Alternator/Regulator Voltage over 15V

[RichieRocket]

Not sure if this is the right forum for this? There is no electrical issues forum?

Since I have been running with the Ultra-gauge, the MAX Voltage alarm has gone off a few times. I looked thru the manual, by default the max voltage alarm is turned on and set to 14.9V. So I went into the alarm settings and bumped it up to 15.2V

Well yesterday, the alarm goes off again...voltage is up to 15.25V! When I got home, I hooked up the multi-meter directly to the battery and it showed the same value +/- 0.1V

That seemed high to me, so I did a quick search, some websites say the voltage at higher rpm (1500rpm) should get up to 14.5V. Mine was 15.25 at idle!

One website said if it's above 14.8V, the regulator is not working properly and is overcharging the lead-acid battery...

The actual dashboard warning light has not gone off, but that may only be a low alert?

Any comments? I gonna ask the dealer to check it during the first oil-change.

 

[Sonic]

This is the proper spot, thank you for that. I'll let the "experts" answer your question, because I don't know about the battery and charging systems on cars.

 

[wasteoffilm]

Our alternator testing machine considers 13.5-15.5v acceptable for a passing grade. Most automotive electrical devices, that I have noticed, are rated for 10-16v operation. I don't think you need to worry.

 

[wingman]

I had that happen to me with my UG. I turned the alarm off. Thanks for the insight wasteoffilm.

 

[blackedout]

I have also had this issue, actually had mine get up to 15.5 but now i have a new issue. Today I was sitting at the taco bell drive thru and my ultragauge alarm went off for low voltage. I have it set for 12.45 volts which is battery voltage and it had dropped down to 12.33. I drove it a few more times and the problem seems to be that when I first start it I'm around 14.5 then after driving for approximately 5 minutes it starts fluctuating between 12.15 to 12.5. I have an appointment with the dealer Friday as I've only had the car for 3 weeks but this concerns me as I plan on adding my kicker zx750.1 and kicker cvr soon but not with a failing alternator. Has anyone else had this issue?

 

[omniman]

Both are normal due to the power managment system.13.9-15.5 is normal charge mode.And 12.5-13.1 is fuel economy mode.There is 6 modes total if you look at your battery cable you will see a clamp around the cable it monitors and adjust to differnt conditions.IT should give you a warning light if there was a problem.Hope this helps if you still think there is a problem have it checked out.The info is from GM service info on line

 

[blackedout]

OK thanks... just didn't want to install my stereo system then have a problem and the dealer try to blame it on the install.

 

[gsxr1000]

mine reads (High) ~15 volts for a few minutes then ramps down to mid 13.... i think this is a quick charge feature

 

[beaslbob]

Same thing here with my ultra guage.

Tried one of those led cigareete lighter testers and it show high voltage right after startup which went down to normal after 30 minutes or so of driving.

My gut feel is that initially it probably is too high but overall it seems to be functionally normally. but then I could be wrong so will keep an eye on this thread.

my .02

 

[omniman]

my post is from the GM service manual online.Both are normal.

 

[Machine]

All this is absolutely normal, the charging system is closely monitored and tightly controlled by the body control module. Omniman is correct; when the vehicle is started, voltage is initially high to bring the battery back from the start and then will soon settle back. System voltage is not always an indicator of battery charging state. During high rpm and power enrichment, high voltage helps things like ignition and camshaft controllers to operate better. A lot of it is also fuel milage, the alternator is a drain on engine power, and that can be reduced.

That being said, I cannot say how well it would sustain a amplifier setup. I am not sure on the exact specs on our car, but I would say a properly sized capacitor is in order, as I doubt there is much extra built into the charging system on this car.