First LED attempt - retrofit- Mtbr.com
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  1. #1

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    First LED attempt - retrofit

    HI gang,

    Have been a lurker here for some time and am about to make my first attempt with using LEDS. I should firstly say this forums is brilliant. I've learnt heaps, but am now hitting a few walls as I commence this first project.

    My plan is to retrofit an old NiteFLUX VisionStick 5 halogen lamp.

    I have purchased the Cutter LCMR11XR-E Kit: http://www.cutter.com.au/proddetail.php?prod=cut790

    I do have the machine the inside of the NiteFLUX housing to make it all fit, but I wanted this kit as it seemed an easy/cheap option to have my first stab at. I plan to go the 80/700mA dual level option.

    I've read and read and searched and researched. However, being new to electronics and LEDs I have some maybe dumb and not so dumb questions

    1. How the heck do I wire the driver? I can see the terminals (?) where the LED +/- go so that's fine. Do I need to use the GROUND? What do I do with the HIGH/LOW (i.e. where does the +/- go from the battery)?
    2. I get the buck/boost idea, but am not sure what this driver actually is? What battery voltage/range do I need?
    3. I plan to put together the battery myself using AAs. I kind of get the idea of cells in parallel = adding the voltages and in series = more power (Amps? Amp hours??). How many and what type will I need?
    4. With the 80/700mA option, what kind of switch will I need? I had the thought I'd like a toggle type switch with 3 positions = Off/On80mA/On700mA. Basically something easy to hit/change that I can retrofit into the existing switch position on the NiteFLUX housing (top).


    I apologise if these Q's are covered in the forum elsewhere, but I have searched.

    Any help is very much appreciated and I promise I'll get up to pace ASAP ;-)

    Will post pics as I go.

    Cheers,

    Aaron

  2. #2
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    I've not wired this driver before, from the pics it looks pretty straightforward.

    1. Battery + gets switched from +LOW to + HIGH to get the dual range. Battery - connects to GND.

    2. It is a buck type driver. Your minimum battery voltage needs to be about 1.2V higher than the Vf of you LEDs.

    3. You're backwards on the series/parallel functions. Series adds the voltage of the individual cells, parallel adds the amp capacity of the individual cells.

    4. A toggle will work. You will most commonly find SPDT toggles will be center off. That would give you a Low,Off,High type operation.

  3. #3

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    Thanks Vanc.

    I take it you are from Vancouver? I lived there (Burnaby) back in 1989 for a year. Loved the place and that's where I took up MTB on the trails around SFU and UBC. Oh... and around Whistler in the summer months!

    1. Got it now I think. If I was only using a single power mode I'd go to the chosen terminal. However, as I am going to use the dual high/low option I need to run the +high and +low from the toggle switch +/- terminals.

    2. I am not sure where to find the Vf of the 3xLEDs but the specs say: "output voltage is 2.0-11.7V for 1-3 3W LEDS". Specs also say: "perfect driver for a 12V power supply". So I'm thinking a 14.?V battery pack.

    3. Woops! OK... so to get over 14V I need say 4x 3.6V cells in series. I if use 4x of the SW-AA02 3.6V Batteries oft the Cutter site with a nominal capacity of 2400mAh I would have a battery pack of 14.8V with 2400mAh. If I use 2x parallel sets of 4x series cells I would have a battery pack of 14.8V and 4800mAh. Am I on par here?

    4. The toggle seems like a plan. Would make quick flicks from low <---> high pretty easy (this light will be bar mounted). Would flicking past the 'off' position each time cause any issues to the light or batteries?

    Cheers again for the input Vanc.

    Aaron.

  4. #4
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    Quote Originally Posted by Aussie_Aaron
    Thanks Vanc.

    I take it you are from Vancouver? I lived there (Burnaby) back in 1989 for a year. Loved the place and that's where I took up MTB on the trails around SFU and UBC. Oh... and around Whistler in the summer months!

    1. Got it now I think. If I was only using a single power mode I'd go to the chosen terminal. However, as I am going to use the dual high/low option I need to run the +high and +low from the toggle switch +/- terminals.

    2. I am not sure where to find the Vf of the 3xLEDs but the specs say: "output voltage is 2.0-11.7V for 1-3 3W LEDS". Specs also say: "perfect driver for a 12V power supply". So I'm thinking a 14.?V battery pack.

