Odd Voltage readings

[bigfish3]

Does anyone else pay attention to the volt meter?

I am seeing odd things happen, it seems to be speed dependent.

When I am coasting at highway speed, the voltmeter climbs to 14.2, under throttle, hard acceleration it drops to 12.xx.

In the old days (I am an old bastard}, a fully charged battery in like new condition would read 13.2.

I don't think that there is a standalone voltage regulator these days, I am pretty sure everything is in the alternator.

Could this be an indication of a failing alternator?

Sponsored

 

[FreePenguin]

you have a smart battery charging system. its normal

 

[W.O.T. Stang]

Everything you need to know about what you are asking about and then some. If you are interested.

https://www.motor.com/magazine-summary/are-you-smarter-than-a-smart-charging-system/

 

[engineermike]

Alternator output voltage is controlled by the pcm as a function of battery temp, fuel demand, and other things.

 

[SAL-E]

Normal when battery is fully charged.

 

[brianbr]

Mine does the same thing. Even though the alternator demand is around 14.4v alternator output varies from 12.2 to 15 on mine. I was told it's normal even though every time go to start the car battery voltage is at 12.0/12.1. Having battery voltage drop under wot is the dumbest thing I have ever heard of. I wish there was a way to change it.

 

[engineermike]

I don't know what "launch" is, but maybe that's it. Note that voltage does go back up under high fuel demand:

 

[brianbr]

It's crazy how much the pcm controls. I'll have to check a log when I get home. If I remember correctly even at wot the voltage was still in the 12v range.

 

[engineermike]

It's crazy how much the pcm controls...

It is absolutely shocking and mind-boggling what these pcms do.

The gdi injector and pump control is insane.

Sponsored