Fluctuating voltage gage

[Dixieman]

Fluctuating voltage gage, sometimes at 14 then drops to 12. Do these alternators charge as needed or should they be charging 14 + all the time.

 

[mb1500]

Year
Make
Model...

 

[Doubeleive]

Fluctuating voltage gage, sometimes at 14 then drops to 12. Do these alternators charge as needed or should they be charging 14 + all the time.

normal, unless it is dancing a jig while the blinker is on or something then it would be time to get a new battery

 

[Dixieman]

Thanks for the replies. sorry for the double post. cannot figure out how to delete.

2011 tahoe ls

 

[me88]

The ECM controls the alternator output, there are 6(!) different charging modes that the computer chooses from depending on temperature, electrical load, headlights on or off, ...

 

[Dixieman]

Guess I need to check battery cables and starter. Sounds like weak battery most of the time when cranking even with new battery

 

[swathdiver]

Guess I need to check battery cables and starter. Sounds like weak battery most of the time when cranking even with new battery

Look up the terms RVC and EPM. Lots of short trips will eventually drain the battery down. If that is normal, get a tender for it.

 

[Cantrepeat]

Fluctuating voltage gage, sometimes at 14 then drops to 12. Do these alternators charge as needed or should they be charging 14 + all the time.

I'm under the impression that newer alternator/charging systems actually shut off when the power is not needed. Thus, the gauge will show 12v or lower and when on show a normal 13-14v.

 

[Scoots]

I'm under the impression that newer alternator/charging systems actually shut off when the power is not needed. Thus, the gauge will show 12v or lower and when on show a normal 13-14v.

My 2012 Tahoe is also between 12-14+ I noticed on a road trip so replaced alternator since the Tahoe has 98,000 on it
After replacing for the first 10 min 14+ then dropped again to 12-13 for a few minutes?

 

[Scoots]

I'm under the impression that newer alternator/charging systems actually shut off when the power is not needed. Thus, the gauge will show 12v or lower and when on show a normal 13-14v.

Was this confirmed? That would be great
Thank You