I have a question. I'm not having any problems but noticed today I am running 13.2 volts while idling and running down the road. Now I have upgraded the big 3 to 0 gauge, have a 230 amp alternator and yellow top battery. I also checked voltage at the alternator and it is 13.2 as well.

If I turn all my auxiliary lights on it drops to ~12.9-13.1 which includes 4 - 6" lights, 30" lightbar, 9 rock lights. After shutting them down it climbs back to 13.5-13.6. If I run the winch with no load it does the same 12.9-13.1 then climbs back up to 13.5-13.6 before balancing back out at 13.2.

Now when I first installed everything it tested out at 14.3, Is it possible the system keeps up without issue or is the alternator going out?

Don't have any dimming issues, starting issues even after sitting for weeks, battery stays at 12.6 while truck is off.

 

I believe it is a ground issue. I tested it this morning and had 14.1 volts but checked the negative to the alternator case and got 0.3. So I will trace those out later and find the culprit.

 

I would definately think it's a ground issue. When mine was bone stock, changing my broken negative terminal out moved my voltage from 13.1 to 13.8 without even changing wire size. Good luck.

 

Yeah I believe so now. It should be lower that 0.1 testing the negative to the alternator.

 

Couldn't figure out why I was still getting negative resistance at the case only. The case was powder coated so I thought maybe it was causing the problem so I unbolted it and sanded the paint off the mounting points. Nope still getting resistance.

Well there is a strip on the case down the middle that wasn't painted and that where I was taking my reading cause I wasn't getting a reading on the painted portion to the right of the strip. I then checked the painted portion to the left of the strip and had resistance. At that point it dawned on me that I was getting the resistance from the case. Tightened up the bolts that hold the case together and fixed.

Went thru everything just to need to tighten a little bolt on top of the case lol.

 

Glad you got it figured out!