Looking for some comparisons:

Normal hwy driving w/or w/o lights on... 13.4 - 13.9

When touching the brakes - again lights either on or off (for just a moment)- it spikes to 14.8-14.9 then finds it's way back down to 13.9.

Just noticed the "braking" varience today.

Sometimes when I start the car from cold - maybe it's sat for a couple days -
14.8 - 14.9 seems the norm on my car for maybe 1/2 hour or so.

Other's experiences?

Thanks!

 

Mine hovers at 14.5 and I was thinking that was a little on the high side. I believe they are gel-cell batteries so they may be designed to handle that.

ChuckJ

 

Normal. On cold days 15.2.

The alternator engages when you touch the brakes. It's part of the gas saving features

 

Thanks for following up!

The concern for me was that it's very close to the max red zone.....

 

13.9 - 14.1

Frank C.

 

16 is bad. Less is ok.

 

Mine stays in 14V range.

 

+1

Also goes up when you select sports mode or sports+ (Assuming if it is not high already due to cold ambient temp.)

 

Why does the voltage go higher in the cold? I would've thought too low was bad.

 

Speaking of which, I de-activated the gas saving feature several months ago as it was freaking me out and as I switched to sport mode on a full time basis. I decided to check if the feature still worked last week and it does not any longer (in normal mode of course). My Voltage is in the mid-14's. What do you guys think? Battery starting to go? 20K miles, 2 years old.

 

14.5 average.

 

I thought maybe the car is running it high in anticipation of the electrical draw of heated seats, defroster and such?

During cold start when it is cold out, it reads up to 14.8 right away.

After driving an hour, it would drop back to 13.7. Not sure why that is.

 

Same exact thing for mine yesterday. Temps in the low 50's.

When I first got my 991 the vehicle gauge in the dash that shows all the readings didn't have the voltage preference selected. It wasn't till I added
it to the menu that I started to wonder/think too much etc.

Probably I should just unselect it & be in the dark ha ha

 

Shhhhh! If we complain the Porsche parents will program a software patch to fix the voltage display at 13.7.

If the battery dies the car won't start.

If the charging system malfunctions the car will tell you.


Perhaps we should display the altimeter instead

 

Mine hit 15V today.