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BATTERY DRAINING *** PLEASE HELP ***

Discussion in 'A3/S3/Sportback (8P Chassis)' started by blodderz, Feb 15, 2014.

  1. blodderz
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    blodderz Member

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    [Feb 15, 2014]
    Hello,

    Last weekend I change the rear disks and pads on my a3 2.0 tdi, finished the job went to start the car and the battery was flat (had only used the car 2hours earlier) anyway charged the battery up and was fine, then the following morning I went to start the car and again battery flat, I took the battery to get checked and the garage said it only had a 50% start capacity and that I would need a new battery. So popped to my local auto parts store and picked up a new battery, fitted then and good as new until the next day when I went out to the car and the battery is flat AGAIN!

    So this time I jump start the car and manage to get to my local garage in which he advises me that the alternator is dead and I need a new one, so got it booked straight in for a new alternator and good as new. 2hours later I go out start the car, it starts fine then I ran back in the house as Id forgotten a few things, came back out to the car and an orange battery symbol is in the central display on the onboard computer, then my lights on the dash went out and then the car died.

    Since then I haven't been able to start the car, I can jump start it but it will only last 10-15mins before dying again.

    PLEASE SOMEBODY HELP ME :((((((
    #1
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    [Sep 18, 2014]

  3. Flexiblemouse
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    Flexiblemouse Member

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    [Feb 15, 2014]
    Given that the alternator and battery have both been replaced, it sounds like the problem must be somewhere in the connection between them, sounds like something has shaken loose or broken in the charging circuit. If you use a multimeter to read the battery voltage it should read more than 14 when running. If the car is running and you read less than that, you need to start checking the electrical connection around the alternator and battery.
    #2
  4. blodderz
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    blodderz Member

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    [Feb 15, 2014]
    Thank you very much for your quick reply. My old alternator was reading 0 hence getting the new one fitted, after the new alternator was fitted the bloke at the garage said it was still only reading 8, I thought this was strange so tested it myself when I got home and it was reading 12.6 but a hour after using it the battery was completely flat again.
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  5. blodderz
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    blodderz Member

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    [Feb 15, 2014]
    Ok so Ive just been outside and jump started it, pulled some fuses to see if anything was causing a drain but nothing changed. reading from the battery when it first started up was 12.6 this then slowly dropped to 10 the longer the car was running. Eventually the orange battery symbol appeared on the dash again and the car died, tried to start it back up again and all I get is a clicking noise over and over.
    #4
  6. SmithyAG
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    SmithyAG Active Member

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    [Feb 15, 2014]
    As flexiblemouse has said, it sounds like its something stopping the alternator charging the battery, as opposed to a drain on it. If it was just something draining it then it wouldn't happen whilst it was running, (unless you have something pulling more amps from the battery than the alternator can supply - unlikely).

    I'd start checking the connections between the two, check grounding straps for corrosion, check condition of the cables between the alt and battery, and from battery to body/chassis etc
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  7. XFi
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    XFi Member

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    [Feb 15, 2014]
    Sounds like the garage haven't fitted the alternater correctly. Surely they'd investigate the fact it should be putting out 14v when running. Sounds like an earth strap or positive connection isn't even connected.
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  8. blodderz
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    blodderz Member

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    [Feb 15, 2014]
    Will take it back to the garage monday morning and have it checked.
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  9. SmithyAG
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    SmithyAG Active Member

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    [Feb 15, 2014]
    I wouldn't be so quick to take it back to the same garage who fitted the alternator and then noticed it only reading 8v and not investigating tbh.

    It shouldn't be too hard to look at yourself if you're that way inclined. If not, where abouts in the country are you? Somebody may be able to recommend a garage/help you out.
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  10. blodderz
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    blodderz Member

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    [Feb 15, 2014]
    No i was going to take it to a garage thats just around the corner from my house. But if someone was able to describe the steps to checking it myself Im sure I wouldn't have a problem checking it, I really could do with my car today so Im willing to do anything to getting it running!

    Im located in Hartlepool, north east england.
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  11. blodderz
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    blodderz Member

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    [Feb 15, 2014]
    Forgot to say I've disconnected the battery and cleaned both + and - cables and fully tightened them with still no look so guess the next step is to check the wiring on the alternator so if someone could talk me through it step by step that would be great!!
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  12. SmithyAG
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    SmithyAG Active Member

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    [Feb 15, 2014]
    What engine code is it? Can be found on a sticker in the spare wheel well or the front of the service book, or on a sticker on the timing belt cover.
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  13. blodderz
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    blodderz Member

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    [Feb 15, 2014]
    BKD mate. 2005 A3 2.0 TDI DSG.
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  14. SmithyAG
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    SmithyAG Active Member

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    [Feb 15, 2014]
    Gimme a couple of minutes to go look at mine (same engine), to make sure I've got my facts straight!
    #13
  15. blodderz
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    blodderz Member

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    [Feb 15, 2014]
    Brilliant cheers mate.
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  16. SmithyAG
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    SmithyAG Active Member

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    [Feb 15, 2014]
    Ok, without dismantling my own, it appears you need to remove the air filter and box. Not really hard, 8 screws out, separate air box from MAF housing, air filter out, then iirc theres a bolt or two in the bottom of the air box housing, and it then pulls off 2 rubber studs.

    This will give you a better view of the cables that run around that area. If you look at the positive terminal of the battery, there is a lead that goes to the fuse box (red) and a thick black one that runs down under the air box and to the alternator. Check the condition of the black cable, including where it is attached to the battery terminal grip. It should be fairly obvious if it is broken/not connected anywhere.

