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  1. #1
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    25K+ Lumens helmet mounted light (100W led bike light)

    My first post here - I joined up to share my latest project.

    Essentially, It is a 100W / 7000Lm street light chip sitting behind a projector lens.

    The head unit only weighs 300grams - this compares favourably with the 250grams the 2x Magicshine P7 lamps I used to run on my my helmet.

    The heatsink is a pure copper northbridge unit with a 50mm 16CFM fan mounted behind.

    Batteries are 12x 2.9AH Panasonic 18650s in series - ie 44V nominal.

    I normally run this light @ 120W, using a continuously variable pulsewidth control. I have an instant 'boost' button that pulls the MOSFETS high and provides upto 400W for 20second bursts.

    Battery lasts approx 45mins+ @ 120W continuous and 20second 'boost' every 5 mins, before the low volts data loggers trigger a 3V cell alarm (all 12 cells are independently logged and alarmed).

    Last night:
    I just took the monster bike light out in the park.
    Attached are the 2x data logs (1 log per 6 cells – 12x 3AH li-ion cells in total).
    The blue trace on top is the total 6cell pack voltage.

    There are a couple of weak cells to keep an eye on – I have a few spare cells to swap out if needed.

    Other stats for that short bike ride:
    Peak power = 403W
    Peak current = 9.56A
    Total WHr = 39.8
    Total AH = 0.91
    V min = 39.8
    V fin (no load) = 45.6V

    Recharge back to 4.2V per cell = 1.05AH

    Note, I used 150W – 200W in the main, except for a few sections where I turned it down to 30W due to high reflected light of close objects -ie where the track weaves between bushes.
    Ave pwr approx 160W continuous – averaged over the 15mins. Batts approx 1/3rd discharged.

    The short bursts of low volts = the high load from burst of direct drive – ie MOSFETS fully on instead of the normal pulse width control. The direct drive is typically 350W (can be 400W on fresh charge) but generates a LOT of heat (LEDS are only approx 10% efficient) and can only run it for 20 secs at a time.

    I also reduced drive to 100W during the slow uphill 1st gear slog back home . Yes, I can really feel the heat through the bike helmet when going slow , at the higher power levels.

    BTW, I am using 2x JUNSI CELL LOG 8S units – tiny – smaller than a match box and back lit – amazing units.
    And I am also using a GT POWER RC 130A power meter – measures power directly, records peaks, min V etc – also back lit for night – saves carrying 2x multimeters !

    Bottom line:
    • For 1/3rd of the ride, 5-30W is more than enough
    • for most of the rest of the ride - 100-200W is the go
    • for the fast down hill - use full power - 250W-400W - too much light is never enough for these sections.
    Ihave a plan for feedback based automatic light control (eg use a cheap B&W security pinhole camera or simple focussed LDR).

    BTW2 - My commercial 10W Magicshine led bike lights look distinctly feeble now.

    The lesser beam shot is a Magicshine P7. The distant hedge is 65m away from the light.
    Yes, this light is not a thrower - but is I do not ride fast enough for this to be an issue.
    Last edited by Pepster; 08-23-2010 at 05:39 PM. Reason: my mates could not find this !

  2. #2
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    Pics!

  3. #3
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    Yes, pictures please!

  4. #4
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    Quote Originally Posted by King Kasper
    Pics!
    I am new here, and couldn't get the pics to work.

    2nd try:

    The dim pic is a 1x 10W Magicshine P7 for control.
    Attached Thumbnails Attached Thumbnails 25K+ Lumens helmet mounted light-p1100306.jpg  

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    25K+ Lumens helmet mounted light-p1100335.jpg  

    25K+ Lumens helmet mounted light-p1100343.jpg  


  5. #5
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    Quote Originally Posted by fujio001
    Yes, pictures please!
    More pics:

    BTW, this light is heaps of fun to ride with - big grins all round. I have the battery box zip-tied to the top of the bars sitting on top of a thick foam pad. The control pod (will be much smaller soon) sits on the bars with the red boost button next to my left thumb.

    The fan runs quiet (approx 10V ave) @ 120W, but roars it's tits of (Ozzie expression) @ 350W+. This chip will run @ 300W all night with the slightly bigger (but 200grams heavier) heat sink I have.

