Strange electrical gremlin - check charging system

[maclean]

OK, so when I accelerate briskly, the check charging system warning is coming on in the information center, and the red battery lamp illuminates.

It stops as soon as I reduce engine speed, and the charge gauge does not indicate a drop in voltage.

Any thoughts?

 

[Verno]

OK, so when I accelerate briskly, the check charging system warning is coming on in the information center, and the red battery lamp illuminates.

It stops as soon as I reduce engine speed, and the charge gauge does not indicate a drop in voltage.

Any thoughts?

I had this problem several yrs ago, but it was on a non-serpentine belt motor. Turned out my alt belt was slipping at high rpm's. My first thought would be check your belt for signs of wear/slipping (is the groove side shiny) Slipping only at higher RPM's could be early sign of need for change!

 

[jrford]

I second that check the belt, or tensoner, it should be fairly tight. If that looks good then maybe the alt.

 

[maclean]

I had this problem several yrs ago, but it was on a non-serpentine belt motor. Turned out my alt belt was slipping at high rpm's. My first thought would be check your belt for signs of wear/slipping (is the groove side shiny) Slipping only at higher RPM's could be early sign of need for change!

Thanks, I'll check that!

Anyone else have any suggestions?

 

[maclean]

It's sort of looking like it might be the alternator.

Engine off, 12.4 volts at the battery.

Engine on, 14.0 volts at the battery with no accessories on.

Engine on, 11.1 volts at the battery with lights and heater on.

Maybe the increased demand on the coil at high RPM is just over taxing it?

I also notice a marked dimming of the headlights/dash lamps in drive at a stop.

 

[Verno]

It's sort of looking like it might be the alternator.

Engine off, 12.4 volts at the battery.

Engine on, 14.0 volts at the battery with no accessories on.

Engine on, 11.1 volts at the battery with lights and heater on.

Maybe the increased demand on the coil at high RPM is just over taxing it?

I also notice a marked dimming of the headlights/dash lamps in drive at a stop.

Youcan have the alt and battery tested at most auto parts stores, this will help as a "load test" will determine if faulty.

 

[maclean]

Well, sure enough it was a bad alternator.

Fixed it, and took the opportunity to replace the belt.