Outdoor LED flood light with Cree P4s

We need a flood light for our back yard. My Mum wants to use a few of those 300W halogen flood lights, but I wouldn't hear of it. At least, not until I'd tried making something more sensible.

I was thinking that I could use 15 of these emitters:
http://www.dealextreme.com/details.dx/sku.2134
as they are are relatively cheap and the WD bin should be quite pleasant for outdoor lighting.

The area to light is about 4m by 10m in size. I would like to have 3 fixtures, each with 5 of those LEDs. I'm not sure if that will be bright enough, but if those fixtures work, I can always just build more. Constructing the fixtures shouldn't be hard. I can build a back plate out of sheet metal cut to the appropriate size, perhaps with some old CPU heat sinks thermally bonded to the back if necessary. I won't use optics, I'd leave the emitters just bare, perhaps putting a thin frosted glass in front of them so that they don't cause discomfort to the eye.

How to drive them is a question I don't know how to answer as yet. The input obviously has to be 240VAC (mains supply), and if I am to use 5 of them in series I need to convert that to about 19V and 1A. Should I build my own adapter for this or can you buy a driver that can deliver that off the shelf? I'd prefer to just buy one.

Also, how much light can I expect out of 5 of these emitters? If 5 isn't enough, then I could put 10 in each enclosure. I was thinking of building a 12 emitter single flood light for the whole area, but that wouldn't light things up as evenly. I think that 15 of these emitters in 3 fixtures around the space should be enough, but I'm open to advice from those here who are more experienced than I.

I would probably use a computer power supply to change the voltage down to 5V or 12V (not sure what comes out of those cables, except that it's DC), and then you can connect the LEDs from that.

There are many ways to do this.

There are some AC drivers on DX but I don't know if I'd trust them (maybe fire hazard if left on)

Look into the LED-TECH lighting sites for 240V Drivers
Deal Extreme has drivers as well but they are low current (320ma)

As far as brightness 30 XR-E Q5 would be as bright as a 300W halogen rated at 6000lm
If you are looking for that level of light buying SSC P7's is more economical.
Driving 7 at 240V 2.8A and heatsinking is the tough part.
Use this DX driver to run one P7 at 2A

kuksul08 said:

There are some AC drivers on DX but I don't know if I'd trust them (maybe fire hazard if left on)

Click to expand...

I have used the DX GU10 700ma drivers and no sign of burning in the last 4 months with less than Great heatsinking, ust watch out for grounding the driver to the housing as they aren't insulated (big heatshrink hose fixes this problem)

You can't beat Metal Halide. I've got some Philips ones that take about 70 Watt, light output is more like a 500 Watt halogen.

However I'd use the 12v 3 watt AC/DC drivers from DX, a suitable 12v transformer and 3 Q5s per fitment. It will keep costs down and should be enough light. At our stables I only use 4 quarter watt in each stable and about 8 more around the place (all in groups of 2 with an LM317 current regulator) powered by an old 12v car battery. I two rebels (at 700mA) in a small flood light to iluminate the field around the stables. Its enough light to see to feed the horses at night and the battery last much longer than my last bad idea (mains invertor and energy saving bulbs).

Computer power supply running series of 3 Crees with AMC7135s limiting the current. If the duty cycle is less than a half hour on/hour and a half off, you can mount the LEDs to rectangular masses of aluminum which will absorb the heat.

You could use some of these http://translate.google.co.uk/trans...=s&rls=org.mozilla:en-GB:official&hs=Jmg&sa=G availble here http://www.kaidomain.com/ProductDetails.aspx?ProductId=5639
The 18W 700mA version will happily run an mc-e or p7. It's also IP65 rated so it should be fine to use outside I have one already and it's an extremely simple, cheap option imo.

Paul.

Paul Baldwin said:

You could use some of these http://translate.google.co.uk/trans...=s&rls=org.mozilla:en-GB:official&hs=Jmg&sa=G availble here http://www.kaidomain.com/ProductDetails.aspx?ProductId=5639
The 18W 700mA version will happily run an mc-e or p7. It's also IP65 rated so it should be fine to use outside I have one already and it's an extremely simple, cheap option imo.

Paul.

Click to expand...

Thats great for a Cree MC-E but will burn a P7 out instantly. Not the current but the voltage. A P7 can only handle 4v and this driver starts at 12v.

If you order Cree MC-E on a MCPCB Serial wired this will work great.
Cutter is a great supplier but it may take time to get the products you order.

Sorry, my bad . I forgot the P7 is not individually addressable like the mc-e. I ordered my M bin mc-e from Cutters as it happens too, shipping did take a while but it did get here and the items I ordered were all good quality :twothumbs
I took the setup I have to a friends the other night as it happens, he is also keen to light a yard much bigger than 4x10m and replace 2x300W halogens. 1xmc-e lit the whole area adequately enough to avoid parked cars and not fumble in the dark. He wants me to make 2 up for him and rig them to PIR's
A bare emitter with some frosting to take away some of the intensity of the emitter is the way I am going. Very simple to make with a pc heatsink and some thermal epoxy.

Paul.