[fasteddie6714]

Just a quick question: What does your Voltage read on dash gauge when under way. Mine is just a bit above 12v, like a needle width above the 12v mark. It does not vary with rpm. Iam forced to use battery minder to maintain battery level. This has been the same with three different batteries. All replies appreciated.

Partial Post: Please Login or Register to read the full post.

[rl968]

What does battery read with your car running, should be about 13.8. If not, you have a bad alternator.



If you let your car sit and battery is dropping below 12, you have a drain somewhere. Check to make sure your interior light switches are off (one in hatch, one by rear view mirror. Should be in center position.). If these are good, you have a drain somewhere else.





If your battery isn't dropping and battery reads 13.8 with car running, I'd suspect the gauge.



My gauge reads a bit above half way.

Partial Post: Please Login or Register to read the full post.

[DaveN]

Our voltage gauges are quite temperamental. Mine reads about 12.5-13 most of the time but it's never consistent. I know my alternator and regulator are working properly. After my engine rebuild my gauge read 14.5 volts! Yikes. After a few days it settled down; it hadn't seen electrons for 8 months.

Partial Post: Please Login or Register to read the full post.

[ds968]

Same here, alternator and regulator checked multiple times, everything working perfectly. But for what has now been more than ten years my voltage gauge has barely managed to stay a hair or so above the 12 v line ( while driving ) . Never had issues starting, but then again I can't get more than three or four years out of a battery no matter what..even the Interstate . But that's also the typical longevity of the batteries in all the other four cars we have . Lucky I don't drive a Tesla, I'd have to spend $ 30,000 every three or four years on a new battery :-) :-).

Partial Post: Please Login or Register to read the full post.

[tamathumper]

My needle is usually as you describe, about 1 width above the lower mark.



All your grounds are clean, and major cables from alternator / starter / battery in excellent condition - even underneath the large "sheath" that covers them? Look at the large cable that connects to the back of the alternator - if it's bare and green, that's one thing to address.



Secondly, check things with motors, like the seats, windows, hatch wiper (if any), and make sure they're not still "on" when you turn off the car - they've been known to stick on the 944's and drain the battery, and the same might be true for the 968 although it's a little different about things working after you turn off the car and open a door.



Pull fuses one at a time and see if your "drain" diminishes. It only takes a few minutes.

Partial Post: Please Login or Register to read the full post.

[Paul W]

My voltmeter is just slightly above 12 when running, but when the ambient is colder outside, you should see a rise in the volt meter until the regulator warms up....I will see 14 VDC initially on a 50 F day for a few minutes.

Partial Post: Please Login or Register to read the full post.

[986boxster1998]

Eddie, how are your interior lock pulls? If you pull up on them does the plastic seperate from the door (they can be brittle so if you haven't already noticed an issue be gentle with them)?



My car just recently started to have a battery drain, where if I let it sit more then a few days it dead and won't turn over (previously it would sit for months and start right up). I tested the battery voltage off the car and its maintaining voltage and a battery shop told me what CCA is, so thats been ruled out.



The only thing that has changed recently is that a local key shop attempted to try an cut a key for the car and ended up breaking the passenger interior lock pull. Upon opening up the door I found that the wires to the LED had been stripped.



I'm thikning of just removing the LED units as they unplug and seeing what happens, although I've heard from others that the battery can still drain even with bulbs and other things unpluged so I don't know if it will help.

Partial Post: Please Login or Register to read the full post.

[Inkedupfatboy]

I have had my car since April - We put an OEM Porsche battery in it. After getting the car finally driveable my mechanic had it for a while and then told me he needed to warranty out the battery.



New battery (again Porsche OEM) has been in almost two months and no problems so far - meter reads just as others around 13 ish maybe a tad higher.



I keep the car in the garage, top down and unlocked with the key sitting next to shifter so my lock LED's and alarm are not activated - I am thinking of disconnecting the clock as I don't use it and don't really care if it runs. It's wrong anyways.

Partial Post: Please Login or Register to read the full post.

[fasteddie6714]

Thanks for the posts and the help. Eddie

Partial Post: Please Login or Register to read the full post.

[MCL968]

Mine always reads around 12v, but it starts and runs great, so I just assumed it was the gauge being a little nonlinear.



In a related vein, does anyone know about "adjustable" voltage regulators, and how to tell if a regulator is adjustable? Also, my alternator wire is also bare and in need of replacement. Battery cables are fine, I just need to swap out this wire. Any suggestions or tips to make the process easier or perhaps more effective? Would it make more sense to run it directly to the battery instead of to the starter post?

