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Homemade *bright* LED light setup

Discussion in 'Technical & FAQ' started by Haku, Aug 15, 2007.

  1.  
    Jeremy

    Jeremy Just Joined

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    I wish I'd thought of this!

    At only £3.99 each I'm tempted to buy 4 of them and wire them all in series for an array-type front light that will work from my 48V battery. The fact that they are 12V units makes it easy to use as many in series as you need to match your battery voltage.

    The only snag I would have is getting enough space to mount four lights, as they'd have to fit on the short bar above my "bottom" bracket (which is actually right out the front).

    Thanks for the link, I may well get some to play with.

    Jeremy
     
  2.  
    Haku

    Haku Finding my (electric) wheels

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    Grandad, I know I should have used resistors for the front LEDs - that's why 3 of them started flickering and died - but I've gotten away with not having to use resistors since I dropped the output voltage of the regulator to 3v exactly, since then I've not had any more do the 'death blink'.
    However I do miss the extra brightness that 3.15v gave so I'm thinking of re-doing the front light with 30x 3mm LEDs as I should be able to squeeze that many (perhaps more) into the reflector and the beam spread is more pleasant, in that it has a more even decay from the center rather than the round spotlight of the 5mm LEDs.

    Now it's getting darker quicker and the weather is turning for the worse I'll finish off my current setup, and do the photo & diagram thing so others can see what I've done. After that I'll look at re-doing the front light as the back one is certainly bright enough with 4x LEDs mounted behind the reflector, most vehicles give me plenty of room when overtaking :)
     
  3.  
    john

    john Finding my (electric) wheels

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    update on my headlights

    I bought a couple more MR16 LEDs from here eBay UK Shop - IT Global Solutions: Lighting, Bathroom, Kitchen
    These have 24 LEDs each and are rated at 1.5W. I found that at 15V they take 100mA so I used a LM317T to drive the two in series. This gives me 3W of light and they are also more directional than the others so they light up the lane nicely and also throw out enough to the side to light up the kerb/hedge etc.

    I also notice that some rain got into the last bulbs. I think this is because the front glass is not sealed to the body, so I ran some super glue around these to seal them.

    I had to make a new bracket for the two bulbs, like the last but with one on top of the other and a little higher so that I don't get as much shadow from the wheel.
     
  4.  
    Grandad

    Grandad Finding my (electric) wheels

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    I did it my way.

    Haku, John et al.

    I have borrowed a few of your ideas and am now modifying the lights on my bike.

    [​IMG]

    What do you think of it so far?:rolleyes:

    (I left myself wide open for rude comments there!):D

    You can see how it is progressing here.
     
  5.  
    Grandad

    Grandad Finding my (electric) wheels

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    Wasted effort?

    I am just wondering if I am wasting my time. It might have been easier and cheaper to modify an existing led lamp.
    [​IMG]

    I have just found this lamp at £4.26 plus postage and others here.
    They run on internal batteries but could probably be modified.

    I don't know what the quality is like however. Anyone else used them?
     
  6.  
    Grandad

    Grandad Finding my (electric) wheels

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    Finis.

    I have now fitted a socket to the lamp and mounted the modified light onto the bike.

    As the lamp is rated at 12 Volt, 1.3 to 1.5 Watt I connected it to the 24V battery through 3 off 374 ohms in parallel to give a current of 104 mA and 15V across the battery so using 1.56 Watts. A little over the top but no problem on an overnight soak test.

    [​IMG]

    Photo top left:
    Lamp now connected through the rear using the original connectors.

    Photo top right:
    Early dusk. Shows both the LED Cateye Opticube lamp on the bars tilted down for normal use and the modified lamp below used as an 'always on' running light.

    Photo bottom left:
    The beam pattern shown onto the garage door with the Cateye tilted up. The Cateye gives a sharp pattern where as the pattern from the modified lamp has a more diffused edge.

    Photo bottom right:
    Shows the two lamps shown from the front with with the Cateye tilted up for comparison. I must admit that the light from the modified lamp is better than expected so I am well pleased with the project.
     
