Notices
928 Forum 1978-1995
Sponsored by:
Sponsored by: 928 Specialists

Strange battery drain / problem.

Thread Tools
 
Search this Thread
 
Old Apr 20, 2008 | 10:36 PM
  #16  
Mrmerlin's Avatar
Mrmerlin
Team Owner
20 Year Member
 
Joined: May 2004
Posts: 31,222
Likes: 4,213
From: Philly PA
Default

Roger WING
Reply
Old Apr 21, 2008 | 03:03 AM
  #17  
Bill Ball's Avatar
Bill Ball
Under the Lift
Lifetime Rennlist
Member
20 Year Member
 
Joined: Mar 2002
Posts: 18,648
Likes: 52
From: Buckeye, AZ
Default

Originally Posted by Alan
The main thing is to be really methodical and note all your findings - they won't be 100% repeatable but should be close if you ever need to backtrack & regroup. Random testing gets very confusing very fast....

Alan
Alan:

Man, is that ever the truth (learned the hard way)! Thank you for the follow-up.
Reply
Old Apr 21, 2008 | 04:57 AM
  #18  
Nicholbry's Avatar
Nicholbry
Rennlist Member
 
Joined: May 2007
Posts: 468
Likes: 4
From: Mississippi
Default

My battery drain problem (after 3 months of searching) turned out to be the overhead dome light between the sun visors. The plastic housing on the inside was cracked and was interfering w/ the metal tabs used to hold the bulb in place and supply electric current. The light would come on and go off perfectly fine for the most part. However, a few trips down a rough road surface was all it needed to vibrate the bulb and connections.

Then, it started throwing the fuse (which is actually when I narrowed down the light). I called Dave at 928 Specialists and he knew instantly that the overhead light was the problem. Sure enough, it was and quickly remedied.

You may have checked this already, but just throwing in my $0.02 in case it helps.
Reply
Old Apr 21, 2008 | 03:21 PM
  #19  
nhporsche87's Avatar
nhporsche87
Instructor
 
Joined: Dec 2005
Posts: 171
Likes: 0
From: New Hampshire
Default

I used a light tester, made it easier for a rookie like me, ended up being 2 systems, left the fuses out for now as they are not going to hurt at the moment. Fix em later. Left her for 2 weeks and started up yesterday without issue. Also cleaned all the grounds, ground strap, grounds behind the fuse box, can't hurt.

Reply
Old Apr 21, 2008 | 05:53 PM
  #20  
Alan's Avatar
Alan
Electron Wrangler
Lifetime Rennlist
Member
20 Year Member
 
Joined: Mar 2002
Posts: 13,660
Likes: 621
From: Phoenix AZ
Default

Dan - you got lucky if you can detect a current leak with test light - not quite sure how you used it but this is not usually a good method. Test lights can be useful for testing voltage levels (though rather intrusively) - but usually not for current conditions (they change the circuit behaviour quite radically if you use them in series this way).

For $20 (radio shack) you can get a DMM that will make the process much easier - I wouldn't start without one... But if it worked for you - good!

I actually have 6 multimeters 2 old analog ones, 2 DMM's and 2 clamp meters each has its uses and one of the analog ones is a dinky little minature thing I keep in my travelling kit - no batteries to worry about (just in case).

Alan
Reply
Old Jul 30, 2008 | 12:28 PM
  #21  
Alan's Avatar
Alan
Electron Wrangler
Lifetime Rennlist
Member
20 Year Member
 
Joined: Mar 2002
Posts: 13,660
Likes: 621
From: Phoenix AZ
Default

Bert its really not clear to me what problem you actually have..?

Its obvious you have an issue that the trickle charger/maintainer doesn't work correctly and tells you you have a faulty battery.

I understand you don't drive the car often and thats why you got the maintainer - however if the car holds charge for 3-4 weeks (sufficient to start the car OK) and then is getting close to the edge - thats not so odd - it may well be considered fairly normal. If the car totally discharges in 2 weeks you probably have a problem.

Here is some math: Battery is 75Ah, you'd never want to discharge to more than 50% so you have 37.5Ah to play with. If the car has a parasitic current of 50mA (a little high but not too bad) then in a week (168h) you deplete ~8.4Ah so you will deplete half the battery charge in ~4.5 weeks.

