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LED

Discussion in 'The Garage' started by inxs, Dec 8, 2009.

  1. inxs

    inxs xx

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    - as usual what you take from this will simply be a figment of your imagination…im an xspurt not an xspert…once upon a time I was the top of my swimming class, that was about when my advantages stopped…

    What are LED’s ?

    [​IMG]

    - small semi-conductor diodes-diodes conduct electric current in only one direction
    - can be used as relief valves, rectifiers to convert ac to dc or modulators eg radio waves
    - P-N junction design exploits non-linear electrical properties for specific uses, zener diodes for voltage regulation, varactor diodes for radio and tv tuning, tunnel diodes generate rf waves and LEDs emit light…recombination of N-type e- with P-type holes causes emission of photons or light
    P-positive side, holes or empty electron sites
    N-negative side, free electrons

    [​IMG] [​IMG]
    [​IMG] [​IMG]

    - -zero and overlapping bandgaps are conductors
    - -small bandgaps are semi-conductors…less than 3-4eV
    - -large bandgaps are insulators

    [​IMG]

    - Critical factors…band gap, electron mobility-conductance


    Band gap…energy required to free an electron so it can pass between the outer valence shell and conductance bands-discrete electron activity probability zones

    [​IMG]

    - depends on the material..LED’s are usually AluminiumGalliumArsenide, AlGaNitride
    - depends on pressure-
    direct ... valence band max energy equals conductance band min energy
    indirect … these are not equal eg. silicone…emit heat, not used for LED’s

    [​IMG] [​IMG]

    - depends on crystalline stucture
    - decreases with increasing temperature
    - controlled via semi-conductor alloy composition, doping GaAs GaN or layering
    - absorbs or emits heat, phonon and or light, photon


    In direct band-gap semiconductor diodes, eg. gallium arsenide, junction crossing n e- emit photons when recombining on the p side, producing, dependant on material, wavelengths (or colours) from infrared to near ultraviolet. Diode forward potential corresponds to the emitted photons desired wavelength: 1.2 V corresponds to red, 2.4 V to violet. Originally LEDs were red and yellow, higher-frequency diodes being later developed. All LEDs produce incoherent, narrow-spectrum light; “white” LEDs are actually combinations of three LEDs of a different color, or a blue LED with a yellow scintillator-phosphorous coating.

    [​IMG]

    LED’s gained use for low power indicator applications eg. a green and red 5mm LED’s as switching reminders. Future LED technology will include… OLED’s, nanotech...

    [​IMG]

    [​IMG]

    Currently, benefits are most seen in low voltage ( 12 to 24 volt DC) automotive, marine and alternative power applications. Advances will attain higher levels of illumination, with high power LED lights replacing fluorescent, incandescent, and halogen light bulbs.

    The key is understanding LED power and cost efficiencies.

    Power efficiency allows comparison of various lighting systems, "lumens per watt" indicates total luminous output, compared to overall power dissipation.

    Cost efficiency, "lumens per dollar", indicates luminous output, compared to actual manufacturing costs.

    Although LED circuits can provide energy efficiencies equal to or better than most traditional light sources, high production costs offset energy efficiency. Savings only occur long-term.
    .
    Unlike incandescent light bulbs LED’s require thermal management. Heat produced during LED operation transfers downward into the circuit board. Design must dissipate this away from the LED.

    LED drivers

    LED bulbs are often driven using series resistance, this works okay so long as no external loads are applied eg. compressor, pump, headlight…immediately decreases both current and voltage, seriously affecting LED lifetime.
    Due to low start-up demand, LED bulbs are extremely sensitive to current and voltage spikes. Low battery voltages increase resistance causing heat, high voltages risk premature failure or dimming by overdriving the LED.
    Constant current LED’s incorporate small integrated circuits sensing any voltage variations, automatically compensating for losses.

    Miniscule chemical substrate variations can cause fluctuations in current demand.
    Temperature is also a problem. As temperature increases with current, improper current regulation can cause voltage to rise leading to early failure.

    What does this mean for XS650’s

    That’s going to depend on what you have done to your bike…oem alternators and charging systems will love you. LED’s decrease power demand considerably, taking a load off the battery and charging system. Those, like me, who run a PM system have the opposite problem-what to do with all the xs power.

    Most will think about installing LED indicators, some will consider replacing the tail, brake and number plate lights. Some will replace the headlight. My SR has LED dial lights and highbeam, neutral and blinker warning lamps.

    If youre into design, build your own custom lights to fit any available space. Internally wired and set individually into the frame. I could envision future uses of OLED-Organic LED-surface coating applications for some pretty futuristic colour and lighting effects

    LEDs require direct current DC with low voltage, not the AC supplied by our alternators.

