Calling out to Weezard for LED advice

[Weezard]

Anyone have any suggestions for a quick cheap way to safely power 12 ledengin 5 watters? 4 blue 3.6Vf, 4 red 2.5Vf, 4 deep red 2.8Vf. They are all 1000mA.

I was thinking 3 series strings in parallel to the PSU? But I am not sure how to do the circuit calcs. The online calcs wont let you mix and match that way.

There's a reason fo' dat.
No can!

Blues wants, 14.4V.
Reds, 10.0
Deep reds, 11.2

However, using an LM 317 current limit supply will only need about 2V.
headroom.
Find a 40V. 2A supply and throw 1. cheap, 3 terminal chip an; 1, resistor at it and you are done.
Need details? Jus' ask.

Aloha,
Weezard

[mx4intx]

There's a reason fo' dat.
No can!

Blues wants, 14.4V.
Reds, 10.0
Deep reds, 11.2

However, using an LM 317 current limit supply will only need about 2V.
headroom.
Find a 40V. 2A supply and throw 1. cheap, 3 terminal chip an; 1, resistor at it and you are done.
Need details? Jus' ask.

Aloha,
Weezard

Sounds like you are saying throw 40vdc into a lm317 and run it all in series?

[mx4intx]

I was also wondering how bad ass a heatsink would have to be to dissipate the heat if these were all mounted tightly packed together to act as more a single source of light?

[Weezard]

Sounds like you are saying throw 40vdc into a lm317 and run it all in series?

Zackly!

Try it, you'll like it!

Aloha, Weeze

[mx4intx]

Mahalo Weezard! That makes it simpler. I have the LEDs in hand but nothing else yet. I'll be sure to post it all when it's done. I have been reading LED threads all over including this one twice and you've been quite the inspiration in a few of them.

[khyberkitsune]

I was also wondering how bad ass a heatsink would have to be to dissipate the heat if these were all mounted tightly packed together to act as more a single source of light?

300w packed into an 8.5x16x2.5 inch space took quite a hefty heat sink and heat plate and fans for me to get it stable and operational.

[Weezard]

Mahalo Weezard! That makes it simpler. I have the LEDs in hand but nothing else yet. I'll be sure to post it all when it's done. I have been reading LED threads all over including this one twice and you've been quite the inspiration in a few of them.

I noticed that you did some reading before posting.
Can't tell ya how much that pleases me!

Mahalo nui right back atcha, brah.
You slogged through all dat mess, twice!?
You deserve a synopsis.:jointsmile:

The LM 317 is an easy beastie
Just hang a 1 ohm, 10 W. resistor in series with your load and tie the load end of the resistor to the Adj. pin.
[attachment=o265844]
It's actually a voltage regulator, but if we pull current through the resistor, the 317 will try to maintain a 1.2V. difference between its output pin and it's adjust pin.
To do so, it is forced to regulate the current for us.

Automagically adjusts all the junction drops for us too.
1 amp. is 1 amp.!
Or, in this case, ~1.25 A.
Max onna regulator, and emitters, is 1.5 Amp
I use a heatsink from a stereo power Ampilifier that I spotted in a dumpster.
One channel was fried, but the heatsinks were beeg!
And free!:hippy:
[attachment=o265845]
And, as it turns out, jus' da right size with a small fan.
I use a single muffin fan to cool the chips and the pwr. supply module.
[attachment=o265847]
Stripped them, polished, drilled, bolted 10. deep red 5W, stars onnem and 3 Royal blue, 5W. Ledengins.
Used dropping resistors for the first grow, then realized it was a great budding light and got serious about safety and longevity.

Retrofitted some cheap current regulation and relaxed a little.:rastasmoke:
[attachment=o265846]

Loaned it to a friend when I built da 2 beeg lights.
He grew fat buds with it!
Now it's back in harness for my momma plants.

Now, aintcha glad ya asked?

I'll be followin' your log.:thumbsup:

Aloha,
Wee 'zard

[mx4intx]

Nice! I am glad I asked. My big problem is finding a cheap small 40V 2A supply. I already have a homeless 19V 2.1A laptop supply. I may end up just splitting the blue and red into two independant strings.

[Weezard]

Nice! I am glad I asked. My big problem is finding a cheap small 40V 2A supply. I already have a homeless 19V 2.1A laptop supply. I may end up just splitting the blue and red into two independent strings.

That's what I ended up doing on one of the arrays.
Used dropping resistors.

The laptop supplies are excellent and can mount piggyback on the 'sink.
Hope ya no mind if a watch.

Aloha,
Weeze

[mx4intx]

I think that this will take care of any cooling issues

used Aluminum Heat Sink 9 7/8" x 6" x 2 ", 388sq Dissip - eBay (item 180626613955 end time Feb-22-11 11:05:02 PST)

And I know I have some old pc fans laying around too. This will take care of the 24V

SCHIELE SYSTRON PS 24V 2.423.417.00 POWER SUPPLY - eBay (item 280618533522 end time Feb-18-11 10:27:33 PST)

Wont be too much longer before I start building this thing I hope.