So yesterday morning, on her way to my house to drop my granddaughter off at my house, my daughter calls me and say's her truck is acting weird. She has my old 2002 F250 and she swears it misses me, so it acts up, looking for attention.

She said while driving to my house, the radio shut off and when she looked down at the dash, all the gauges died (not the engine), and the speedo and RPM needles did the dead battery sweep, where they sweep to the max position, then back to zero. Since she was driving at the time, after they swept back to zero, they moved back up to register the proper speed and RPM output.

I meet her in the driveway with my multimeter and she pops the hood so I can check the alternator output. Sure enough, it's reading 15.8 volts, so I know the regulator is toast.

I had replaced the alternator approximately 4 months ago with an O'Reilly's lifetime warrantee Chinese special. I figured I'd get about a year out of it before it took a dump, but no such luck.

Anyway, I popped it off and got it swapped out with a new one, I just hope it didn't cook the batteries because I have no idea how long it's been overcharging. Hopefully the problem just occurred and it made itself obvious right away.

So this got me thinking. Where is the line drawn? At what point do we say, "That's too much" when it comes to alternator voltage output? Anything over 14.7? 14.9? 15.2?

Just curious what you guys thought.

Stewart

 

I draw a line at 15 volts, but 14.7 is the number when the batteries are fully charged.

 

Anything over 15 usually means the regulator is shot, the voltage set on the ford regulators is right around 14.6, the chinese knockoffs will usually fluctuate a bit, but even still over 15 is no good.

 

My son just paid Ford $525.00 to change his alternator, he was on the road. He asked is it new, they said yes. Not only is it rebuilt, it only puts out 12.4 volts max. And to make it worse, his is a 6.0L 2004.

 

If I knew mine was over 14.7, I'd be making "some adjustments". A flooded battery wants to see about 14.4 max unless it's getting an equalization charge.

I believe that (2004) six-oh's alternator is the same as a 7.3's. I bought one from eBay a number of years ago, and it is identical in every way to the one that came on my 7.3.

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