    Functioning rec-regs are required, the rectifier to to convert AC to DC , the regulator to maintain a constant voltage as are a battery or capacitor for power supply smoothing.

    Voltage control is important. As current is approximately an exponential function of voltage, small voltage changes result in large changes in current
    Voltage below the threshold, on-voltage, produces no current, no current – no light. High voltage pushes current above the maximum rating, overdriving and heating LEDs. As they heat, voltage drop decreases with band gap, further increasing current.

    Series or Parallel

    Connect LEDs directly to constant-voltage sources with either, Series resistors, simple but wastes energy as heat, or, a constant current regulator commonly used for high power LEDs. Low drop-out (LDO) constant current regulators improve efficiency and reduce power use

    Miniature indicator LEDs are normally driven from low voltage DC via a current limiting resistor. Currents of 2 mA, 10 mA and 20 mA are common. Sub-mA indicators may be made by driving ultrabright LEDs at very low current. Although efficiency is reduced at low currents, running 100μA indicators is still practical.

    Operate LED strings in series. Total LED voltage should be around two-thirds the supply voltage, each string being resistor current controlled.
    A single series string minimizes dropper losses, while paralleled strings increase reliability. In practice usually three strings or more are used. Using a capacitor can reduce high line voltage without wasting power, with a very simple circuit; there may be a short high current surge upon start-up.

    Parallel operation is also possible but can be more problematic. Branch currents must be equal, Parallel LEDs must have closely matched forward voltages (Vf) for equal light output. Variations in the manufacturing process add to the challenge.

    Some LEDs have built in series resistors, saves PCB space, and are useful when building prototypes or custom PCBs. Resistor value is set when manufactured, blocking a key method for setting LED intensity. Seven-segment and starburst LED arrays are available in both common-anode and common-cathode form.

    resistor calculator

    The formula to calculate the correct resistance to use is:

    {power supply voltage} (V_s) - {LED voltage drop} (V_f) = {resistance in ohms} (R)
    ------------------------------------------------------
    {LED current rating}(I_f)

    where:

    * Power supply voltage (Vs) is the voltage of the power supply e.g. a 9 volt battery.
    * LED voltage drop (Vf) is the voltage drop across the LED (typically about 1.8 - 3.3 volts; this varies by the color of the LED) 1.8 volts for red and its gets higher as the spectrum increases to 3.3 volts for blue.
    * LED current rating (If) is the manufacturer rating of the LED (usually given in milliamperes such as 20 mA)

    http://www.hebeiltd.com.cn/?p=zz.led.resistor.calculator


    http://www.webbikeworld.com/lights/
    http://www.customdynamics.com/pdf/Cust_Dyn_Catalog.pdf
    http://www.radiantz.com/cart/index1.html?c34.html&1

    home build…
    http://www.maushammer.com/systems/tail-light/index.html

    headlight…
    http://ecomodder.com/forum/showthread.php/led-headlight-6514.html
    http://www.instructables.com/id/LED_Motorcycle_Headlight/

    LED light…
    http://www.ehow.com/how_4727328_build-led-motorcycle-light.html

    taillight…
    http://blog.makezine.com/archive/2008/02/led_motorcycle_tail_light.html
     
  2. inxs

    inxs xx

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    - some reading

    LED Lighting

    Multistrada LED Brake Light Installation
    http://www.webbikeworld.com/ducati-motorcycles/multistrada-620/led-brake-light/

    Hyper-Strips LED Accent lights can really show off your bike!
    http://www.webbikeworld.com/r3/led-light-motorcycle/

    LED brake light or tail light complete conversion to replace the bulb with LED lights for ultra-visibility!
    http://www.webbikeworld.com/t2/motorcycle-led-light/led-brake-light.htm

    LED Bulb Replacement by LEDTronics: is it worth the cost?
    http://www.webbikeworld.com/Motorcycle-technical-articles/led/

    LED Brake Light Bar by Signal Dynamics: installation information.
    http://www.webbikeworld.com/Motorcycle-technical-articles/led2/

    Flexible LED accent lights can be installed as auxiliary directionals or just for fun!
    http://www.webbikeworld.com/lights/motorcycle-led-light/led-light.htm

    Super-Bright LED brake light bulb LED cluster can replace the standard 1157 brake/tail light bulb.
    http://www.webbikeworld.com/r2/led/led.htm

    RiderLight LED Wireless brake light for helmets, saddlebags and more!
    http://www.webbikeworld.com/r2/riderlight/

    LED Wireless helmet brake light - the Signalfly unit fits on the back of a helmet!
    http://www.webbikeworld.com/Reviewed-motorcycle-products/signalfly/
     
  3. Holy shit inxs! Now I fully understand your username. You definitely do everything inxs. But we appreciate it! When we get the Tech section going, it’s going to be mostly your content. :D
     
  4. inxs

    inxs xx

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    - naya, im sorry for confronting people with shit they never even knew they didnt need to know...its kinda nice having the space to put it where i can see it

    - i see lots of interesting things happening with LED tech...sure, now its mostly low power blinkers, stop - tail lights and deco but soon LED's will be everywhere, we will see legal headlights, jackets with LED fibre woven into them or LED panels sewn into them ... helmets fairings tanks and panels coated in LED coatings...wireless, remote controlled...

