Notices
Drivetrain Gearbox, Diffs & Driveshafts etc

Battery keeps going flat, even when replaced with a new one. Can ayone help?

Thread Tools
 
Search this Thread
 
Old Mar 4, 2003 | 02:57 PM
  #1  
Scoty's Avatar
Scoty
Thread Starter
Scooby Regular
 
Joined: Jan 2002
Posts: 4,056
Likes: 0
Question

Hello,

Can anyone help me with this please.

My car failed to start last week. (battery was flat first thing in the morning)

I got a jump start, and checked the Link module to see what voltage the alternator was putting to the battery.
It read 14.3 volts.

So I asumed my battery was nackered and the alternator was working, and got a new battery fitted. (same day)

Today the same thing has happened. The car fails to start because of a flat battery. Again, I got a jump start.
This time the Link reads 12.2v. I checked the earth strap, and the started motor for loose connections, but it looks OK. There is no corrosion on any of the terminals, and they are tight.

Can this still be the alternator that is faulty, even though the Link is showing that is is working OK?
Is there anything else I can check, maybey something simple....fuses

Thanks

Scoty
Reply
Old Mar 4, 2003 | 03:11 PM
  #2  
Scoty's Avatar
Scoty
Thread Starter
Scooby Regular
 
Joined: Jan 2002
Posts: 4,056
Likes: 0
Unhappy

Forgot, that the battery light in the dash stays on all the time when the car is running.
Reply
Old Mar 4, 2003 | 04:01 PM
  #3  
Andy.F's Avatar
Andy.F
Subaru Tuning Specialist
 
Joined: Jun 2002
Posts: 6,654
Likes: 1
From: 7.74 @179 mph 1/4 mile - road legal
Smile

Sounds like one of the diodes in your Alternator have failed. It will still charge with reduced current flow but will leak away battery current when standing idle.
Most auto electricians can replace the diodes / rectifier pack. Not too expensive, £20 ish IIRC.

Andy
Reply
Old Mar 4, 2003 | 04:23 PM
  #4  
LG John's Avatar
LG John
Scooby Regular
 
Joined: Mar 2002
Posts: 13,720
Likes: 0
From: Bradford
Post

Sounds like the car isn't being run enough. I would suggest you take it for a drive.......but.....

Are you sure you aren't leaving all that ice running
Reply
Old Mar 4, 2003 | 04:26 PM
  #5  
Andy.F's Avatar
Andy.F
Subaru Tuning Specialist
 
Joined: Jun 2002
Posts: 6,654
Likes: 1
From: 7.74 @179 mph 1/4 mile - road legal
Post

I'll hold him while you hit im Scoty
Reply
Old Mar 4, 2003 | 04:29 PM
  #6  
Scoty's Avatar
Scoty
Thread Starter
Scooby Regular
 
Joined: Jan 2002
Posts: 4,056
Likes: 0
Post

With pleasure Andy
Reply
Old Mar 4, 2003 | 04:35 PM
  #7  
LG John's Avatar
LG John
Scooby Regular
 
Joined: Mar 2002
Posts: 13,720
Likes: 0
From: Bradford
Post

He, He Hope you get it sorted. If its any consolation my battery is showing signs of weakness on startup
Reply
Old Mar 4, 2003 | 05:11 PM
  #8  
SCOSaltire's Avatar
SCOSaltire
Scooby Regular
 
Joined: Mar 2001
Posts: 1,809
Likes: 0
Post

lol
so is mine.. lights dim when locking the doors

Reply
Old Mar 4, 2003 | 05:16 PM
  #9  
LG John's Avatar
LG John
Scooby Regular
 
Joined: Mar 2002
Posts: 13,720
Likes: 0
From: Bradford
Wink

I had to switch my 'bright' switch to dim mode to conserve power
Reply
Old Mar 4, 2003 | 10:02 PM
  #10  
tweenierob's Avatar
tweenierob
Scooby Regular
 
Joined: Mar 2002
Posts: 4,338
Likes: 0
From: Fcon Power Writer
Post

Have you checked the drive belt??
A friend with a Golf had exactly the same prob, belt didnt screech at all..
Wouldnt start in the morning(flat batt)/light on whilst running/lights would dim whilst driving etc etc
Checked the voltage at idle and it was about 12.6v (not good) when i revved the engine the voltage dropped to 11.9v.....

Changed the drive belt and 'hey presto' 13.7v

I did try tightening the belt but it made no difference.

Just a thought??

Rob
Reply
Old Mar 5, 2003 | 12:19 PM
  #11  
Scoty's Avatar
Scoty
Thread Starter
Scooby Regular
 
Joined: Jan 2002
Posts: 4,056
Likes: 0
Thumbs up

Cheers Rob,

I checked the belt. It's in good nick and tight enough.

What Andy has said is going to be the fault probably.

Thanks for everyone's help.
Reply
Old Mar 7, 2003 | 03:10 PM
  #12  
mmurray75's Avatar
mmurray75
Scooby Regular
 
Joined: Dec 2002
Posts: 40
Likes: 0
Post

The way to tell if the diode has gone bad is to check the output of the altenator with a volt meter set to AC voltage. On a good alt you should see around 0.03v AC on a bad one the AC voltage will be much higher. hope that is of some help.
Reply
Old Mar 9, 2003 | 09:43 AM
  #13  
darms's Avatar
darms
Scooby Regular
iTrader: (5)
 
Joined: Jan 2001
Posts: 2,614
Likes: 1
From: Jedi
Arrow

Why not try

http://www.scoobynet.co.uk/bbs/threa...hreadID=181616

Reply
Old Apr 3, 2003 | 08:44 PM
  #14  
SCOSaltire's Avatar
SCOSaltire
Scooby Regular
 
Joined: Mar 2001
Posts: 1,809
Likes: 0
Talking


that was cleverly funny kenny

[Edited by SCOSaltire - 3/4/2003 9:49:49 PM]
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
SilverM3
ScoobyNet General
8
Feb 24, 2021 01:03 PM
Mattybr5@MB Developments
Full Cars Breaking For Spares
28
Dec 28, 2015 11:07 PM
dovey963
ScoobyNet General
0
Sep 28, 2015 08:20 PM
RS_Matt
Lighting and Other Electrical
8
Sep 28, 2015 12:08 PM




All times are GMT +1. The time now is 09:17 AM.