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Parking lights

Discussion in 'A3/S3/Sportback (8P Chassis)' started by Nickl, Feb 2, 2009.

  1. Nickl
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    Nickl Member

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    Anyone know how long you have to leave your parking lights on to drain the battery? If i leave them on all night should it be ok?
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  2. Khufu
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    Khufu Active Member

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    I'd say it will flatten the battery overnight, especially at this time of year.
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  3. chill14
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    chill14 Newbie

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    In theory you could but I wouldn't want to risk it. Not in the current weather as it will affect battery levels etc.

    However if I have done my maths right then in the summer or in a warmer climate I think you'd be ok.

    e.g.

    If you are just using one side for parking lights, either left or right you are only powering two 5W (Watt) bulbs. (1 x sidelight and 1 x tail light) Total 10W.

    using formula Watts=Volts*Amps you would get the 10W = 12v * A.
    To find A you divide 10/12.

    10/12 = 0.83 Amps

    A typical battery on an A3 2.0 Diesel is 85 AmpHours (85Ah) (my new one is anyway), which in theory means it could supply 1 Amp for 85 hours, however I doubt you'd get near the 85 hours before the battery gave up.

    So if you were to leave one set of parking lights on for 8 hours, it would use 6.64 Amp Hours (Ah)

    Again in theory you would be ok with this.

    If however you were to leave you full sidelights on. ie both front, both rear, and number plate bulbs that is 30Watts in total.

    2 x front (10w), 2x rear (10W), 2x number plate (10w)

    30/12 = 2.5 Amps (rounded) * 8 hours = 20 Ah.

    This I think would start to give you problems as it would use nearly quarter of your battery's power in that time just to run your lights.

    Obviously though using either amount of power would reduce the cold cranking power available for starting the engine in the morning.

    As I said above I think I have got my maths right for this. If I haven't please correct me.
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  4. h5djr
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    h5djr Well-Known Member

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    You could leave just the two outside lights on (by setting the indicator switch before turning off the ignition) and that would only use half the battery power.
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  5. leighharris
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    leighharris Member

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    Those ARE the parking lights
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  6. h5djr
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    h5djr Well-Known Member

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    They are two of the 'parking lights'. All four lights are also 'parking lights'.

    I always park with all four parkings lights on, not just the outside two. Makes the car more obvious as a car.
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  7. Nickl
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    Nickl Member

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    thanks for all the replies guys, decided not to risk it in the end, only just found out the car had parking lights!
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  8. Steuart64
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    Steuart64 New Member

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    I cant remember reading about this in the manual but I had a strange occurrance this morning.

    The DIS came on, stating the offside rear brake light is faulty. I was turning into a parking space and went to the shop. When I came out the front nearside sidelight was on (offside was off) and when I opened the door the lights on warning was sounding. I had my light switch to auto.

    Had I inadvertantly switched on these parking lights?

    Cheers
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  9. ST09
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    ST09 ``!!$al ---

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    You must have left your indicator on .. Next time you indicate to park or etc.. Just make sure before you switch off the ignition and leave the car the indicator arm is in the middle position :thumbsup:

    Sal
    Last edited: Jul 30, 2009
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