1FastRedSC

Is the voltage meter on the dash known for being accurate or inaccurate? I noticed for the first time yesterday that it's appearant voltage was like 12.3 volts while the car's running. I'm told that 13 volts is what's supposed to be normal while running so what gives? When i get home from work i'll probably check the battery voltage with a fluke.

threesticks1

Mine isn't very accurate. Its close but not right. It indicates about 1 volt low according to the two VOMs that I have.

IceShark

The in dash gauge is usually fairly accurate but can be off. Don't conclude it is junk if you measure at the battery and find voltage higher. You will loose quite a bit of voltage from the run over to and through the fuse/relay box. Especially if you have a bunch of current draws on like your lighting. So you may start off with 14.0v at the battery but resistance will bleed off a volt and a half or more (like you are seeing) by the time it gets to the dash meter.

This phenomenon is why I sell the supplemental positive in the battery cable kit and just remove the whole current draw off the OEM system with the headlight kit.

Porsche just doesn't do a very good job on electrical systems.

I also see you are in NM. How hot is it in your area? The hotter it is the lower the voltage output from the alternator. So make sure the cooling duct and heat shield are in place and don't have holes in the hose. You also may wish to put in a replacement voltage regulator which is set higher (say 14.4v) like the one I sell.

Before I started all this electrical upgrade stuff my dash meter was usually 12 volts or lower. Now it sits at a hair under 14, under load.

1FastRedSC

Well without any load just running it's sits at 12.4 volts. When fans kick on with stereo and headlights on it's doesn't budge. So there's no voltage fluctuation, but it just stays at 12.4. I'm going to check it when i get home, i just worry that it'll leave me at work. How much does that voltage regulator you sell go for? And does it matter that i have an alternator out of an S2? I know originally that the back of the alternator originally had nothing behind it, but when i replaced it with the S2 alt, it has that plastic curved cone behind it. I was contemplating dropping the ac since i don't use it. If i went with the conversion where the alt sits and the very bottom where the ac sits now, would it make a difference in cooling for the alt? -thanks in advance

IceShark

Do you have the cooling hose that attaches to the alternator heat shield cone? If not, you are not getting the cooler air from the scoop in the front of the bumper. The diodes inside the alternator do not like to get hot! Get that cooling hose on and whatever you do with A/C won't matter. It is a 60mm diameter hose.

The S2 uses the same 115 amp Bosch alternator as your 88 944. The adjustable voltage regulator with attached brushes that I sell is $21, including shipping in the USA.

Something is strange that your voltage isn't moving when you load up the electrical system. Turn on everything like rear window heater and heater/AC fan, lights on high beam, etc. See what happens. You will drop on voltage so that will be a good check.

If you want the adjustable voltage regulator just drop me an email at wraydan@msn.com , I'll send you my address and just mail a check to me.

gleamingred944

Don't forget that battery voltage goes down as temperature goes up. Someone asked this question last winter and I measured 14.1V, at -30F. Today it's +95F and I'm getting about 12.6V

My gauge is as accurate as I can read it. Your's may differ of course.

IceShark

gleaming, battery voltage or alternator output? The battery voltage will tend to go up within reasonable temperature increase changes.

Alternator output goes the other way as you describe due to the diode pack being hot and as well as the voltage regulator cutting down the output. But I think you may have an equipment problem. 14.1v to 12.6v is way too much.

We have gotten up to 90+F and I am still running pretty close to 14.0 at the battery with a hot engine bay at idle.

Ag951

My DMM reads ~4.5V off of the battery, and the in-dash gauge doesn't register at all. Hmm...

IceShark

Ag951, you must have that special 3 volt version that Porsche made. While everyone else is going to 36/42 volt, Porsche is going backwards. <img border="0" title="" alt="[Wink]" src="wink.gif" />

Hans

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by IceShark:
<strong>Ag951, you must have that special 3 volt version that Porsche made. While everyone else is going to 36/42 volt, Porsche is going backwards. <img border="0" title="" alt="[Wink]" src="wink.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Ice, NO.
It is a step forward... Low energy consumption...*)
Thank god its friday.
TakeCare

1FastRedSC

Well gentlemen, i tested it yesterday. Things seem normal. And this morning under initial startup, once idling the "gauge" went right up to 13.4 volts. Once i got to work and let it idle a bit, it dropped to 12.4 volts again. It does drop under load but you have really, and i mean really have to look at the gauge for any fluctuation.

Ag951

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by IceShark:
<strong>Ag951, you must have that special 3 volt version that Porsche made. While everyone else is going to 36/42 volt, Porsche is going backwards. <img border="0" title="" alt="[Wink]" src="wink.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Something tells me I shouldn't have left the door open for a week. Fortunately, there's a brand new optima redtop from 944racing.com on my doorstep right now.