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Alternator or Battery?

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

  1. SunnyG
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    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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  2. jb0o
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    jb0o North East Forum Moderator Regional Rep Site Sponsor

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    Sounds like battery isnt holding its charge.
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  3. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    stick a voltmeter across the battery with the engine off, and again with the engine running.
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  4. SunnyG
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    SunnyG Member

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

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    13.9 or above when running
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  6. SunnyG
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    SunnyG Member

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    So if its below it means? sorry about being such a noob
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  7. Ste_Nova
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    Ste_Nova Active Member

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    alt not providing charge
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  8. SunnyG
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    SunnyG Member

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    okay thanks so if i see 13.9+ its the battery for sure?
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  9. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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

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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.
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  12. SunnyG
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    SunnyG Member

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    thanks for all the help
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  13. Squirrelofdoom
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    Squirrelofdoom Member

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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
    #13

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