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Alternator dying?

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Old Dec 17, 2023 | 10:35 PM
  #31  
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Ok!

New alt on. Voltage is still a tad low, but after an loser lap, the batteries are showing 12.7 standing with the truck off.

Truck was already warm for this trip.

batteries were 12.1 standing starting my loser lap.


Crusing the highway. It was up to 13.8 to 13.9.


Idle after the loser lap.

Still seems kinda low over all, ill keep an eye on it. I wanna see that 14 volts...

Could the field wire be bad?

Im going to do more of the ground lugs too after christmas.
 
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Old Dec 17, 2023 | 10:45 PM
  #32  
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From: Bottom Of Pikes Peak
what alt did you end up going with?
 
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Old Dec 18, 2023 | 12:20 AM
  #33  
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Originally Posted by INFRNL
what alt did you end up going with?
The bosch 135a from the 6 liter.
 
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Old Dec 18, 2023 | 01:51 AM
  #34  
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once you get the batteries Equalized, on a long enough road trip, you will see 14.4ish and then the regulator will taper it back down to 13.6 for a while, and then 13.3 where it will pretty much stay
 
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Old Dec 18, 2023 | 08:55 AM
  #35  
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Those are the numbers I started seeing after I mounted my PCM properly
 
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Old Dec 18, 2023 | 10:24 AM
  #36  
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Tme to start poking around with a multi-meter checking voltages. Check voltage at the battery terminals and at the alternator B+ lug and see what you find.
 
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Old Dec 18, 2023 | 06:06 PM
  #37  
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So just an update.

Saw 14.0v on the way home today (short drive).

Im going on a longer drive tonight so ill keep an eye on it.
 
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Old Dec 18, 2023 | 08:49 PM
  #38  
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Ok.

Now im trippin.

Its like the alt is in some failsafe mode and isnt really regulating voltage. I did a drive on the highway for an hour, and it didnt really come down to 13.2 nor did it really go above 14. Mostly hovers at 13.8ish. Didnt really vary too much.

Ill go through all the connections again. Take some measurements too.

There a wiring diagram of the plug? Maybe a connection died there. One of the wires does look like it might be pinched a bit at the connector.

Am i being dumb?




Winding down after the hour trip.


Idle after the hour trip. Just parked before shutting down. Seems good there. Never seen it so high at idle.

 
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Old Dec 18, 2023 | 09:17 PM
  #39  
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Here is the electrical diagram.

https://charm.li/Ford%20Truck/2001/E...ging%20System/

Drive it some more. It's OK to charge continuously around 14v. My voltage did not drop into the the 13s until I drove for several hours in daylight Your battery state/health will also affect charge voltage along with the electrical load.

 
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Old Dec 18, 2023 | 11:47 PM
  #40  
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13.8 is just fine, quit worrying about it.
that is right at Equalization, long term battery storage voltage.

the batteries are fully charged and all is well.
some charts for you to peruse.

NOTE: in the 1st chart, your batteries are at "Float Voltage", right where they should be.










this last chart, needs some Long Study Time, to understand what it is showing you.
Temperature vs Charge vs Short "go to work and back home trips"


 
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Old Dec 18, 2023 | 11:51 PM
  #41  
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my non-stock MechMan self regulating Alternator runs in the 14.4 all day long territory, like from Atlanta, GA to Oologah, OK and it stayed at 14.4 all the way.

does that hurt the batteries? no, they at are 'boost' voltage...
 
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Old Dec 19, 2023 | 07:24 PM
  #42  
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Saw 14.2 on my short drive into work. I think i will say its fixed.
 
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