Alright, long story short, I bought my 2006 F-250 powerstroke, auto, 4x4 a couple years ago with 86000 miles on it. It had just recently had a rebuilt 6g alternator installed a few months prior which began giving me problems and started searching for solutions. I started by getting new batteries and I switched to a junkyard 3g alternator which gave me trouble free service for a few years until she needed a rebuild and had to perform ficm resoldering. Had the lights flickering issue so marked it up to a bad new regulator and rebuilt it again with upgraded stator and rectifier. Still had flickering. Then started looking elsewhere for problems and found that one of the batteries was bad.had both replaced with Intersate black tops this time. Still had lights flickering issue that changed with rpm's. Then ordered an f794hd regulator but think I ended up getting an f785hd. I did the old trick of running the truck till hot and placing a wrench against the alternator pulley and sure enough was magetized. Pulled the regulator and and tightened the springs but didn't help. So this brings me up to now and what it's doing. On cold crank up after glow ups turn off, volts go up to 14 or so, confirmed with both sct x4 and multimeter. After a very short drive, they drop at idle until I hit the gas again?

 

 

And the first reading is cold after gpm is off.

 

And am being lead to believe it's the batteries but both are brand new Intersate mtp-65 with 850 cca.

 

How old are your battery and ground cables? They could be green and crystallized on the inside. Also something possibly is chafed somewhere or marginal ground connection.

 

battery and ground cables are original. Did an engine off battery current draw test and found that something (with everything off) is drawing off my batteries with the truck off?

 

Might wanna go out in the dark pop the hood and start grabbing stuff moving it around....looking for arcs and stuff. Turn on your headlights and move stuff around see if you can get them to flicker or go out

 

Which lights are flickering? The head lights or dash lights?

Voltages look good, that you reported.

 

Okay, update time after spending a nominal amount of time in awkward positions pulling fuses. Fuses #1 and #2 dropped the draw on the batteries. Fuse #1 and Fuse #2. Fuse #2 (Power point, console) is supposed to be a 20 amp and found a 10 amp in its place.

 

Lights no longer flicker bu used to be headlights, dome lights and gauge lights.

 

So, narrowed it down to either adjustable foot pedals drawing current (which have never worked for me), or the instrument cluster? Just took it out for a long drive and battery voltages according to sct x4 seem to be normal again.

 

https://www.ford-trucks.com/forums/1...c-gremlin.html

Grounds ground grounds, Read my post in this thread. I know you dont have a plow but the grounds are what Im directing you to, without retyping the whole thing.

 

I'll take a look at that next. Just went outside to check battery voltage and see how it's all going and they're reading 11.6 volts. I'm lost and just don't know what else to do if the advice in the link doesn't work?

 

A poor bond from the engine block to the body can cause the alternator voltage output to read high.

 

All grounds are cleaned, irregardless of alternator output readings, both batteries are reading 11.7. After charging one for several hours, it read 12.1. I'm gonna head to advance to get the batteries tested. What's the chances of having a brand new bad battery that eventually kills the other one?