Cs144 alternator install question

[MEMO43]

Ok as the title says
I have a cs144 alternator installed in my rig.
it's an 85 chevy k20 with a l31 (roller cam from a 98 1500). Summit Racing max efi, dual windsor fans, relay mods to both low/high headlights. I have allstock gauges with no dummy lights, just the basic full sweep style.
I 'm running the serpentine system with reverse flow water pump and currently have a cs144 (140 amp) alternator. Brand new, along with an 850 CCA AGM battery.
I have the adapter plug with the resistor in-place.
My dilemma is that at the gauge I'm only showing 13.5 . At the battery I'm showing 14.6 same as the alternator batt stud as well as the junction block. I've verified good grounds and solid connections etc etc. I'm using 4 gauge battery wires for both pos and negative, to include battery to frame. for the engine to frame I'm using braided ground straps total of 2. everything else is 10 gauge.
My headlights dim at night when the electric fans kick on, and voltage readings drop.
Do I really need the resistor at the adapter plug since I don't have dummy lights. I'm thinking that is what is keeping my from getting full voltage output from the alternator, I have another adapter plug without the resistor ready to swap out but wanted to make sure I'm not going to fry anything.
Thanks in advance

 

[K85 Octane]

That’s a head scratcher for me. Love to see why the drop is so much. I’m sure that gauge is going to read lower but that seems excessive.

I’m running a DR44, or AR44…something like that. It needs the computer to run at 14.7, or a regulator rework. I just leave it. Runs at 13.5. With every light, fan, speaker, etc etc going it drops to 13.2. I’m good with that.

The resister could just be a light bulb no? Or a light inside the cab that stays keyed on? Following

 

[Blue85]

Which version of the alternator do you have? (which terminals are being used?). Are you using the external sense wire and if so, where is it connected?

https://ck5.com/forums/threads/alternator-voltage-fluctuation.340096/#post-4079031

Also, somebody has to ask how your fans and headlights are wired. It's possible the voltage at the alt is staying the same, but you're just seeing the normal results of the factory headlight wiring.

 

[dyeager535]

And have you verified voltage at the gauge? You could check at the IP connector for that, or whichever fuse feeds that circuit. It's possible I suppose, for the gauge to be wrong as well as a poor connection.

Voltage at the panel?

Pretty sure you need some sort of resistor or they won't start charging. That resistor isn't on the output of the alternator, so it's not "blocking" current flow.

 

[MEMO43]

Thank all for the prompt responses
As for the gauge readings I'm using both the stock gauge as well as the digital readout from the efi system. That way I can eliminate a bad reading.
As for the Fans and headlight wiring I'm running 30 amp relays for each.
The sense wire I have running to the factory junction block
I build a relay bank system upfront just for them.
I'm using 10 gauge wire for the battery junction block.
1 relay powers a fuse panel the is triggered by key one.
I'll get some more pictures up later today.
I've attached some pictures that I have on my phone showing the plug and alternator terminals.

 

[frankin5]

Correct me if wrong, the sense wire is to be connected to a key on source of power. The junction block is a constant power source.

 

[6872xtc]

If you have 14.6 at the charge stud and junction block, then the truck wiring is the problem. I wouldn't want higher voltage output from the alternator myself, the battery won't like more long term and some things don't like more than 15V.

Having dim headlights, at idle with the fans on would tell me that maybe the alternator doesn't have enough rpm. That would show as low voltage at the alternator charge stud and elsewhere.

I would look for a problem in the headlight circuit and possibly the fuse block junction at the firewall for the difference in voltage. I would think that you could gain some on the voltage drop.

 

[MEMO43]

Thanks all for the response's I will see if I can find or trouble shoot were I'm losing voltage. Anyone have a pic original alternator wiring. As well as fuse box.
I think I may have discovered my issue.
I removed a "Shunt" from my fuse box, not knowing what it does or better yet how to find a replacement.

 

[dyeager535]

Shunts are used to connect two of the power feed strips inside the panel together. Pulling a shunt out breaks that connection, so nothing on the other leg gets power.

It's a solid connection, in a pinch you could put a very large fuse in and see if it holds, like a 40A.

No reason to be messing around down that low on the panel, the upper portion has more extra feed spots than most people need. However either way you are bypassing fuse protection so keep that in mind.