    3. Woops! OK... so to get over 14V I need say 4x 3.6V cells in series. I if use 4x of the SW-AA02 3.6V Batteries oft the Cutter site with a nominal capacity of 2400mAh I would have a battery pack of 14.8V with 2400mAh. If I use 2x parallel sets of 4x series cells I would have a battery pack of 14.8V and 4800mAh. Am I on par here?

    4. The toggle seems like a plan. Would make quick flicks from low <---> high pretty easy (this light will be bar mounted). Would flicking past the 'off' position each time cause any issues to the light or batteries?

    Cheers again for the input Vanc.

    Aaron.
    Actually I am from Vancouver, Washington. That is a small city across the river from Portland, Oregon.

    1. Sounds like you have it.

    2. LED Vf is the voltage required to cause it to conduct. Each LED has its own Vf but CREES seem to average around 3.2V. LEDs can be connected in series or parallel. I suspect that the cutter triple is series wired for this kit. That would give you around 9.6Vf. The driver will keep your current regulated until battery voltage drops below 11V in this case.

    3. Correct. The 4 cell pack at 2400mA will give you a runtime well in excess of 2.5 hours at full power.

    4. I have never used this driver but can not imagine why there would be any problem with switching through the OFF position. The flicker might be annoying and worth figuring out a different switch setup.

    The dual output settings of 80 and 700mA may not prove very useful. I think that the light output at 80ma will be so low as to be unusable for riding. After looking at cutters site describing this driver, I wonder if a pot wired across the cut in trace C might allow variable dimming. It would be worth running by George at TaskLed.

  5. #5

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    Great stuff mate. I appreciate the time taken.

    If the 80mA option seems the light output will be too low to be functional and you suggest I could get over 2.5 hours on 700mA (which is plenty of runtime for me), I'd be inlcined to just go the higher option (and maybe run a pot like you suggest). My question is about light brightness.... I have read a few posts were light output is so high that it can blind oncoming walkers, riders and cars. I have also experienced this a few times myslef on the trails. Assuming this light has the output claimed by Cutter of 500 lumens, where does that kind of output stand in terms of its ability to blind oncomers?

    Assuiming I use a pot... What if I cut trace A and C to make it a single 700mA driver, then also cut B and run the pot across that cut? Add just a simple on/off toggle. Would that give me variable light output ranging from 700mA and down?

  6. #6
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    500 lumens is bright enough to blind them but if you've got a helmet light just don't look them in the eye or if you're talking to them put your hand infront of the light (discovered this talking to a policeman) one night. 500 is plenty to ride with, but once you've started you'll be lying awake at night planning 3000 lumen badarse lights just for the sheer he11 of it

  7. #7

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    Ants... Already planning my friend!

    Just have to learn a few things first on this easier project.

    Warming up the mill and lathe for the next one ;-)

  8. #8
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    Quote Originally Posted by Aussie_Aaron
    Assuiming I use a pot... What if I cut trace A and C to make it a single 700mA driver, then also cut B and run the pot across that cut? Add just a simple on/off toggle. Would that give me variable light output ranging from 700mA and down?
    This driver looks pretty interesting as far as modifying it goes. Changing the pattern of cut traces A and B with a switch would probably give you the ability to switch between all 3 output levels. It looks like all the traces do is bring different resistors into the circuit. Still worth an e-mail to George at Taskled to verify before smoking it while experimenting.

  9. #9
    Randomhead
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    I bought one of these drivers with a kit from cutter. I would be interested in knowing if anyone gets a switched configuration working. I don't really have a light planned for it, but my usual bad logic said it might be useful to have around.

    I just tested the driver. I didn't realize my bench supply would only put out 250mA, and thus it was current limited in the standard 280mA configuration. The driver seemed to run fine below 5V, which is all the PS could drive at that current. It would be really nice to be able to switch between 250 and 700mA. I have a fairly large stack of 2S1P 700mAh lipoly battery packs that would be nice to use with this, and it seems like they will work.
    Last edited by unterhausen; 04-28-2009 at 02:49 PM.

  10. #10
    Randomhead
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    I was just looking at the pattern to cut traces, and I'm having trouble figuring out how a switch would work. I guess I'll have to put the circuit under a magnifying glass.

  11. #11
    rjd
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    Looks to me like its 80ma and 750 or 350 etc

    I dont think you configure it to switch between 350 and 750 on its own.

  12. #12
    Randomhead
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    apparently the trace cutting procedure changes a control voltage. It stands to reason that the control voltage could be changed by a switch or pot.

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