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Electronics LED bike lights?

Discussion in 'Modding' started by bigsharn, 17 Oct 2010.

  1. bigsharn

    bigsharn Officially demotivated

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    Just wondering how feasible this is, I've seen a few LED bike lights going for stupid amounts of money, figured it's probably cheaper to make my own set...

    Why make my own set? Mainly because I'm tempted to get a KMX trike and the light mounting kit is £10... I reckon I could fit some lights to the top of my seat for cheaper than that (granted I'd need a waterproof casing, but still)

    Any idea what kind of power requirement I'd need and how much battery life I'd get from a set of 4 rechargables?


    Thanks in advance
    Sean
     
  2. riekmaharg2

    riekmaharg2 has finished Blue Horizon

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    I would doubt you could make a waterproof LED torch for less than £10, not a decend bright one anyway. However if you still want to try:

    It would depend what LED you use, there is a huge range with all sorts of different power requirements. Look on the rechargables for their mAh rating, for example if your batteries have 2500mAh then they can output 2500 milli amps for an hour, or half that for two hours e.t.c

    It also depends on how you connect the batteries together, if you wire them in parallel then you add all the mAh ratings together to get the total and the voltage will be the same as a single battery, however if you wire them in series then you add all the voltages together and the current will stay at the value of just one battery.
     
  3. capnPedro

    capnPedro Hacker. Maker. Engineer.

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    Check out dealextreme.com
     
  4. barry99705

    barry99705 sudo rm -Rf /

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    Heh, got lost on the internet for a couple hours after googling "home made bike light". There's a lot of awesome out there. There's also a lot of redneck, that's going to catch on fire.....
     
  5. Andy Mc

    Andy Mc Well-Known Member

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    There is a fair bit of this around the net if you look. Most use Cree XE/Luxeon Star 1 Watt LEDs. Heat is an issue if you use more than 1.

    Check out this instructables search for a few build guides. With a little google-fu you will find plenty more.
     
  6. bigsharn

    bigsharn Officially demotivated

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    Ah, nice one... I never knew about the series/parallel batteries thing so that's definitely on the cards. In honesty I need a light (or two; front and rear) to be seen (I reckon 1 LED with a reflector should work, the 1W should cut it, right?), and a light to see with (probably use 4 or more LEDs for that).

    The other thing I've noticed, red LEDs are significantly less powerful than white, and I can't find a rating for them in lm, would one/light be enough or might I need a few?

    Oh: and thanks Pedro, but I'm in the UK :(

    Thanks again
     
  7. barry99705

    barry99705 sudo rm -Rf /

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    Honestly I'd go for a halogen light. I used to live in Fairbanks AK, which has a fairly large population of bike riders, year round. Those led lights were only visible from behind maybe 50 to 100 feet away. If you do go led, a 1watt in the back with a red diffuser would probably be the way to go. You're on a trike, so a little extra weight shouldn't be too big a deal. I'd use the battery you can find in a kid's Power Wheels. They usually sell them at toy stores, even have the chargers there. The 12v ones are usually around 9Ah batteries, so they'd run a couple of the bigger led's for quite a while.
     
  8. riekmaharg2

    riekmaharg2 has finished Blue Horizon

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    I would go for at least 3W leds for the front light. I made a torch with two 3W led's one with a lens on and one without a lens, so then both the distance and close up is illuminated. My torch is powered by 6 AA 2.5Ah batteries, two sets of 3 in series and then the two sets are connected in parrallel to give a total of 3.6v at 5Ah, and it lasts around 3 hours before it starts to die.
     
  9. Andy Mc

    Andy Mc Well-Known Member

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    One thing to take into account for road use is to make sure you do not dazzle any other road users.
    You don't want the man pulling you over.
     

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