Hi, my 2009 Escape, 3.0, had a random battery light on last night. I checked this morning and the light is out, no codes, and the running battery voltage is 15.8 and up to 16.8 volts.
Does the alternator have a voltage regulator? Or is the voltage controlled by the PCM?
Any thing to check, besides clean and tight connections?
Thanks Artie

 

What's the temperature in Indiana? I think that's where your profile says you're at. 14.5 to 15 volts after starting in subzero temps would be what you want to see.

Your numbers are way too high. Back up a second. What are you using for measurement? Just about any powered DVM will become wildly inaccurate with a weak internal battery. Just Sayin'.

But, since you just had a battery light, better get it checked out and sure sounds like bad regulator, loose connections, etc. Still, pull the battery first and charge it up and test, alternator sounds like it's going south though.

As you know the problem is a bad battery can damage a charging system and a defective alternator can ruin the battery. Breaking the cycle of abuse is the idea.

 

The 2010 Wiring Diagrams book shows that the alternator has an internal regulator. The PCM can monitor the alternator output via two leads to it from the regulator.

If you look at online parts pics of the alt, you can see a three-pin connector sticking out the side near the rear of the alt. That should be the regulator.

Whether the internal regulator can be replaced like many Ford alts from the outside, I don't know. A quick check of Rockauto.com and O'Reilly did not turn up a voltage regulator as a replacement part.

 

Hi, wanted to post a follow up about the overcharging alternator. Appears the voltage regulator is internal.