I just put the 07+ 7/9 blade e-fans on my sub with a Nelson harness and tuned by Blackbear. I have the 145A alternator on it already but I'm wondering if it is enough? Before the fans the voltage would stay at or right around the 14v mark at idle and pretty much all the time.
With the fans, at idle when they kick on high, the voltage will eventually drop to around 12.5v or so and then come back up as I start driving. This is with the A/C on full blast front and rear. Am I needing more alternator?
I don't recall my '07 1500 Suburban doing this so I'm wondering if it had more alternator to begin with?

 

The 145A should be fine, would need to double check but i think the nnbs suvs are running them as well, whether or not they have a different voltage regulator or not is a different story..

 

As my PM on the diesel site said, 145 AMP is good to go.

 

I thought the 145 was the biggest choice for these trucks. Did you use the 145 amp from the same year vehicle..? I changed my stock 105 to a 145 when i did the e-fans on my 03 hd, i bought a harness from pcm of nc for the alternator. Which helped mine a ton, since it has an additional ground and better power wire. Also helps to have a good 3 relayed harness for the fans. Then you have low and high speed(wasn't sure what style harness you have) without the draw.

 

On the 8.1L and the Dmax's a second 145 Amp alternator was an option as well.

DEWFPO

 

I'm leaning to believe it's actually a voltage regulator issue. I know it is ECM controlled but I think mine might be on the way out. My better half reminded me that we had to have the alternator replaced about 3 years ago. She remembered having to go and buy one and then taking the core back. So the rebuilt Duralast might be going out. I'll wait till it does then put the optional 160 in it.

 

Pretty sure the 160 amp option is the one that requires the wiring kit along with it which adds a ground off the alternator directly and a fused power cable directly to the battery. The 145 is plenty unless you have some crazy load otherwise on the truck. I retrofitted 5 trucks total to e fans thus far and a new 145 amp unit worked fine. The one truck I still have I did is on year 4 now converted and it still works great. You will notice the lights dim slightly for a second only at idle when the fans come on but then the voltage comes back up immediately after the initial draw. Just sounds like an alternator problem as you are thinking.

 

It was an alternator issue after all. BUT, I direct swapped a 160A alternator in the 145s place....all problems solved plus I have extra amperage for my travel trailer and all the kids electronics, future winch install, etc....