    - its likely to become the predominant interior-exterior lighting technology

    - no, its not going away...i just figure may as well learn something about it, theres fun to be had doing things here...
     
  5. crash

    crash XS650 Junkie

    thanks for the great info on the led lights.:thumbsup:
     
    Hightower-Ash98 likes this.
  6. Precisely put.....but with gratitude! Blue
     
  7. curt698

    curt698 XS650 Addict

    I'm most intrigued with the Radianz clusters because of the ease of instillation. I am asuming that just because they can fit in a signal or tail as a direct replacement a resitor would still need to be added somehow?
     
  8. inxs

    inxs xx

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    - some of these are designed with internal resistance, i have no personal experience with this product, however, when in doubt contact them direct before you buy, there is no such thing as a dumb or stupid question... sales@radiantz.com

    - please post your result :thumbsup:
     
  9. angus67

    angus67 Welder's penetrate deeper!!

    so... it all never answers MY question.....What is the purpose of the flat spot in the first diagram?
     
  10. inxs

    inxs xx

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    - flat spot, by the -ve electrode, is another design feature helping users not to get the polarity wrong, same as the longer +ve electrode
     
  11. weekendrider

    weekendrider Iron Horse cowboy Top Contributor

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    curt698, I'm not sure about the brand, but a friend tried the bulbs and you couldn't see them in the daylight very well.

    I'm not sure about what all those graphs and charts say, but with a led truck tail/stop light, hacksaw, soldering iron, and some silicone, you can get a really bright light for around $14-16
     

    Attached Files:

  12. Backroader

    Backroader XS650 Addict

    This might take me a little while to committ to memory.....I hope there isn't a test on this in the morning.
     
  13. inxs

    inxs xx

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    - interesting suggestion found on clays motorcycles for replacing original bulbs with LEDs
     
  14. As a customer testimonial, the light reviewed in this article is entirely amazing. The only downside is that i had to take the bulb out of my "your tail light is out blink/brake light is working" indicator on the console. I'll try to figure out how to make that work again, but it relies on the load in the bulb, which is negligible now.

    from: http://www.customdynamics.com/
    Item # Name QTY Price Total
    GEN-20-R-1157 Genesis 2.0" Direct Base Red 1157 1 34.99 34.99
     
  15. I am going to be running a LED tail light! Picked up one that MSRP's for like $150 or so for $15. I think it was off of a wrecked bike, but it works and I just painted it black anyway. Can't really tell.

    In case anyone was wondering. Here's the light I'm going to be running. Except rattle canned black.

    Light
     
    Last edited: Feb 25, 2010
  16. cheftay

    cheftay Keepin' it real

    Nice work! That was my original purpose when i opened up this thread but then I got sidetracked :oops:
     
  17. SWB_Chev

    SWB_Chev XS650 New Member

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    Check out SpeedWaymotors.com, as they offer a 7 inch LED headlight. Deffinately not cheap at $289.99 each, but would be unique at least for the time being. Should have a very low wattage draw. What do you guys think about them?
     
  18. Two Wheel Mafia

    Two Wheel Mafia www.twowheelmafia.com

    I used LED's to build a custom tail light... LED's are the cool new way to go.
     

    Attached Files:

  19. Bandito

    Bandito Twistin' the Throttle

    I purchased some bullet style LED turn signals for my XS650.

    I replaced the stock yamaha flasher relay with a Grote Industries variable load
    electronic led flasher.

    http://grote.com/product.php?product_number=44891

    It is a 3 prong setup with an external ground, which I connected to where
    the coil attaches to the frame.

    With a battery at 12.7v and over, I turn the ignition on, you can hear the
    relay activate.

    But none of my turn signals work...

    Am I missing something here?

    The only wiring that I am aware of regarding the lights is the ground for each
    signal and the power lead for each signal.

    Where am I going wrong? Any ideas?
     
  20. forkmech13

    forkmech13 XS650 New Member

    Try removing the flasher indicator bulb in the center cluster it maybe causing some feed back.
    Now I believe your flashers will work.

    I removed the cluster between the gauges all together and placed a small LED in each of the cluster mounting holes and wired one to the right turn and the other to the left.
    I used the GROTE 44010 solid state electronic flasher.
    Red LED's from The Source (radio Shack) 276-0011
     

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