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blowing bulbs- revisited !

Discussion in 'Electronic Basics' started by Andy C, Apr 1, 2007.

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  1. Andy C

    Andy C Guest

    i *might* have double posted this - apologies if so...

    hi all,
    please could anyone who is bored enough have a look at these 2 wiring
    diagrams for me...
    they are both for the same motorbike, but one is an old one and the other
    one is a later (factory modified) one...
    the older one is prone to blowing headlight and tail-light bulbs (even LED
    ones) but the newer one is much better...
    the main difference seems to be that in the later one the 4-wire regulator
    has been replaced with a 5-wire one and a bleed resistor added which is used
    only when the lights are off...presumably to help protect the regulator by
    ensuring there is always a load on it...
    i'm not 100% certain that this is the only reason the bulbs are blowing on
    the older bikes (e.g. the older ones might have crapper batteries for
    example)... but if this is the reason... why would the 5-wire regulator be
    the better system ?
    if you look at the extra (black) wire on the 5-wire regulator it simply
    joins directly with the red wire anyway if you follow the circuit (so long
    as the ignition is on).. so what is the point of the extra wire... is the
    different regulator probably not the solution ?
    both regulators charge the battery at peak ~14.8volts on a long run using
    the system for measuring peak voltage which someone previously suggested on
    this group -
    many thanks !
  2. john jardine

    john jardine Guest

    The old one blew bulbs 'cos of the crappy regulator. The makers knew this so
    they fitted a better regulator c/w bleed resistor.
    The improvement lies with the new regulator alone and not minor wiring
    The answer lies with the new regulator internals.
  3. Andy C

    Andy C Guest

    thanks, but why might the regulator have 5 wires? i can't see what the extra
    wire is (or could be in another application) doing
  4. Andy C

    Andy C Guest

    in that case... what makes a crappy regulator a crappy regulator ? both
    regulators (old and new) charge at 14.8volts and never exceed this peak....
    the output is 'smoothed' by a battery... so what could a regulator do to
    make the bulbs blow ?
  5. Jamie

    Jamie Guest

    it's simple.. it's what you call poor connections.
    Poorly designed branch circuits can cause problems where for example,
    instead of the bike making it's connection directly from the battery
    post to the ignition switch system and from there to the electrical. It
    may connect higher on the legs closer to where the alternator output
    regulator is connected. If the leg from that point going back to the
    battery for charging purposes has a loose connection. Higher voltages
    will appear because the regulator responds too fast in forcing more
    output between the phases.
    It's very possible that the regulator has a modular system where it is
    required to be plugged in to complete the circuit and if the connection
    becomes bad inside! for example a bad solder joint on the board, you
    can have problems like this.
  6. Andy C

    Andy C Guest

    ok i understand that,
    but if you look at the diagrams you'll see that this isn't the case... and
    the wiring is indeed virtually identical on both model releases of the bikes
    our prime suspect at the moment is that the earlier model has a far inferior
    battery fitted -
    my feeling is that it could well be possible to exclude the change of
    regulator as being the solution from the given information ?
    but i would be interested in any thoughts on this
  7. ehsjr

    ehsjr Guest

    Since this was answered the last time you posted it,
    I'll add my solution.

    Install the new regulator. It *must* be broken in
    after installation. To do that, put the motorbike in
    reverse, and ride for a mile. This works best on
    April 1.

  8. Andy C

    Andy C Guest

    last time we didn't know that the regulator has been modified on the ones
    which don't blow bulbs -
    are you saying therefore this is irrelevant?
    yeah thanks, :)
  9. My thoughts are that the new regulator works differently in that it does not
    rely on the battery internal resistance to control the charge current. So
    if the battery is getting old and its resistance is increasing, then you
    will get a higher voltage spike till the battery catches up in a sense. :)
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