    Another design I considered was to use a CPU water cooler block (eg the complete Corsair kit) that would be light on the helmet and allow 300W+ continuous power (would also need 2x 5AH 6cell RC lipo packs).
    Attached Thumbnails Attached Thumbnails 25K+ Lumens helmet mounted light-p1100325.jpg  

    25K+ Lumens helmet mounted light-p1100326.jpg  

    25K+ Lumens helmet mounted light-p1100327.jpg  

    25K+ Lumens helmet mounted light-p1100328.jpg  


  6. #6
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    Wicked.................

  7. #7
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    More pics:

    I do not notice the <1kg battery on the bars and the 300gram light head on my helmet is fine for me. The lens is glass.

  8. #8
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    More pics:
    Attached Thumbnails Attached Thumbnails 25K+ Lumens helmet mounted light-p1100346.jpg  

    25K+ Lumens helmet mounted light-p1100347.jpg  

    25K+ Lumens helmet mounted light-p1100349.jpg  

    25K+ Lumens helmet mounted light-p1100350.jpg  

    25K+ Lumens helmet mounted light-p1100351.jpg  


  9. #9
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    Quote Originally Posted by fujio001
    Yes, pictures please!
    Data log traces for pack A and pack B (6x li-ion cells each). The blue trace is the total pack voltage. Note the V dips when 'boost' is applied. You can see the effect of the varied load on the batteries when I adjusted the power up and down to suit track conditions.

    BTW - the creek crossing (some times treacherous - I have gone over the bars here...) is a total breeze now - I can now clearly see to the bottom of the creek - I couldn't do this with the 2x Magicshine P7s.
    Attached Thumbnails Attached Thumbnails 25K+ Lumens helmet mounted light-18-8-2010-ride-park-charge-pack-1-sec-sample-li-po-charger-1-crop.png  


  10. #10
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    That is one badboy led, hats (helmets) off to you for pulling off such an amazing light!!!!!!!

    I wish that I lived somewhere that wasnt pi$$ing with rain!

  11. #11
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    Quote Originally Posted by bumphumper
    That is one badboy led, hats (helmets) off to you for pulling off such an amazing light!!!!!!!

    I wish that I lived somewhere that wasnt pi$$ing with rain!

    haha, was just about to say, I hope it doesn't rain.

    Impressive output though !!

  12. #12
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    Thanks.

    I have ridden in light rain and the fan survived. The led just burns any moisture off as it typically runs at 65deg C, and 95degC after 20secs of direct drive.

    I plan to place the battery and loggers in a lunch box with clear top.

    The light reflects of the falling rain something fierce though.

  13. #13
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    Sure takes care of the tunnel effect!

  14. #14
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    trailguy1: WT# is that?
    trailguy2: Looks like a plane, but it is flying pretty low?
    trailguy1: Or a guy with a streetlamp on his head... or a UFO
    trailguy2: Are you nuts, nobody is that crazy. Did you bring the camera?

    I think I'd pack a fire extinguisher if I was using that light - good job! Thanks for posting pics too.

  15. #15
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    That LED is massive! Where did you get it?

  16. #16
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    Quote Originally Posted by fujio001
    That LED is massive! Where did you get it?
    Just type "100 LED" in to eBay, eg;

    http://shop.ebay.com/i.html?LH_BIN=1...&_sop=12&_sc=1

    I was going to use the 300W chip but it is 4x more expensive. The 100W chip seems happy enough @ 200W continuous and 400W for short bursts - and is the same physical size (same chip?) as the 300W version.

    The chip is a 10x10 array - ie 100x 1W leds. Due the the large chip size, I do not think it is possible to focus this light any tighter with a small diameter lens.

    But, I LOVE the beam spread. Previously, I could hear the creek running parallel to the trail but not see it unless I turned my head (and then I could not see the trail...), now, the whole park is lit up. I have another, larger 65mm lens that has an even wider beam that I prefer, but I have to resolve some packaging issues.

