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Alternator Charging Problem?
MakeEverything - 21/10/11 at 11:40 AM

Hi all,

The last job to fix (well, it was until i spotted one of the coolant hoses too short!) is the alternator and charging problem ive got.

  • Ive had the alternator tested, and they said it was ok.
  • The charging light comes on, and stays on when the car is running (as expected due to not charging)
  • The battery is an Odyssey PC680 which does go flat quite quick and i may have damaged it by charging it over and over whilst testing.
  • All the wiring is correct, and i have a live feed direct to the battery from the charging post, and have even put in a separate ground from the alternator to the battery.
  • The switched live at the plug is also ok and stays live when the car is running.
    Battery Charged, i get 12.8V. When started, i get 12.8V. When the car has been running for a bit, i still get 12.8V but this drops when i turn the car off.

    The only other (Most expensive) solution is to change the battery. HAs anyone experienced these symptoms and successfully diagnosed the battery before? Just need to check before buying a new battery.

    [Edited on 21-10-11 by MakeEverything]

    steve m - 21/10/11 at 11:50 AM

    Is the 12.8v with a multi meter. across the battery with the engine running?

    Is the warning light wired up correctly? ie lead from alternator to dash bulb, the bulb to ignition ON LIVE

    if its not, then you will not be charging

    Steve

    MakeEverything - 21/10/11 at 11:55 AM

    quote:
    Originally posted by steve m
    Is the 12.8v with a multi meter. across the battery with the engine running?

    Is the warning light wired up correctly? ie lead from alternator to dash bulb, the bulb to ignition ON LIVE

    if its not, then you will not be charging

    Steve


    Yes and Yes.

    The warning lamp and ignition leads are correct.
    The 12.8 is across the battery, on the MS2 and from a flying accessory lead that i have in the engine bay for the nitrous controller.

    scudderfish - 21/10/11 at 12:38 PM

    What alternator is it? Can you post a pic of the connections?


    It's not French is it?

    britishtrident - 21/10/11 at 12:57 PM

    Thinking out of the box Is the warning lamp the correct wattage ? The warning light has to pass enough current to energise the windings, an LED won't pass anything like enough current.

    MakeEverything - 21/10/11 at 06:37 PM

    quote:
    Originally posted by britishtrident
    Thinking out of the box Is the warning lamp the correct wattage ? The warning light has to pass enough current to energise the windings, an LED won't pass anything like enough current.


    The warning light circuit is exactly as was when it worked previously, with the same alternator.