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Headlights blink when I wear heated vest on motorcycle

Discussion in 'Electronic Basics' started by ImOk, Nov 1, 2005.

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  1. ImOk

    ImOk Guest

    I bought a heated vest from Gerbings which draws about 77 wats or 7amps
    of 12V power. It has this low tech thermostat that keeps turning on and
    off every second or twice a second to regulate the power that goes to
    the vest and thereby the heat. There is an LED tha blinks on and off
    that is the indicator. If you turn it up it just blinks faster until it
    goes full solid (no on/off).

    The problem is that when it is going on/off my headlights lose and then
    gain brightness. Its probably the shock or surge when the circuit is
    turned on off on and so forth repeatedly.

    What kind of circuit could I use to prevent this? I am pluggin into the
    cigarette lighter called a BMW power outlet.

    Do you think this would damage the alternator or battery if I leave it
    like this?

    This is the vest:

    This is the temp controller.

    Any ideas would be appreciated.
  2. What model of motorcycle are you riding? My BMW 1995 R1100R has a 50
    amp alternator that regulates the battery voltage very precisely, in
    spite of load changes. If you are overloading the alternator with the
    7 amp load, you must expect the voltage to fall when the heater is on
    and return to normal when it is off. But a 7 amp load would be a non
    event on my bike after a few milliseconds. Perhaps your alternator
    needs new brushes.
  3. Jasen Betts

    Jasen Betts Guest

    Low-tech solution: wire the outlet via a more direct route to to the altenator.

    hi-tech solution: dump the low tech thermostat and go with one that does
    pulse-width modulation or similar, although at 11A that'd be non-trivial
    (not a beginners project anyway)
    it's using about as much power as your headlight probably uses, so on a
    well-egineered machine like the BMW i'd say no.
  4. ImOk

    ImOk Guest

    Im riding a Triumph Bonneville America 2004. I doubt the alternator is

    But if you had something flickering on and off every second drawing 7
    amps wouldnt you be noticing it on your bike?

    Do you think a plain old variable resistor would work. Like the ones
    they have in houses for dimming lights?

  5. ImOk

    ImOk Guest

    <<Low-tech solution: wire the outlet via a more direct route to to the
    altenator. >>

    I have to look at the schematic to see how this thing is routed. But
    that may be something to try.

  6. Guest

    Yes, unlikely for such a new bike.
    I wear heated clothing all winter and have never noticed any effect.
    My vest has an electronic on off control based on temperature at one
    point in the vest, but the cycle time is in the 10s of seconds. Same
    with the gloves. My helmet heater is continuously regulated besed on
    PTC thermistor heater elements. No cycle from them. But then, my
    alternator is large enough to run 4 halogen headlights and more. BMW
    finally faced the fact that people want to add all kinds of electric
    gear to their bikes and designed in a capable alternator.
    I think you should first check up on the alternator spec. It may be
    designed for the current the bike uses, and little else. If this is
    the case, you could look into a switching regulator that converts high
    volts at low amperes into lower volts at higher amperes with an
    adjustable output voltage. That would eliminate the visible cycles and
    also reduce the current load, once the heat reached equilibrium and you
    turned the control down from maximum. But even if you just altered the
    present design (assuming it uses a mosfet switch to control the
    current, not a contact) to make the timing cycle very short (a few
    milliseconds per cycle, say, for 100 or so cycles per second) you could
    eliminate the visible flicker pretty well. The LED would appear to be
    on all the time, but with varying brightness.
  7. kell

    kell Guest

    Wire a heavy load to get its power as directly as possible from the
    battery, as when installing a headlight relay on an old car.
  8. You need a new, higher capacity battery and a more powerful regulator
    to handle the added load of your jacket. Or, you could be stoic and
    consider that you've added a headlight modulator at no extra cost.

    Ride safe.
  9. Ah. A Triumph. Did you know you can buy smoke in a jar for Triumph
    motorcycles? It's for putting back into the electrics after the
    original smoke escapes. Seriously, get the bike checked out, you
    might have a dying battery, or some other malfunction of the
    electrics. FWIW, I ride (perhaps I should say "store") a '98 Triumph
    Tiger, so I feel your pain.
  10. Wow, that's pretty stout for a motorcycle. 32A is common for a modern
    geezer glide Harley, AIUI my Sportster only has a 22A system. That's at
    max output, not what you get at idle speeds. I could see where a 7A
    load toggling on and off might be noticable.
    Hmm, brushes? I don't know how yours works, but mine has a multipole
    stator with a permanent magnet rotor that surrounds the stator sort of
    like a brake drum. That part operates in scalding hot oil. The wires
    come out of the engine and lead to an external voltage regulator that
    contains, I assume, a bridge rectifier amongst other goodies. Perhaps
    you have a generator?
  11. Jasen Betts

    Jasen Betts Guest

    variable resistors aren't used for dimming lights, and those dimmers don't
    work with DC.

  12. Many Japanese bikes and Harleys have the permanent magnet AC generator
    you describe, so the regulator has to deal with the full output current.

    The BMW has an ordinary looking automotive alternator sitting on top
    of the engine driven by a multi groove belt. Look at the alternator
    on top of any Subaru engine and you will see what it looks like. In
    fact, the two cylinder engine looks like the front two cylinders of
    the Subaru engine. The brushes connect the excitation current from
    the regulator (solid state, inside the alternator, in the case of the
    alternator) to the wound rotor through a pair of slip rings, just like
    in most modern automotive alternators. It is rated 35 amps at idle,
    50 amps maximum.

    My wife's Suzuki alternator is a permanent magnet, crank shaft mounted
    type like you describe, and it has a big, external, heat sink mounted
    regulator, that rectifies and SCR phase controls the output to the
    electrical system. It is designed such that the bike's electrical
    system just about uses all the current it produces at speed, and a bi
    less than the bike uses at idle. If this is similar to the Triumph in
    question, then, at idle, at least, the vest is bound to sag the
    battery when it comes on.
  13. quietguy

    quietguy Guest

    Haven't seen your original post, but wonder where the take off point for
    your vest is - eg if it and the lights were on a common wire, then you
    might be getting a voltage drop across that feeder.

    Perhaps as an experiment you could try attaching the vest directly to your
    battery instead of where it is now, (couple of battery clips or such) and
    see if the problem persists.

  14. Better yet, as close to the alternator output as possible. that,
    after all is where the current comes from.
  15. ImOk

    ImOk Guest

    That is my plan to try it on the battery directly. It came with its own
    battery clips, but I figured it would be easier to plug in to the power
    outlet of course.
  16. ImOk

    ImOk Guest

    I dont have any problems with the Triumph nor any pain (except from
    riding it too much and too fast). You are perhaps thinking of the old
    Lucas stuff. Long and gone.

    This machine is superb compared to similar machines out there.
    Everything works fine, including running lights, car horns, headlights.
    Even the jacket works fine at full power (always on). The problem is
    the low tech system Gerbing uses (on/off every second to control the
    temperature). 7A is a lot of power to draw on and off constantly
    without a momentary brownout.

    Anyway, the generator is rated at 27Amps. I dont think I am using all
  17. When I rode a motorbike in the UK all I had was a couple of extra pairs of
    trousers and some gloves! My helmet was a WW2 tank hat with holes all over

  18. You have my sympathy. Electric heat is lovely on a bike in winter. I
    ride all winter in the state of Virginia, except when there is snow on
    the roads (and sometimes I get caught on that).
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