    Current lens (I think - I have tried several) http://cgi.ebay.com/100w-LED-optical...ucational_Toys

    Current heatsink, type in eBay: "Copper NorthBridge Cooler Cooling Fan Heatsink"
    http://cgi.ebay.com/Copper-NorthBrid...efaultDomain_0

    You will need a led base & lens combo, I used the base from this, (eBay) "60mm Lens Reflector with Base for 20-100W LED Lamp Blub" http://cgi.ebay.com/60mm-Lens-Reflec...efaultDomain_0

    The LED is 10x10 - ie 10 LEDS in series = 10 x 3V = 30V approx needed to drive 100W.
    I chose to use a high volt source (12x li-ion cells = 44V nom.) pulse width controlled. This drive arrangement is approx 99% efficient @ 300W due to the tiny on resistance of the series MOSFETS. The fan uses approx 1%.

    I could have used lower volts and some kind of buck-boost cct, but have you seen just how big a 300W ferrite core is !! and there would be plenty of heat issues due to the 80-85% efficiency of the driver. So, I recommend using 12x top quality li-ions (I used panny 18650s - but they get up to 50deg C. I would recommend using 2x RC 6cell li-po packs for warmer climates - and would get much more power on direct drive 'boost'.

    Li-Fe have too lower cell voltage - would need more cells, and their power density is much lower. The Panasonic 2.9AH 18650 Li-ions have the best power density currently available. When these wear out, I will replace them with the new 18650 cells Panny promises will have 40% greater power density - out next year.

    If waterproofing is a priority, consider using a water cooling head instead of a heatsink and fan, and then seal the whole light head up.

    BTW1 - I use a non-contact infrared temp gauge for testing
    BTW2 - @ 100W, the led is 10% efficient, thus 90W of heat is generated, haf of this radiates out the front, and half (eg only 45W) is dissipated by the heatsink and fan. A modern CPU fan is waaay too big (and heavy) - I tried this.
    BTW3 - the led in the beam shot is a 3500Kelvin (a bit yellow but ok on 'boost') and the led next to the ruler is 6500kelvin (OK @ 100W, a bit blue @ higher powers). I recommend the 5000kelvin led for all round use. The 3500 kelvin led has much more yellow phosphor than the 6500K one. When over driven, the blue elements (white leds are blue +phosphor) dominate the yellow phosphor and the colour shifts up a bit.

  17. #17
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    where abouts do you live pepster? niice bush!

  18. #18
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    Quote Originally Posted by King Kasper
    where abouts do you live pepster? niice bush!
    Adelaide, South Australia.

    The beam shots are in my back yard. We love this area - only one block from the National park (where I ride @ night).

    I watched a big Koala slowly walk down my drive yesterday. The Koalas have a very loud bellowing grunting sound - a mating call, I believe, that was quite disturbing when we first moved here. Lots of late night bangs and crashes as the Koalas and Possums (can see possums every second night) climb the gate, and drop down on the tool shed roof.

    I will try and post a pic of a Koala using this new light.
    Last edited by Pepster; 08-22-2010 at 05:05 PM.

  19. #19
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    dude awesome! i live in Wollongong, NSW. good to see some aussies on the forums

  20. #20
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  21. #21
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    Quote Originally Posted by Pepster
    I will try and post a pic of a Koala using this new light.
    That I'd like to see! Can you get it to ride the bike, while using the light?

    Make a fellow Aussie swar off drink seeing a Koala lit up like a shopping center lot riding down the trail!

    I could use one of these on my lawn tractor for night mowing.

  22. #22
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    Quote Originally Posted by BrianMc
    I could use one of these on my lawn tractor for night mowing.
    No good, Brian ..... the little fella won't be able to sit on the seat and steer at the same time

  23. #23
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    I have also seen reference to a prototype 1000W Led on the web.

  24. #24
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    1000 W LED what a bright idea? I wonder if a Koala could use it? (Sorry, just finished my beer.)

    I would love to see a Koala photgraphed in the light from your bike light.

  25. #25
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    I was going to guess you’re Australian. Why? Well, in the world of overkill, Australians seem to be more passionate about taking things one step further—I’ve seen this with high-horsepower car hobbyists many times before. Cheers to you for an overkill job done right!
    QUOTE from MTBR.COM: You have given Brewtality too much Reputation in the last 24 hours, try again later.

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