Partial Post: Please Login or Register to read the full post.

[gbarrier]

Seems like the OEM value regulator does not maintain batteries at the level that modern batteries like to be maintained at. Many alternator rebuild shops have available regulators with a little higher value or, my favorite, an adjustable one. Maintaining the level around a good strong 14V will allow you to let the car set for a longer period and still start. With all that done, clean grounds and the gauge where it contacts the panel. Bet that will also get your reading more in line with actual voltage.

Partial Post: Please Login or Register to read the full post.

[prj24149]

From what I've read, the volt gauge on these cars isn't that accurate. Mine was reading just a hair above 12V but when I put a DVM on the battery (while the car was running) I got 13.5V.

So last time I had the gauges out of the car for repairing the odometer I found that the voltage guage(meter) has a adjustment screw. I adjusted it slightly and now it reads 13.5V while running.

Except of course when the air conditioner is on and all the fans are on. Then it reads 12V.

Partial Post: Please Login or Register to read the full post.

[Davbert55]

I had the same issue with mine. I had a battery load diagnostic test done. The voltage under load (lights and AC) was about 12.8. I replaced the alternator brush/regulator assembly. the Brushes were obviously worn when compared to new. If the brushes are good, check the alternator belt tension. it will slip under load. When it's hot it won't squeal to let you know.



Dave

Partial Post: Please Login or Register to read the full post.

[flash]

the gauges generally read low on these cars. using a real voltmeter at the batery is a better test.



batteries don't last more than about 3 years these days on average.



make sure they are topped up with distilled water.



every time you kill a battery, you lose about 5% of its ability to charge. do that a few times, and it won't take much to kill it.



make sure your cable connectors are clean and tight. loose ones won't charge fully.



many aftermarket stereos have a large parasitic draw. use an ammeter to determine what that is. decks with removable faces are the worst. remove the face, and the draw will drop dramatically on most of them.

Partial Post: Please Login or Register to read the full post.

[ds968]

On my tip the needle rarely drops below 14 ( in any situation - sitting, driving, lights on / off, etc etc ) and when it does it's barely below that line so at least 13.5 at its lowest. On my manual, even now with a brand new battery the needle barely moves above the 12 marker, just as indicated in my earlier post here.

Partial Post: Please Login or Register to read the full post.

[WJH]

These aren't really precision gauges. At 20 years of age they basically show whether the alternator is working. Don't expect much more than that.

Partial Post: Please Login or Register to read the full post.

[Eric_Oz_S2]

Batteries last a lot longer when they are in the boot. Case in point, s2 battery lasted 6 years. E46 battery (again in boot) 11 years, still going.

Partial Post: Please Login or Register to read the full post.

[ds968]

[quote name='Eric_Oz_S2' timestamp='1391326502' post='154811']Batteries last a lot longer when they are in the boot. Case in point, s2 battery lasted 6 years. E46 battery (again in boot) 11 years, still going.[/quote]



Why is that ?

Partial Post: Please Login or Register to read the full post.

[Bulti]

Because of the heat of the engine?



Heat is what hurts and eventually kills a battery. In the warm(er) months your battery gets damaged so that it can not perform optimal in the winter, just when it needs the most 'amp-reserves' due to a decrease in efficiency. Because of that, people think the battery dies in the winter/cold months of the year, but it's really the opposite.



That is a least what I've been told by someone who should know, but it makes sense to me.

Partial Post: Please Login or Register to read the full post.

[paulzebo]

Engine heat is the biggest contributor. Not the heat by itself but the lack of ability for a battery to accept a charge at high under hood temperatures. Two years is about the useful life of a battery, under hood, at high temperatures in AZ. Some manufactures put the battery in a foam blanket to help insulate it from excessive under hood temperatures. Usually these are discarded when the battery is first exchanged and never replaced. This sets up the early failure of the second, third, ect, battery. The lack of ability to accept a charge at high temps is called thermal runaway. Here's a link on it pertaining to a 1.5v battery but the same participles apply to our 12.6v ones. It's also the one of the reasons the Boeing Dreamliner had battery issues.

TN-11001Thermal Runaway Detection Tech Note.pdf Size: 93.12 KB  Downloads: 7

http://www.google.co....60444564,d.aWc



Low voltage concerns at the battery are usually a voltage regulator issue. Higher volt ones are available. Do a Google search for Porsche Bosch voltage regulator. industry standard on new cars is now 14 volts. Here's a 14.5V model http://www.busdepot.com/068903803D You're not looking for a voltage regulator for a Porsche but rather the Bosch alternator.

Partial Post: Please Login or Register to read the full post.