led bulb type?

Discussion in 'General Questions' started by Torques, Sep 13, 2008.

  1. Torques

    Torques Guest

    I just hooked up my kpr112 bulb to the white wire. The engine does have a tendency to die when at idle (with the light on). Can anyone specifically tell me what company sells an led that should operate from the 48 cc ht motor? I hope a led might be brighter and not kill the engine. Does anyone believe the following would work:


    Thanks in advance.
    Last edited by a moderator: Sep 13, 2008

  2. fetor56

    fetor56 Guest

    I won't be specific about companies that sell them cos any half-descent electrical/electronics store will sell them.....shop around man but the internet isn't absolutely necessary in this case.
    LED's are VERY forgiving about the voltage used to power them so anything ranging from 3 volts to 24 volts should work fine.One big thing against them is that their not focused so if u don't have some system to focus them correctly the light will SPREAD-OUT & diffuse rapidly.
    I'm sure that Maglite would work good...6V & focused.Their expensive bulbs but u are getting a great deal of illumination.
    My front headlight is from a 6V/$10 torch(flashlight) & has a tight beam for 1Km.........amazingly powerful. :cool:

  3. sparky

    sparky Active Member

    Check out www.candlepowerforums.com for serious lighting concerns.

    I went there and asked them about the best LED flashlights to use with the TwoFish Lockblocks mount... and everybody consistently said the Fenix L2D Q5 was the best around... they said two of them for a low and high beam are unbeatable, and I believe them... but one flashlight is good enough for me. It doesn't have focus capabilities, but the beam is a bright white, and the spill is very wide and still pretty bright.

    For running 2+ hrs at consistently the same regulated output on only 2-AAs, being waterproof, so compact, no wiring necessary, not degrading the quality of the spark or robbing the engine of power, being able to detach and reattach the flashlight within a second or two, etc... I don't see why people still try to run a light off the white wire.

    If you understand optics and figure out how to control the beam to your liking, I'm sure we'd all love to hear your solution. But if you wanna try the L2D Q5 light with the Lockblocks mount... www.4sevens.com has an 8% discount if you use the CPF8 code at checkout. They also have free shipping to anywhere in the world.

    I tried the Coast P7, and did love it's ability to easily focus and the SUPER long battery life off of 4-AAAs... but you could nearly buy two L2D Q5s for the same price, and the Coast P7 isn't regulated, so the output consistently diminishes over time. The beam pattern is what was coolest on the P7... it was pretty large & solid all around, but there wasn't really "spill", nor was it as wide of an overall beam as the L2D Q5. You can clearly choose either one and be happy with them as flashlights and MB headlights... but two L2D Q5s would be better than just one P7 any day, and one L2D Q5 should be good enough for anybody.
  4. sparky

    sparky Active Member

    Most torches with tight beams wouldn't be optimal for MBs because of the narrow beam, but that doesn't look like a typical torch at all. Wish I could see some beamshots at night...
  5. Torques

    Torques Guest

    Thanks for your response but my question specifically is about "bulbs" not flashlights. I'm looking for a led to replace the KPR112 running off of the white wire. I can buy a led bicycle light anywhere. I have an extra one sitting here. I think I'll try the 4 cell maglite upgrade led. I hope that works and that I'm not wasting my time. The KPR112 seems to tax the mag too much and the motor tends to die at idle with the light on.
  6. DougC

    DougC Guest

    The two common LED drop-in flashlight bulbs I know of are the one from EverLED and the one from Mag-Lite. Between these two, the Ever-LED puts out a tiny bit more light, but used a bit more power as well. These cost some money, but then again, you're probably not never going to burn them out either--and even if you stop biking (during winter or whatever) you can use the bulb in any other flashlight you have.

    I don't know what current these draw but it is much less than the comparable incandescent bulb does.


    If you want to experiment with building your own LED light setup, I'd strongly suggest going somewhere that sells the LEDs and the drivers for them. You can't hook a LED right up to batteries, it has to have a regulator to keep it from oveheating and burning out (the LED drop-in bulbs have this circuit built into the base).

    Here is one such place that sells CREEs & drivers:
  7. Torques

    Torques Guest

    I just got home from looking at the maglite led's. The base it too big (bigger than the KPR112 diameter), so that's out of the question.
  8. RogerS

    RogerS Member

    Wish I could see some beamshots at night...
    A local bike shop did just that. Just click on the different bike lights and you get a picture of what its beam looks like.
  9. DougC

    DougC Guest

    I do not understand what you are saying here.... The Mag-LEDs and Ever-LEDs are drop-in replacements, they fit right in to any regular miniature-flanged flashlight bulb socket. And the front end of the LEDs is smaller than the globe of the light bulb.

    Maybe you were looking at the triple-led bulb for the mini mag-lite? (which is different)
  10. sparky

    sparky Active Member

    Cree LEDs are apparently the best. Seoul P7 was another commonly mentioned LED.

