Hey guys. I was wandering if anyone can help me out with a little problem. I got 2006 Mustang V6. Few days ago I start getting a dashboard warning signal that reads: "CHECK CHARGING SYSTEM" When it comes on it's just for 20-30 sec. at the time and when I push system check button it shows everything is ok. I recently replaced the battery and the alternator so I checked connections thinking that might be the problem but everything is fine there. What could be the problem here?
Thanks.

 

What is the voltage across the battery terminals with the engine idling?

 

12-13V

 

That's low. It should be above 13 volts. A fully charged battery is generally 12.6-12.7 volts. The alternator needs to put out more voltage than the battery in order to charge properly.

 

So you think it moght be a problem with the alternator? I mean, is that something that would happen even though it's new?

 

The alternator could be bad even though it's new. I'd be looking for a minimum of 13.2 volts at idle, but would be happier with 13.5 or more. Take a reading at about 2000 rpm, and see if you get a minimum of 13.5 volts. I'd be happier with at least 13.8 volts.

Does the battery (car not running) give you a reading of 12.6-12.7 volts if you take a good run on the highway and let the car sit overnight to get rid of the surface charge?

Why did you replace the battery and alternator in the first place?

 

The battery was about a year ago. It just wouldn't hold a charge. And alternator just died on me out of nowhere. Oh and I checked the battery charge after letting car sit overnight and it's at 12.8V