Ready for a man's light-
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  1. #1

    Join Date
    Feb 2005

    Ready for a man's light

    Hi. I've been reading through threads here after being routed over by a link on cpf. Was much entertained by a couple of Troutie's epic build threads. Quality entertainment.

    I'm tired of the taking my life in my hands everytime i mount up after dark--i need a real light. My main need is for a medium-powered, but efficient, barlight for my tourer. I plan on using a 4xNiMH AA battery pack (with a small 6V solar panel to trickle charge during the day), and think about 100-200 lumens would be fine under most circumstances, with perhaps an option to step it up now and then.

    So, i'm thinking of an MCE with a low current for best efficiency and flexibility for brighter burn if/when needed. I've seen that optics can be problem. I have a lot of ideas, but expect that most of them would lead to some unfortunate fireball or trip to the rubbish bin for expensive parts. So, some advice and help would be much appreciated.

    Is a single, underdriven MCE with 4xAA a good option for a sole light? What optic and driver would be best?

    Thanks in advance.

  2. #2
    mtbr member
    Reputation: troutie-mtb's Avatar
    Join Date
    Sep 2007
    Thanks Flandry I had much fun doing the threads too .
    You do get good effiency from multiple leds at low current and if you are out touring in the sun then the solar charger sounds a great idea.

    Have you explored dyno lights for your needs . there are some good threads on here from the long distance dyno lights guys .
    they may be a better more reliable system for your never have to worry about batteries and chargeing.

  3. #3
    mtbr member
    Join Date
    Feb 2009
    A single MC-E has the plus of size, but they are more expensive and a little less efficient. The best MC-E is about 7% less efficient than the best single LED emitters (XR-E and XP-E) The XP-E data sheet implies that a R3 bin may be available ant that would be 14% more efficient.

    For maximum reliability two lights may actually be the way to go. That way if one quits it will not get suddenly dark. That sucks big time. You could also put one on the bike and one on the helmet. You could even go with 2xAA on each light for a smaller size. Using AA's can also give you the option of using non rechargeables in a pinch. There are some boost drivers for flashlights that have several modes. One that has a high, medium, and low modes would be great for you. Some have up to 20 crazy modes.

  4. #4

    Join Date
    Feb 2005
    Thanks for the replies. I looked into dynamos and in theory the solar panel on the back rack feeding either 4xAA or 2s4pxAA is the better option for long distance touring. I will also plug in my smartphone that will be my GPS and such. Having 4.8V as the battery nominal voltage means (will have to test this...) that i can use it directly for USB-powered devices (ie smartphone) and use as the driver for the LEDs.

    I had thought that a single, small light would be the most convenient. MC-E seemed best in that context. After poking around on the DE site yesterday and seeing that an M or K bin MC-E is the best available, i realized the value of using some R2 binned XR-Es instead. Three of those come out cheaper than one MC-E, anyway.

    So, multiple XR-Es or XP-Es. I'm not really familiar with XP-Es, and DE doesn't have them AFAIK. Unless there's some compelling reason to order from somewhere else (i'm prepared to wait for the DE order), the price and free shipping make sourcing from DE appealing.

    Here's what i've got in my basket: 23mm optics for CREE LEDs. I don't know anything about these except they have "snap on" ease of use and people say they are a good pattern for bike lights. cheap 3.6-9V regulated 800mA drivers. Read that these can be adjusted to lower amperage by shaving or replacing the resistor, which is great, and they are ~ 85% efficient in my usage context.
    3x XR-E R2 WG emitter on premium star. Only R2-binned emitter on DE.

    My rough plan at the moment is to test to see if i need all three XR-Es or if two will serve. Then, i will probably wire them up to two of the 800 mA drivers in parallel and adjust one driver to put out around 300 mA. That will give me a low (300 mA), medium (800 mA), high (1100 mA) using two switches, and some redundancy in case one emitter or driver blows. I could throw in a third for a panic mode of 1900mA, but i suspect 1.1A is going to be enough (haha sorry if that's an evil word here ). I have an EOS i'm going to mod with a Seoul P4 to use as a helmet/camp light.

    What i don't know is whether i would be better off with a reflector or polycarbonate optic for my light. Because i'm going with XR-Es, i could combine a floody and spot optic if needed, but i'm overwhelmed by all the different options. I'm also ordering one each of the two different bike mounts to try on the handlebars. There is also room on the tie bar of the front rack (the bit that goes around the tire to join the two sides) to mount a light if i could figure out how to get stability there. Anyone done that before? Possibly the wrong forum to be talking about front racks.

    How'm i doing? Suggestions?

  5. #5
    mtbr member
    Join Date
    Nov 2008
    if this is for road use then you might want to consider one of the multimode drivers.
    eg. this one. It gives high,low, slow flash, fast flash and strobe. Although it is says it will only go up to 8.4V I have had mine up to 12V without any apparent signs of problems and the spec of the driver (PT4105) is up to 18V. However, at the moment I only use it with 4 NiMh and one Q5.
    The 1920 optics have quite a tight spot- more of a helmet light optic but might also be good for road use, particularly if you have 2 or 3.
    You could combine it with 4626 or 4600 to get something wider- I'd recommend getting a selection and see what suits you.

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