f4 plt

Anyone know the max voltage for the Cayenne S that Porsche considers in the "normal range" Mine is showing 14.8-14.9 at cruise. I would think this would indicate a voltage regulator or alternator issue possibly combined with a bad battery. This high voltage reading is recent but I have had various electrical accessory anomalies. these would include a random blooming of the brightness of the nav screen then returning to normal brightness on its own. Also sometimes when you disconnect the cruise control you cannot re-connect it without first turning the engine off and then re-starting which sounds like a software re-boot. The vehicle is on its third nave unit since new.

The dealer has not been able to find any codes that point at electrical issues which is normal for random electrical issues.

So back to the question, what is considered the max voltage within the "normal" range. My guess is 13.4-13-6 is normal and max allowable would be some where around 14.5 or so unless the battery has been drained. comments

grohgreg

What I've come to accept as the normal range is 12.2v to 14.9v. And after nearly 17 months of ownership, I'm still unable to determine a pattern. What I have come to realize though, is that this car doesn't separate battery for the electronics (like my Mercedes). So there's always a variable load on the single battery - whether the alternator is turning or not.

But I've never had any of the other issues you describe. So going through 3 nav units in as many years is definitely a problem. It doesn't however, seem to be related to what you see on the voltmeter.

//greg//

CaptJim

whatever we are talking about, I first want to say that the guage on the dash probabally isnt the best to determine what the real voltage is. I would only trust a nice digital meter. I noticed mile looks above 14v, but that isn't always a bad thing, especially if the regulator is trying to Maritain load.

Electronics can handle the range, they are full of filters to make varying voltages internally.

On my boat, and in other cars, higher voltages are a sign to me that the regulator isn't going to last very much longer. On the Porsche, is the regulator on the alternator? Start by changing the alternator. I have local auto electric shops that do nothing but starters and alternators around my area that are very knowledgeable. I am sure you have some too.

f4 plt

Greg:
I agree the nav unit issues were Nav unit issues, one was a bad bluetooth module, another was failure of the memory storage etc. The cruise control I think is a random software glitch. as a simple re boot always corrects it infill the next time.

the voltage issue bothers me especially since I use it for trips and the additional fact that the battery drained rather quickly with the radio on for a short time after shutting the engine and the temperature was in the upper 60's so not a cold issue.

There have been some other minor accessory mechanical issues over the two years but basically a great vehicle and only as it comes near the ned of the warranty and with these latest problem to I begin to question keeping it. Must have been a Monday car.

CaptJim

You just fixed your own problem. The alternator/regulator is compensating for a bad battery. Get that battery out of your car, you should be able to leave your lights on for 4 hours and still have a good battery. I also recommend a float charger like a battery tender.

f4 plt

I would agree using a tender if the vehicle sat but as you can see with 42,000 miles in just under 3 hears the Cayenne is not a garage queen. My wife has had her 2014 Diesel Cayenne only since the end of July and she already has 14,000 miles on it and then we have the fun Porsche and it gets driven. Texas is a big place.

CaptJim

do you think you have a good battery too...

gnat

I've also seen my voltage all over the place. I did put a voltmeter on it and it really is all over the place.

My dealer at the time said it was normal and took me out in 3 others to prove it. Drives me nuts as historically odd or wildly fluctuating values are a good indication that you have an issue in your electrical system.

ndx

Where is the digital Voltometer my 2011 CS doesn't have it.

The voltage that you are saying seems to be OK

Thank you

f4 plt

Until this recent episode, yes I had no reason to question the battery's health as the Cayenne started quickly in both hot and cold. But, with the voltage fluctuations and the fact it drained so quickly the other day I would lean towards it being damaged. I also believe that most probably either the alternator or the voltage regulator is bad, perhaps both. Bottom line if they give the pepper back with no fix to the electrical issues I will not have confidence to take it far from home. As I said at the beginning unfortunately this vehicle has had a history of issues all over the map. My wife's 2014 diesel has been trouble free. Did i mention a Monday car

Slow Guy

The voltage reading on my "S" was always pretty much right on the 14v mark, varied very little. The voltage on the GTS reads much higher consistently, it will only drop down slightly during long drives (250 mi +). I put in a new battery thinking that may be the cause, no change. I've had a couple of flaky issues (inc Check Engine errors) that just went away before I could get to the dealer. I'm seriously considering putting in (temporarily) a digital volt meter that will record the highest and lowest voltage, should be easy to attach and leave connected since the battery is under the driver's seat. I may not have a problem at all but I would like to verify.

gnat

It's one of the options you can select on the Info screen of the MFD.