Is my alternator on the way out?

[Rick93coupe]

I'm having some charging system issues that I thought may have been because of the little Dynabatt that I have in the car. It has no reserve and if the fan or water pump are running for more than a minute, you need to charge it to get it to start. My alternator is a typical 3G alt and it has an overdrive pulley installed. When I first start the car, charging voltage is 13.8 to 14.0 volts but it quickly falls to around 13.2v. I thought it may be the battery causing the issue, so last night I installed a big wet cell battery and the car cranks a ton better than before, however I noticed voltage was 14.0v for about 2 min and it gradually started to fall off until it reached 13.2 again. Would you guys suspect the voltage regulator is bad? I had this unit rebuilt at Dayton Quality starter but I'm sure it's out of warranty even though it has very few miles on it.
I thought about switching to a stock crank pulley but revving the engine has no affect on the voltage. Thoughts?

[Rick93coupe]

I figured it out, when I wired the car, I used the Spaghetti Menders floating ground design. In their diagram, you run a ground wire to the back of both heads and a separate ground from the battery to the frame (in the back of the car). I never hooked up the ground wire to the frame, I ran the wire but it was about 6" too short. I went through and checked all my connections and realized what I had done. With a new 2gauge wire running to the frame, the voltage never drops below 13.6v.

Maybe this will help someone else out someday.

[NXcoupe]

Rick, I think it's a ground wire in the trunk. Don't ask me why, just a hunch.

[Rick93coupe]

Thanks Mike, 23 views and 1 reply other than mine. Good stuff!

[Carl]

I would rather have one knowledgable reply than a bunch BS replies... Just sayin.

[Blowpastyou]

16v with adjustable alternator... Problem solved. And it makes your power windows work AWESOME! Ask my crew last year.... lol Charlies son about lost his fingers a few times.

[86gt40]

Heck when I saw 13.6 I thought you were out of the woods