can ground out and full-field the alt (tells the alt to put out max amperage).

*I am reasonable sure the wire is green. I am not sure if the wiring changed colors from '87 to '88. I'm sure Chump will jump on this and correct me if I am mistaken.

-SM
 

·
Moderator
Joined
·
29,451 Posts
Slanted_Mind said:
Probably just the extra amperage to charge the battery back up showing on the ammeter, BUT:

-SM
I believe Slanted is right.
Also, an ammeter won't show an overcharge condition, it is just showing current flow. Too high of voltage coming from the alternator causes an overcharge condition, not high amperage. If the battery is drawing a lot of amps, it either is in need of those amps (like the drained battery you described) or the battery is shorted internally.
Before you start chasing wires, just check the voltage at the battery while the engine is running. If it is somewhere between 13.6 and 14.8 (depending on ambient temp), your good to go.
 
G

·
Discussion Starter · #6 ·
intenseimages said:
the stock voltmeter will usually jump to the positive side when you first start the truck but then will usually settle back to the middle in just a few minutes, if the battery was severely drained it might take as much as a half hour of driving/running to settle back to the center.

if it takes longer than this, or if you have a higher output alternator than stock, you may have to go to either an aftermarket voltmeter/ammeter, or check the VR

eric

ps: is it an ammeter (shows amps usually 8 to 18) or the stock voltmeter (shows positive/negative?)
sasha is equipped with ammeter; however, instead of the 8 and 18, an "D" ( i assume for discharging) and an "C" (for charging) are located on either side of the guage.

I have also learned that the voltage is regulated by the ECU.

I believe it was the fact that the battery was dead as the reason for the ammeter "pointing" towards the "C" side of the guage. I went and drove it yesterday (about 30 mins) and by the time I made it back into town, the needle was pointing just a little bit to the right of the center mark.

thanks for the info guys!
 
1 - 6 of 6 Posts
Top