    As for the part about not hooking an LED right up to batteries, I think that's incorrect. The Coast P7 flashlight I had was supposedly "unregulated", which meant that as the batteries slowly die, the output constantly decreases over tens of hours, and as the light output decreases... the cooler the bulb. On my regulated Fenix L2D Q5, the bulb stays hot if left on for a few minutes... and supposedly it will overheat if you leave it on for 10 minutes or more, if it's not air cooled by being mounted to the front of a MB. But I'm guessing if you're hooking this up directly to the white wire, it prolly should be regulated.
  11. sparky

    sparky Active Member

    The Cree Q5 in my L2D Q5 looks like this beamshot from that website linked above...


    It's excellent for the money. The transformers keep blowing around here (prolly keep getting wet from all the storms), and my friend's uncle brought out his huge maglite, and my tiny LED flashlight was less than half the price, 3 times wider & more powerful, only runs off of 2-AAs as opposed to 3 or 4 Cs or Ds, and I'm pretty sure these smaller batteries last longer too, due to the efficiency of the Cree bulbs. Good stuff.
  12. Torques

    Torques Guest

    Here are a couple of response I received from one of the led manufacturers. Evidently I can't use a led with the approximate 6 volt ac current. If anyone knows differently, please let me know. Also if anyone knows a better, brighter bulb they are using other than the KPR112, please let me know. I am interested in the manufacturer, not a member supplier here, thanks in advance.

    The power supply needs to be 6v max, with the center bulb contact positive (+) to work correctly. If it goes over 6v you'll fry the LED.


    doc.......@hotmail.com[/email] wrote:

    I have a motorized bicycle that is now powering a kpr112 bulb (approximately 6 volts ac) Will the lpr 113 bulb work with that power type (6 volts ac)? Thanks.

    Also- only runs on DC power.

    doc.....@hotmail.com wrote:

    I have a motorized bicycle that is now powering a kpr112 bulb (approximately 6 volts ac) Will the lpr 113 bulb work with that power type (6 volts ac)? Thanks.
  13. Torques

    Torques Guest

    I had the same size bulb as the kpr112 which fits my socket and the maglite upgrades were dimensionally the same (2, 3, and 4 cell) AND the bases were bigger than the kpr113 socket size which is the p13.5s I believe. Evidently led's don't work on ac so I'm out of luck.
    Last edited by a moderator: Sep 16, 2008
  14. loquin

    loquin Active Member

    You would need to rectify the AC on the white wire to convert it to DC (using 4 schotsky diodes, which have a very low forward voltage drop, in a bridge rectifier arrangement.) You'll also filter it with a small capacitor, and regulate it, to drop the output voltage down to no more than 6 volts. However, the difficulty that you would experience is that an uncharged capacitor would act as a 'short' until it charges up.

    If you fire up the engine, get it above an idle, and then switch in the AC-DC circuit, you should be able to charge a capacitor without killing the engine. Once it's charged, it no longer acts like a short. Or, you could add series resistor to limit current flow, and a micro-relay, to bypass this resistor when the capacitor voltage is high enough to limit the current flow by itself.

    The regulator circuit should also be a switching regulator, which has very high efficiencies when reducing voltage levels. Linear regulators work by wasting the difference between the input voltage and output voltage as heat. The power loss is the difference in voltage, multiplied by the current flow.

    If you can find a used mag-light, where the batteries have leaked, you could probably get it for next to nothing. Then, cut it down so that the barrel is about 3 inches long & seal up the barrel. (You could put the ac/dc converter & regulator circuit inside the barrel...) Add the LED bulb, which is requires between 2 and 3 watts, to the head, & you should be good to go.
    Last edited: Sep 16, 2008
  15. Torques

    Torques Guest

    Wow thanks for the information. The electronic suggestions, etc overwhelm me. Is there anything already built for this? How would I know what to buy or how to hook it up?
  16. duivendyk

    duivendyk Guest

    I think Loquin is pretty much on the money,you need to rectify the white wire output,a switching regulator would be best(less current drain),allthough that is not absolutely necessary.what LED 's do you want to run (current drain)?.Read my thread LED's the low down,for useful background info.Another possibility would be to charge a 6V SLA battery (Sealed Lead Acid),they are not all that expensive and run the lights from it.Then you have some storage too and a constant supply voltage which is what you really need.That looks like a pretty good scheme to me.
  17. Torques

    Torques Guest

    Can't find that thread you mentioned. I just want to run a led that is the same socket size as a kpr112 (p13.5s base). I do not want a battery, I just want somehow to convert the ac to dc to run the led but I need instructions. Doesn't just a diode change the AC TO DC?
  18. Torques

    Torques Guest

    I just found the thread and will read it now.
  19. Email

    Email Member

  20. motor head

    motor head New Member

    tighten the idle screw on the engine will be near the throttle assembly then it won't die