  7.  
    giguana

    giguana Just Joined

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    I have some spare voltage converters if anyone wants, with 36/48 volts input and 5v/80w output. they can be connected in series to make 10/15V output, which is very good for LEDs because most power LEDs are rated at about 3.3V so three in series makes 10v... about 5 cm by 5 cm by 1 cm, 50 g

    also it means you can attach regular bike lights to them because 5v is the same as 4x aa/aaa batteries.

    I am thinking of using one 12v/10w halogen headlamp and 2 really cheap flashing back lights from eBay wired in series to make 5v...

    I have tried the converters at 24V and the output is 5.03v, but I don't have the data sheet, they are rated at 48v in, similar ones can do in between 18 and 70 V but I'm just saying in between 36 and 48 because I don't know. £3 each:) including postage, as many as you want
     
    #27 giguana, Jan 10, 2008
    Last edited: Jan 10, 2008
  8.  
    Grandad

    Grandad Finding my (electric) wheels

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  9.  
    Haku

    Haku Finding my (electric) wheels

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    Grandad, blinded any drivers yet? hope so :D

    For a long while now I've been trying to work out how to add more lights to my bike, ones that aren't for my extra visability along dark roads/paths but ones for other road users to see, but they have to be stealthily added so like my reflector lights it doesn't appear like they're there when not powered up.

    And today I came up with the perfect solution: LEDs in the plastic caps covering the bolts holding the wheel axles. White for the front and red for the rear, with the tops filed down to give a really wide angle, then I'll have full 360 degree visability with my lights :)
     
  10.  
    Haku

    Haku Finding my (electric) wheels

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    Had to have a little play, managed to dig up a white and red LED, file off the heads so they're as short as can be which changes their viewing angle from around 15 or 25 degrees right up to almost 180 degrees, stuck some wire & resistors on them and then blu-tacked them to the ends of one side of the wheel axles:

    PegLeds! (I wonder if I can trademark that?)

    [​IMG]
    [​IMG]

    Looks much better than the camera can show, the front LED is a 3mm one and appears to be bright enough to give out additional side-viewing light for when going slow along unlit paths.

    I'm just about to order a new front reflector & a big bag of LEDs because I'm going to double the brightness of my front light by mounting as many 3mm LEDs as possible in the new reflector - take that, you cars!


    edit: I've just temporarily wired up two 3mm white LEDs with the ends cut off to remove their spotlight effect, one each side of the front wheel axle end and went out for a spin, they work better than expected as the road immediately round the front wheel is lit up very nicely, which also gives me another idea for my final lighting setup I'll be creating soon (the front reflector will have 45 3mm LEDs embedded in it :D )
     
    #30 Haku, Apr 22, 2008
    Last edited: Apr 23, 2008
  11.  
    Haku

    Haku Finding my (electric) wheels

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    3mm LEDs arrived today, 10x red, 50x white. We're gonna need a bigger bag of white LEDs...

    After doing some drilling today on the original reflector to actually determine how many 3mm LEDs I could comfortably embed into it I discovered I can get 60. Yes, 60, 6 rows of 10 holes drilled in the reflector won't adversely affect the structural strength of it and it will still partially work as a reflector:

    [​IMG]

    You can see the test row of 5 holes on the right, then test row of 6 on the left and a partial grid in the center. It's going to be well over 3x the brightness of my present 17x 5mm LED setup which enables me to see along unlit paths/roads quite easily, I love cycling at night so things are going to be even more fun!
     
    #31 Haku, Apr 24, 2008
    Last edited: Apr 24, 2008
  12.  
    Grandad

    Grandad Finding my (electric) wheels

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    Rhyming nonsense.

    Haku, Haku burning bright.

    In the middle of the night.

    Just watch out for Mr Plod.

    Blinded by the sight of mod.

    If he catches you just once,

    He might bop you on your bonce.
     
  13.  
    Merv

    Merv Just Joined

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    Hi Haku, Like your idea using Led's. I should include a fuse in one of the lines though as they can go short circuit, specially when driven hard! Another point worth knowing... The "Pound Shop" sell LED camping lights_ 24 very very bright led's in a circular plastic housing. All you need do is to carefully remove them from the PCB. That's what I call real value for money.
     