    Next you can remove the battery and undo the bolts on the bottom of the battery tray and remove it. Which will expose a number of earth straps, check they are all intact and free from corrosion.

    I'm just looking for some diagrams to try and help you, pictures may be better than words lol.
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  17. blodderz
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    blodderz Member

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    [Feb 15, 2014]
    Just got back inside after removing the air box and battery & battery cover but non of the wiring anywhere was corroded or damaged in anyway!
    #16
  18. SmithyAG
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    SmithyAG Active Member

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    [Feb 15, 2014]
    Have you checked at the alternator end, that you have 2 cables and a little electrical connector all connected?
    #17
  19. blodderz
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    blodderz Member

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    [Feb 15, 2014]
    there isn't a lot of room around the alternator to get a good look. I can see a black plug with black wires coming out and thats connected correctly but I'm unsure about the other one.
    #18
  20. Flexiblemouse
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    Flexiblemouse Member

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    [Feb 15, 2014]
    From my Haynes manual, hope it helps.

    If the alternator output is suspect even though the warning light functions correctly, the regulated voltage may be checked as follows.

    5*Connect a*voltmeter*across the battery terminals, and start the engine.

    6*Increase the engine speed until the*voltmeter*reading remains steady; the reading should be approximately 12 to 13 volts, and no more than 14 volts.

    7*Switch on as many electrical accessories (eg, the headlights, heated rear window and heater blower) as possible, and check that the alternator maintains the regulated voltage at around 13 to 14 volts.

    8*If the regulated voltage is not as stated, this may be due to worn brushes, weak brush springs, a faulty*voltage regulator, a faulty diode, a severed phase winding or worn or damaged slip-rings. The brushes and slip-rings may be checked (see*Section 6*), but if the fault persists, the alternator should be renewed or taken to an auto-electrician.
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  21. blodderz
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    blodderz Member

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    [Feb 15, 2014]

    Thanks for your reply, only thing is the alternator is brand new, only fitted yesterday, unless there is a chance that the new alternator is faulty?
    #20
  22. Flexiblemouse
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    Flexiblemouse Member

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    [Feb 15, 2014]
    9*To check for an open-circuit, connect one lead of a circuit tester or*voltmeter*to either the negative batteryterminal*or a known good earth.

    10*Connect the other lead to a connector in the circuit being tested, preferably nearest to the battery or fuse.

    11*Switch on the circuit, bearing in mind that some circuits are live only when the ignition switch is moved to a particular position.

    12*If voltage is present (indicated either by the tester bulb lighting or a*voltmeter*reading, as applicable), this means that the section of the circuit between the relevant connector and the battery is problem-free.

    13*Continue to check the remainder of the circuit in the same fashion.

    14*When a point is reached at which no voltage is present, the problem must lie between that point and the previous test point with voltage. Most problems can be traced to a broken, corroded or loose connection.
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  23. blodderz
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    blodderz Member

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    [Feb 15, 2014]

    Step 10, where is this referring I connect the other end of the voltmeter too?
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  24. Flexiblemouse
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    Flexiblemouse Member

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    [Feb 15, 2014]
    To the electrical connection to and from the alternator, there's definitely a fault somewhere in there
    #23
  25. blodderz
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    blodderz Member

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    [Feb 15, 2014]
    Sorry if I sound dumb, but where exactly on the alternator? The only thing I've checked so far is between the positive and negative on the battery display between 10-12v.
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  26. SmithyAG
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    SmithyAG Active Member

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    [Feb 15, 2014]
    It's further back towards the engine I believe, hidden from view by EGR and intake gubbins.
    #25
  27. Flexiblemouse
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    Flexiblemouse Member

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    [Feb 15, 2014]
    The voltage at the battery will show 12v after you jump start it, but the ignition system will flatten the battery quickly because the alternator is not charging the battery, so we know the problem is between the alternator and battery. We know the alternator is probably good and working as it is new, but it is not connected to the battery, you have an open circuit. The manual instructs you to connect the multimeter to either the negative terminal of the battery or a known good earth. Then use the positive probe to test the connections for continuity backwards from the battery to the alternator, refer to point 14.
    #26
  28. Geraldy212
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    Geraldy212 Sportback owner

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    [Feb 16, 2014]
    It is hard to imagine any single component that could drain the battery so quickly. Except perhaps the alternator itself. My idea would be to charge the battery, disconnect the alternator, make sure all lights/radio/etc are off, start the engine. Monitor battery voltage.
    If this works (the engine runs OK and battery does not die), then I would suspect that the alternator is wired backwards...ie draining instead of charging. Just an idea.
    #27
  29. blodderz
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    blodderz Member

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    [Feb 16, 2014]
    Thanks for all the replies, all sorted now.

    In the end it was all down to a earth wire that wires into the bottom of the fuse box in the engine bay, this had corroded and wasn't making contact, simply replace the wire and good as new. Only thing now is I've paid £300 for a new battery, alternator and fitting when neither of these was the problem :(
    #28
  30. hendry10
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    hendry10 Member

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    [Feb 16, 2014]
    Gotta luv the audi forum help:icon_thumright:
    #29
  31. blodderz
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    blodderz Member

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    [Feb 16, 2014]
    Yep! Only thing now is do I risk taking the brand new alternator off and putting the old one on and getting £170 back!
    #30
  32. hendry10
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    hendry10 Member

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    [Feb 16, 2014]
    I'd be inclined to leave it, unless you're desperate for your £170
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