Battery light on while ignition is off

Discussion in 'Fuel System & Electrics' started by columbia, Mar 21, 2010.

  1. columbia

    columbia New Member

    Messages:
    6
    Location:
    brisbane
    Good morning :)

    I am a fresh member here. It is good to finally be involved in threads, I have always been lurking, but never stepped out from under the boughs.

    So, my question goes...

    Lillian & I, '74 Type II, had an incident on the riverside expressway last week and hasn't been quite right since. I eventually got home, after discovering that when I turned the headlights on the engine stopped completely.

    The battery light stays on whilst the ignition is off, and eventually completely drains the battery.

    With a voltmeter I measured the battery after i recharged it and the battery with the engine off is right around 12V but when the engine is idling, it is around 11.

    So is it safe to assume that it is the alternator that I need to dig out and get reconditioned?

    It is a job a only partially look forward to doing :)

    Any thoughts would be fantastic
     
  2. columbia

    columbia New Member

    Messages:
    6
    Location:
    brisbane
    Oh and also, when the engine is running, the battery light gets brighter as I step on the accelerator then dims a bit when my foot is taken off. The battery light stays on though.
     
  3. kombi van dan

    kombi van dan New Member

    Messages:
    76
    Location:
    byron bay
    i to have similar problem to this story, can anyone shed any light on this?
     
  4. t4camper

    t4camper Active Member

    Messages:
    333
    Location:
    rainy Maleny
    It sounds like a voltage regulator, part of the charge system.

    Small aluminium box on the right hand back wall of the engine compartment.
    About $40. Has about 3 wires connect to it.

    It controls the battery light and as the name suggests regulates the voltage to the alternator.
    When the ignition key is turned off, the voltage regulator should release a contact and the light go out.
    A second function of voltage regulation is by controlling the level of exciter current that is supplied to the alternator, it sounds as if the exciter circuit is not opening when key turned off and that is what is draining your battery.
     
  5. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,547
    Location:
    Penna, Hobart
    I recommend making this a sticky. I haven't been able to find a decent description on checking the alternator connection any where, particularly a kombi one when it is mounted in the car.

    Adrian
     
  6. columbia

    columbia New Member

    Messages:
    6
    Location:
    brisbane
    Wow, 1500king and T4camper, thankyou so much for all the information. I will have to read through it slowly out in the driveway with head in the engine compartment and start testing later on this week. I'm going to give it a good go at diagnosing it before I take it to someone. Thanks for the help....will let you know how I go.

    t4camper, I didn't break a belt but I have a sneaking suspicion that the RACQ guy may have reversed the polarity on the battery when he tried to jumpstart the van as it was all fine up until that point. Or maybe I am paranoid.

    Thanks!!!
     
  7. SCUBA

    SCUBA New Member

    Messages:
    5
    Location:
    Toowoomba
    Dealing with Battery charge light being constantly on and battery not charging. Replaced Ignition switch, replaced Voltage Regulator - but no success. Went back to checking wires. Discovered Brown wire from alternator to the voltage regulator is burned out - insulation has all melted. I suspect this is the problem ;) Now trying to find a simple way to access the Alternator terminals without having to remove the Alternator...Might have to get a book...
     
  8. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,547
    Location:
    Penna, Hobart
    Really the only way is to take out the alternator as it runs through the rear shroud and you cant remove that while it in the bus. There is a thread with a video on removing the alternator but I have found with a bit of twisting and patience you can get it out of the bus from inside the engine bay without removing the exhaust, which seem to be the method described in most books. All you need to do is remove the engine tin and the oil filer plastic spout (fill the hole with a rag), then the tin ware in front of the alternator, push the cables down through the hole in the tinware on the side, loosen the air intake off the rear of the alternator where the air from the fan housing comes in, unbolt it at the bottom and the top, and carefully twist and turn it as you pull it out in to the engine bay.

    That said I think you may find there are more problems than just the burn wire. I would suggest there may be a short in the internal wiring. May be worth the effort to get a rebuilt one.

    Adrian
     
  9. SCUBA

    SCUBA New Member

    Messages:
    5
    Location:
    Toowoomba
    Thanks Adrian. I expect you are right. I'll check the harness for shorts once I get the alternator out. Do you have any idea what gauge the wires in the harness are? It's a 70A alternator so I expected they would be around 8AWG but they don't look thick enough. I can't find any reference to the wire size in the book. Cheers, scuba
     
  10. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,547
    Location:
    Penna, Hobart
    I don't speak in gauge as far as wire size, being a standard sparky rather an auto one, but you would need a cross sectional area of around 4mm squared for the main alternator output lead and 1-1.5 mm for the rest. Those field windings do not carry a lot of current (unless they short out). You should be able to find a converaion chart online but when you go to get the wire make sure it has a high strand count and is the right insulation for automotive work.

    Adrian
     
  11. SCUBA

    SCUBA New Member

    Messages:
    5
    Location:
    Toowoomba
    Well, I rewired everything and put it all back together- alas still no joy. Did some voltage checks and voltage drop tests - it's the alternator :( I took it to the local Auto Electrician - looks like stator stuffed and the diodes are blown. Anyone know where I can get a Bosch 70A for a 2litre 77 Bay or if there is an equivalent alternator that
     

Share This Page