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Alternator or Battery?

Discussion in 'A3/S3 Forum (8L Chassis)' started by SunnyG, Jul 15, 2012.

  1. SunnyG

    SunnyG Member

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    Hi there, just got me a PD130 A3, car has a strange issue has to be push started otherwise doesn't start can then be driven around but lets say you drive it for 20mins the car doesn't start again. Could this be battery issue or alternator?
     
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  3. jb0o

    jb0o North East Forum Moderator
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    Sounds like battery isnt holding its charge.
     
  4. aragorn

    aragorn "Stick a V8 in it!"
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    stick a voltmeter across the battery with the engine off, and again with the engine running.
     
  5. SunnyG

    SunnyG Member

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    What should I be looking for on the voltmeter? I just want to be sure to be honest.
     
  6. Ste_Nova

    Ste_Nova Active Member

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    13.9 or above when running
     
  7. SunnyG

    SunnyG Member

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    So if its below it means? sorry about being such a noob
     
  8. Ste_Nova

    Ste_Nova Active Member

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    alt not providing charge
     
  9. SunnyG

    SunnyG Member

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    okay thanks so if i see 13.9+ its the battery for sure?
     
  10. aragorn

    aragorn "Stick a V8 in it!"
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    could also be the starter, hence why i said check with the car off too
     
  11. SunnyG

    SunnyG Member

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    okay thank you but i guess if its lower than 13.9 running that eliminates the alternator? Thanks for all the help
     
  12. aragorn

    aragorn "Stick a V8 in it!"
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    if its at or above 13.9 then the alternator is fine.

    With the car off i'd expect to see 12.6v or so from a healthy battery.
     
  13. SunnyG

    SunnyG Member

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    thanks for all the help
     
  14. Squirrelofdoom

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    TO be hoenst, if your alternator was gone, you couldn't get a mile down the road before your 12V system shutting off :) I think you can safely assume your alternator is fine
     

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