  14.  
    Haku

    Haku Finding my (electric) wheels

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    The reflectors I bought from sjscycles.co.uk arrived today, 2x Cateye front reflectors (only ordered one bracketed but both arrived bracketed) so I had a spare in case I screwed one up, and a Cateye back reflector which I only threw into the order because it was cheap and might have been good on my bike except for the mounting block on the back sticks out quite far and the setup I have for the back light/reflector (shown in the first post of this thread) is much thinner.

    I managed to steal 15 mins on a milling/drilling machine today so:
    [​IMG]

    :D


    Merv, the LEDs won't be directly powered from the bike battery's voltage but through a 5v regulator, then the LEDs will be powered in parallel sets of 3 with a current limiting resistor. The regulator will have a fuse between it and the bike battery so it'll blow if anything shorts, a rough estimate showed I'll need probably 1.5A at 5v to power all the LEDs.
     
  15.  
    Haku

    Haku Finding my (electric) wheels

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    Received the 33ohm resistors just before the weekend so I stuck 60 LEDs on a breadboard with 1 resistor per 3 in parallel and gave it 5v (all 60 LEDs with resistors took about 1.1A at 5v), the amount of light coming off them was brighter than an energy saving bulb that's rated at 60 watts light output! testing it outside in the dark it was somewhat unreal how clearly you could see everything. I ran them for about 36 hours straight and none of them flickered, dimmed or died, a few looked marginally dimmer than the rest but you can't expect cheap LEDs to manufacturered to a high standard.
    Whilst the burn-in test was commencing I glued in the 60 LEDs, don't like working with superglue but it was the best type to stick them in with:

    [​IMG]

    What doesn't show up in the images is how the reflector has gone a little 'milky white' because of the superglue, meaning it works even less as a reflector than before I glued the LEDs in but it's function now is to be a bike light in disguise so that's ok. I'm halfway through bending/cutting/soldering the 120 individual LED legs and should have them finished by tomorrow.
    As well as gluing in the front light I set-to and did two duplicates of the back light you can see in the first post.
     
  16.  
    john

    john Finding my (electric) wheels

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    Isn't it better to put strings of LED's in series and use a resistor for each string rather that putting the LED's in parallel? That way you can ensure that each LED gets the same current.
     
  17.  
    Jeremy

    Jeremy Just Joined

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    Yes, it's a lot better to use series strings. The plus points are that there's no need for a voltage regulator at all, the overall system efficiency will be higher and the LED brightness will be well-matched, with very little variation from one LED to the next.

    Each white LED will drop around 3.5 volts or so, which means that around 8 LEDs can be used (with a single series resistor) on 36 volts (allowing for the lowest likely battery voltage), or 12 for a 48V system. The individual series strings, with series resistors, can be connected together in parallel.

    For 60 LEDs on 36V, then maybe ten strings of six LEDs, with just ten series resistors, might be best. The current drawn would be around 300mA, for 30mA per LED.

    Jeremy
     
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    robertozm

    robertozm Just Joined

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    Hello Haku:
    I am new in this forum as in electronics, so if I ask something really stupid do not be to surprise, since I have not a clue about electronics, BUT I am on an Ebike "experiment".
    I have bought from goldenmotor the kit and also a battery of 36volt 15amp, and I would like to feed my lights from this battery.
    I have been looking to the switching voltage regulator and the limit is 30volt, is any way I could solve this? May I used some of them in parallel or series?
    If I buy from ULTIMASTORE - Energy Saving Lamps, LED'S, LED and put a few of them in parallel will it work?

    As you can read I am completely lost, and any comments will help me a lot.
    Thanks
     
  19.  
    john

    john Finding my (electric) wheels

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    As these are rated at 12V, you can simply put 3 of them in series and connect them directly to your 36V battery.

    They will however dim a little as the battery runs down so you could do what I have done and put 2 in series with a regulator (LM317T - these only cost pennies).

    BTW I now use MR16s from here eBay UK Shop - IT Global Solutions: Lighting, Radiator as I find them more directional and so give a better beem although they are more sensitive to voltage drop.
     
  20.  
    robertozm

    robertozm Just Joined

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    John THANKSSSSSSSSSSS:D
     

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