dmatrixs

What voltage should my Alternator be spitting out?

I recently took my car to get the battery checked.
Everything read ok, battery good and charging well.
Their voltmeter was reading my alternator at 13.5v.
But when they unplugged the battery while the car was on and running, the car cut off. Meaning the car was still using power from the battery.
I find that to be odd if the car is suppose to run off of the alternator while running.

I just ordered this, , from amazon waiting for it to come in so that I can monitor my charging system to see any fluctuations.

So is 13.5 too low for our vehicles? What would cause my car to just cut off like that when disconnected from the battery.

Thanks in advance guys.

530inOK

13.5v may be a little low. Mine measured 13.9 at the battery with the car running. Pull the alternator and have it load tested at a parts store if you suspect it.
I would think it normal the car shut down when you disconnected the battery and isn't recommended. The electronics of these cars are sensitive to low voltage.

healthservices

Never a good idea to remove the battery source while the car is running on a late model car. This is a old school shade tree trick that can have the potential to do serious damage on some expensive electronics.

dmatrixs

Hmmm. Thanks for the tips guys. Still what is a good alternator voltage. What happened is that I was sitting in the car one day with it on and running, and all of a sudden the car died. I had to get a jump to get the car running again.

pcy

Based on the above info, I'd say the alternator and/or the voltage regulator on the alternator needs replacement.
You can have the alternator rebuilt or buy a re-manufactured unit.

If I were you, I'd buy a re-manufactured alternator and install it. This way, I wouldn't have to guess whether the alternator is bad or the voltage regulator is bad.

sanjsanj

Was out driving earlier with the volts showing on the secret obc menu.

On key position 1 it was showing 12.6v, key position 3 before startup, it was showing 11.9 v, during startup it momentarily popped down to 8.5v, (normally mine only pops down to 10.Xv) and once started and settled, it would stay between 14.7-15.0v. Switching on the rear window heater and it momentarily dropped to 14.1 before going back to the stable 14.9v.

Apparently, normal charging is supposed to be 14.4v. I've recently replaced my battery without resetting the IBS though, so this may be the reason why my car is pumping out a slightly higher voltage.


It would be great to hear more members' voltage readings...

dmatrixs

Did you code your vehicle to show the voltages?
I have INPA would I be able to do the same?

sanjsanj

No, just use menu 9 on the secret OBC menu... http://lmgtfy.com/?q=secret+obc+menu

dmatrixs

Here are my numbers:

Key Position 1: 12.0v
Pressing start: 11.5v
Vehicle Running: Gradually goes up to 13.9v/14.0v from 11.5v

While driving it stays around 14.0v +/-.1

Those numbers I don't think are too great for these cars.

Are these numbers just the battery or alternator as well?

l1tech

There is more to charging voltage than what most people think. The voltage that you see is dependant on outside temperature, state of battery charge, electricial load on the system and also engine rpm.