Driver suggestion to run 4x CREE XML

hi all

I am on my way to make a flashlight for my Bicycle i almost got everything except the driver/drivers

I will be using 4 Cree XML U3 i want to run every one of them not less than 2500 mA so would any one please help and suggest me a Driver to run the 4 of them ?

Is this for on road or off road. If on road that's really overkill.

No one can answer without knowing what battery you are using.

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I will be using 3 li-ion 18650 battery in series that will give me about 11.1 volts i just have plenty of 18650 battery by another mean i will use laptop battery i just know a place that sells a working used laptop battery for less than a one dollar don't ask me how ?:thumbsup:

That configuration will give you brightness way above what car headlights put out. And without professional beam design, much of that light will end up in the face of oncoming drivers. That is probably NOT in your best interest, safety-wise. If you blind oncoming drivers, they will be MORE likely to hit you, not less. It's a lose-lose situation.

If you want to learn about safety while driving a vehicle (and peripherally, while riding a bike), read in the automotive forum. There's a lot of discussion there about both safety and legality. While legality may or may not be a concern to you, being on a bicycle, most of the legal issues are driven by safety concerns, which should be of major concern to you.

Of course i do care about safety and legality and i will not make something to harm other people the beam will be directed at the ground not just in front of me blinding every one

still want a driver suggestion i am really very confused

If you wire them up as two parallel strings of two XML's in series, you would need a total of 5A at about 6.7v. I haven't looked at the details, but it looks like TaskLED has a couple of drivers that might work.....
http://www.taskled.com/compare.shtml

The H6CC or h6Flex look like possibilities.

30W of LED is huge for a road bike. Not that huge for offroad riding, as I understand it.

I might suggest that you use more than 3x 18650s. Even brand new cells would give you nominally around 1 hour run time. Used and/or old cells will have lower capacity, and pushing them above 1C discharge rate will further reduce the capacity. I would think about using a 3S2P configuration (3 in series, 2 in parallel, or two strings of three, connected in parallel).

Steve K's suggestion is a good one. Taskled makes very good drivers, and those are the two you want to look at. Also, you might consider two of SKU 162784 or 57779 from dealextreme.com. The quality is poor, but the price is cheap, so for messing around they might be good.

thanks Steve K for your suggestion taskled always have good drivers but i don't think it can ship to Egypt

thanks DIWdiver for your input, well i will be using three strings of three connected in parallel , and about this driver 57779 from dealextreme.com i don't think it can run 4 leds ? do you know its output voltage ?

No matter how you point that light it is overkill. One XML is more than. Enough for a road bike.

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what about this one http://www.aliexpress.com/item/Boost-Buck-3-18V-3-Modes-24mm-30W-Circuit-Board-Driver/533321749.html ?