Alright, so I've done some searching and can't find any posts similar to what I'm dealing with. The closest I can find on google is something referring to the battery current sensor. Aparrently its only on 2005+ Tahoes though, but it senses draw and adjusts alternator charging output accordingly. Mine is a 2000, and when I went through my Big 3, I saw no such sensor as expected.

The issue I'm having is a lot more noticeable now that I have a Stinger volt gauge in the dash (Installed same time as new HO Alt, 9/11/19) When I start up, I'm at around 14-14.3v.. after warmed up, 13.9v is consistent. Now... I've notice multiple times that when I am coming to a stop, or slowing down to make a turn, I see a large drop to high 11's to mid 12's.. but straight back up again to 13.9v after fully stopped or out of the turn I was making. 

Happens regardless of draw (Lights on/off, heat/ac on/off, volume high/low)

I would like to assume this has something to do with my main battery, seeing as how its a standard wet cell and has some age to it. I plan on swapping for an NSB34/78 in the near future when the wallet isn't empty. I just want to make sure I'm not missing something stupid or something that could be addressed in the mean time until I get a new cell up front. 

Also for the record, while sitting still at idle, or at cruising speed, full tilt on the music yields less than .1v drop if any, no dimming either.

2000 Tahoe 5.3

Big 3 (4 soon) in 2/0

255a Alt

Standard Group 34 wet batt

Not sure what other info is needed, but I can get as specific as you need... Any ideas? 

I'm going to bet it a power steering issue causing strain on the pump which causes excessive parasitic drag.  This could cause belt slippage, or tensioner issues which means the alt struggles while turning.  Come out of the turn, no more excessive load, all good.

1 hour ago, Tirefryr said:

I'm going to bet it a power steering issue causing strain on the pump which causes excessive parasitic drag.  This could cause belt slippage, or tensioner issues which means the alt struggles while turning.  Come out of the turn, no more excessive load, all good.

A valid idea, but I’ve never felt anything out of the ordinary whatsoever in my steering.. I’ve driven without or with a bad pump on previous vehicles before. The issue also happens when coming to a stop in a straight line as well though.. From what I’ve been reading, I am starting to think it has more to do with the alt Control settings that are in the PCM... but I’m not sure how I can address that

 My money is on the ECM. I had a Honda from that era that did the same thing. I validated through research that it was infact a “fuel economy mode” in the ECM.  That did not necessarily correspond with speed or voltage load.  Mine would usually do it after I got off the interstate. 

 It is completely normal and I would not stress over it. Mostly because there’s nothing you can do about it. Other than installing an independent charging system. 

 What/where do you have the voltage gauge wired up to?

 And for the record. If the amplifiers are wired directly to the battery and one has done the big three, the factory “battery current sensor” is bypassed. So the ECM does not recognize the amplifiers voltage draw through the “battery current sensor”.