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Registered
Join Date: Oct 2006
Location: MYR S.C.
Posts: 17,321
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battery vs charging voltage
if you ever thought a battery was just a battery and charging voltage was just voltage, you might want to read this.
im soooo confused  http://www.landiss.com/battery.htm
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86 930 94kmiles [_  _] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD88 BMW 325is 200K+ SOLD 03 BMW 330CI 220K:: [_ _] RUNNING: [__] NOT RUNNING:01 suburban 330K:: [_ _] RUNNING: [__] NOT RUNNING:RACE CAR:: sold |
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07-28-2009, 08:21 AM
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Model Citizen
Join Date: May 2007
Location: The Voodoo Lounge
Posts: 18,898
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Since I'm in the middle of an alternator issue right now, I found this to be pretty interesting, and now I am looking forward to seeing where my new VR readings are.
and, in a similar vein,do similar VR's/alternators available for the porsche have different outputs, or is there a specification?
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"I would be a tone-deaf heathen if I didn't call the engine astounding. If it had been invented solely to make noise, there would be shrines to it in Rome" Last edited by herr_oberst; 07-28-2009 at 10:00 AM.. |
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07-28-2009, 09:58 AM
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Registered
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Quote:
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86 930 94kmiles [_ _] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD88 BMW 325is 200K+ SOLD 03 BMW 330CI 220K:: [_ _] RUNNING: [__] NOT RUNNING:01 suburban 330K:: [_ _] RUNNING: [__] NOT RUNNING:RACE CAR:: sold |
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07-28-2009, 10:37 AM
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Registered
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Location: MYR S.C.
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mine is 14.4v with an interstate battery, i did not look to see what kind.
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86 930 94kmiles [_ _] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD88 BMW 325is 200K+ SOLD 03 BMW 330CI 220K:: [_ _] RUNNING: [__] NOT RUNNING:01 suburban 330K:: [_ _] RUNNING: [__] NOT RUNNING:RACE CAR:: sold |
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07-30-2009, 09:44 AM
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Registered
Join Date: Mar 1999
Location: Cornwall-on-Hudson, New York, USA
Posts: 4,499
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Interesting. No wonder I've had several years of minor battery issues: 25-year-old Porsche with assumedly a 25-year-old VR setting even though the alternator is new, trying to charge a new, modern Interstate battery that requires something between 14.3 and 14.8 volts, according to this document.
Wayne needs to read this: He once told me, when I complained that the alternator he'd sold me wasn't putting out enough, that "13.8 volts is plenty--more and you'll cook the battery." Well, apparently at least the old farts at Bosch would agree with him... So how do you turn up a VR to create the correct charge? Anybody know?
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Stephan Wilkinson '83 911SC Gold-Plated Porsche '04 replacement Boxster |
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07-30-2009, 09:53 AM
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Moderator
Join Date: Dec 2001
Posts: 9,569
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You can't change the "set-point" on the VR, unless it's an adjustable one like a Transpo IB301A (an external voltage regulator).
What you CAN do with a 25-year old car is make absolutely certain that the full charging voltage is making it to the battery by keeping the cable ends free of corrosion. Corrosion creates a high resistance which results in a voltage drop. Likewise I don't really like Optima batteries for this reason, with their 15 volt charging voltage. They don't fit well in a LWB
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'66 911 #304065 Irischgruen ‘96 993 Carrera 2 Polarsilber '81 R65 Ex-'71 911 PCA C-Stock Club Racer #806 (Sold 5/15/13) Ex-'88 Carrera (Sold 3/29/02) Ex-'91 Carrera 2 Cabriolet (Sold 8/20/04) Ex-'89 944 Turbo S (Sold 8/21/20) |
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07-30-2009, 10:00 AM
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Get off my lawn!
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I guess I was one of the folks that thought 13 volts was plenty. My 85 Carrera puts out 14 volts most of the time. I was worried that it was a little high. I guess I am right about where I need to be. The only time it drops is at idle with the A/C cranked up and the headlight on.
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Glen 49 Year member of the Porsche Club of America 1985 911 Carrera; 2017 Macan 1986 El Camino with Fuel Injected 350 Crate Engine My Motto: I will never be too old to have a happy childhood! |
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07-30-2009, 10:36 AM
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Carrera
