What to do with old leftover Cree XRE's?

Flashlight Modding and DIY Parts
1

Like many of you, I've got a ton of leftover Cree XRE's just sitting in my parts bin. I don't plan on putting them in lights since most have been swapped out with higher output emitters. So I have an idea to create an LED strip using 15 XRE's. I would like to power it from an AC outlet and drive them at ~350mA constant current. Power consumption will be 18.9W (15 LEDs x 3.6V x 350mA)

Here is diagram of what I'm thinking about.

Up to this point, my only experience with drivers has been restricted to the DC kind that are powered directly off batteries (NiMh, Lion, et) However, I would like to have this be a plugin kind, so I need a driver than can handle 120V AC input and deliver DC output sufficient to drive the LED's at ~350mA. Based on the power consumption at that drive current, I'm guessing I'll need a 20W driver. I have no experience in this area and would like to reach out to anyone who can offer some guidance. I found this one from DX that seems to have the proper specs. Would this work? Are there others I should consider? I don't want to spend tons of $$ on this, but I also want to build something safe of course.

2

Input voltage on that is 180-240V, so not rated for US voltage...

Drive them all at 3w?

http://www.fasttech.com/products/1612/10001426/1110800-100-240v-13-17x3w-high-power-led-driver-transforme

Here's one from DX that appears to be proper specs...

http://dx.com/p/jr-9-15-15w-led-constant-current-source-power-supply-driver-85-265v-186293

Another that might work?

http://dx.com/p/waterproof-25w-power-supply-constant-current-source-led-driver-yellow-ac-85-265v-181256

3

Thanks very much for pointing out the voltage range on that DX driver, I missed that.

Those others look promising.

-The FT driver would work but does push them harder than I wanted (650mA)

-The DX 9-15W driver has the correct drive current I want

-The other DX 25W driver seems good too, but does not list the drive current in the specs.

Thanks for the suggestions keltex78!

4

It does, look at the photo of the driver; (If you trust DX to not change products) 300 mA.

5

You’re putting them in series right? Make sure the driver lowest V-out matches your total Vf (in your 350mA case, it would be 3.3V per LED per CREE spec).

To use the one from DX above, it only step down lowest to 50V so you need around 16 XREs in series to match that.

6

Correct, I plan to wire them in series.

IIRC, XRE's have Vf of 3.6V, so 50/3.6=13.9, so I would need a minimum of 14 emitters which I do have.

7

Look at the fish tank forums for more info on this kind of set up....

http://www.ledgroupbuy.com/how-to-builds/

lots of how to....and info on these types of drivers.

8

Thanks for the link!

9

I would not use power supplies from chinese websites, many of HKJs usb power converter reviews have shown they are not built safely enough to get certified. Last thing you want is a fire and then the insurance company saying we won’t cover you because you used unsafe electronics

Spend the money on a name brand supply from a reputable website

10

What would you recommend then?

11

its been a long term project of mine to find a suitable power supply for an xm-l LED, no luck yet, or i should say no luck for under $40.

Constant current supplies for 6V (to drive an mt-g) would be a better bet, i’ve been looking into a lot of mean well power supplies from mouser, but nothing i am wanting to buy yet (not meant as an endorsement, since i am not very knowledgeable about them)