No announcement yet.

Alternator not charging battery

  • Filter
  • Time
  • Show
Clear All
new posts

  • [Corsa D 2006-2014] Alternator not charging battery

    Hi all I have a 09 reg 1.3 cdti and having issues with the battery not charging. I have replaced the alternator and still having the same issue. New battery has been fitted as well. When I use meter to get reading from battery and alternator there is a reading of 12.4 when not running on battery and when started drops down to 11.4. I have tried to get reading from alternator but it saying there is nothing coming out 0 volts? Any ideas?

  • #2
    Hi Welcome to the forum . You should be getting about 14 volts at the battery, with the car running. Are you sure you've fitted the right Amps Alternator to the car. There are three different types,  70amps, 100 Amps, 120 amps . I did this myself once and fitted a 70amps ,when it should have been a 120 Amps . And I can't remember,  but one of them has a built in Regulator.  If you still have the old Alternator have a look on the plastic cover it should say the amps on it .


    • #3
      Yes new alternator same as the old.  Got a question. See the wire that goes on the b+ post should that have power to it? When I disconnect this at the alternator and try to get a reading from the wire itself it says zero volts with or without ignition on. From my experience this should have the power coming from the battery??


      • #4
        The B+ terminal is Normally the large red wire from the Battery. If you try and disconnect it with the battery connected you will probably get sparks. The small wire sends 12volts when the car is running back to the red light on the Dash. Can you get under the car and check the wires on the back of the Alternator. Red prob on the large red wire and the earth on a good earth on the engine block. Should be 12volts without the ignition on or the car running. If not you've got a break in the wire or a bad connection. 


        • #5
          If you can rig up a 'test light' - a 12v bulb with wires attached - you could try disconnecting the thin wire at a the back of the alternator, connecting one of the test light wires to the alternator small terminal and the other test light wire to battery positive (It is possible to use just a wire without the bulb, but safer to have the bulb in place)
          Providing that (a) The alternator is in good order and (b) The thick wire from the alternator to battery positive is intact with clean, tight connections, then when the engine is running, you should get about 14 Volts at the battery.

          If there is zero Volts between that thin alternator wire and earth with the ignition switched 'ON' then there is a fault in the wire, its connections, or control

          Don't try running the engine with the output (thick) wire disconnected from the alternator or battery.