Maybe you don't have a real problem with the car - just the battery charging? (of course you also have the problem that you don't drive it often enough!)

Alan
Reply
Old Jul 30, 2008 | 12:38 PM
  #22  
bfellows's Avatar
bfellows
Thread Starter
Burning Brakes
 
Joined: Dec 2004
Posts: 819
Likes: 0
From: Staffordshire United Kingdom
Default

Originally Posted by Alan
(of course you also have the problem that you don't drive it often enough!)
Alan


You're absolutely right about not driving it enough! I'm ashamed of myself sometimes when look at the shark for not using it enough.

Back on topic, the battery will be dead flat in around 2 weeks - ruined my last one as the voltage dropped to 0.8v! Hence buying the battery maintainer to try and save my battery from complete discharge. I do definately have a problem with drain and fully intend to isolate it. I've just been after a short term fix as i'm fed up with jumping in the car and getting nothing so much as a click when i turn the key.
Reply




All times are GMT -3. The time now is 05:31 PM.

story-0
9 Vehicles Porsche Helped Engineer that Aren't Porsches

Slideshow: Long before engineering consulting became trendy, Porsche was quietly helping other automakers build everything from supercars to economy hatchbacks.

By Verdad Gallardo | 2026-05-15 12:44:44


VIEW MORE
story-1
9 Features and Characteristics That Only Porsche People Understand

Slideshow: Some brands build cars. Porsche builds traditions, obsessions, and a few habits that stopped making sense decades ago but somehow became part of the charm.

By Verdad Gallardo | 2026-05-13 18:46:13


VIEW MORE
story-2
I've Written 500 Rennlist Articles: Here's How Porsche Has Changed Along the Way

Slideshow: Six years and 500 Rennlist articles later, these are the biggest changes at Porsche.

By Joe Kucinski | 2026-05-11 09:52:55


VIEW MORE
story-3
10 Most Unnecessary Porsches Ever Built (And Why We Love Them)

Slideshow: Some Porsches exist for very specific reasons-others feel like they were built just to see if anyone would notice.

By Verdad Gallardo | 2026-05-06 18:00:32


VIEW MORE
story-4
Porsche 911 GT3 S/C vs 718 Spyder RS: 10 Categories, One Winner

Slideshow: Choosing between the 911 GT3 S/C and 718 Spyder RS in 10 key categories to determine one surprising winner.

By Joe Kucinski | 2026-05-05 12:51:46


VIEW MORE
story-5
This Builder Is Turning Heads With Its Slantnose 911 Creation

Slideshow: A small Polish tuner has reimagined the Porsche 911 Slantnose for the modern era, blending 1980s nostalgia with widebody tuning culture and serious performance upgrades.

By Verdad Gallardo | 2026-05-01 10:49:43


VIEW MORE
story-6
Porsche 911 GT3 Artisan Edition Pays Homage to Japanese Culture

Slideshow: Porsche has created a Japan-only 911 GT3 Artisan Edition that blends track-ready hardware with design cues inspired by traditional Japanese craftsmanship.

By Verdad Gallardo | 2026-04-28 19:37:40


VIEW MORE
story-7
Porsche Reveals Coupe Variant of the Electric Cayenne With a Fresh Look

Slideshow: Porsche's latest electric Cayenne Coupe blends dramatic styling with supercar acceleration, turning the brand's midsize SUV into a 1,139-horsepower flagship.

By Verdad Gallardo | 2026-04-27 19:39:30


VIEW MORE
story-8
10 Porsche Colors That Have More Personality Than Most People

Slideshow: Porsche's wildest paint colors aren't just shades-they're full-blown personalities on four wheels.

By Verdad Gallardo | 2026-04-27 19:38:13


VIEW MORE
story-9
Guntherwerks' Final Speedster Creation Is the Ultimate Porsche Restomod

Slideshow: The last of the Speedsters doesn't just close a chapter, it makes quite the bold, air-cooled statement.

By Verdad Gallardo | 2026-04-22 17:55:04


VIEW MORE