Multichip LED build questions

[joelbegt]

Thank you so much for your help, I hope i am not asking to many questions.

how does wiring in series compared to parallel change things when selecting a driver. I am looking at separate drivers for each 50w or I can find larger drivers that may work to fire all on one driver. It also looks cheaper to get one driver rather than multiple ones.

Hypothetically lets say I want to have 4 of the following leds one only one driver:

50W
Forward current:2200ma
Forward Voltage:24-26
Color 12000k

Am I just looking for a 200w driver rated to 24-26v and 2200ma?
Do things change if I want to run in parallel to prevent a light out issue if one chip dies?

Thanks Again!!!

 

[joelbegt]

Forgot to ask what you thought of these hybrid multichips I keep seeing. Do you think the half blue half white would blend or would there be a visible line if using these?

 

[tat2z_21]

It is possible to wire them in parallel, but you have to remember that if you blow one string then the other string gets the doubled current which would obviously blow that string as well and cause other issues. Adding a inline fuse might protect against that but I personally believe that series wiring is best. If a light goes out then the string goes out.

You could look at one of these. It would fire two of your 50w's......

Meanwell Power Supply Products

 

[tat2z_21]

LED's in parallel can be done as I said before, but what happens Is one single LED may have a forward voltage of 24.4 and the other string of LED's might be at 24v.
So off of the information given we can figure out the internal resistance of the LED's.

R=I/E
2.2a/24v = 10.9ohms
2.2a/24.4v = 11.09 ohms

Knowing that voltage takes the path of least resistance. Which means that string 1 of 24vdc rated at 10.9 ohms would take most of the current and eventually burn out. Then creating a situation to where all of the amperage is running through the other. You can try to buffer this with current Limiting resistors but it would still be a potential disaster.

 

[joelbegt]

So really running in series will protect the other bulbs if a failure occurs. So if we take the example above and wire them in series are we looking for a 100w driver with 24v at 2200ma?

 

[BigAl07]

What about "inline" fuses? at a recent LED talk I went to the builder went to great lengths to make his system "Blow Proof" and he indeed wired all of his in parallel. He said worse case scenario he had to locate and replace a single fuge rather than a whole array of LED and he was able to run 2x as many off of a single driver over running in series.

 

[BigAl07]

Disregard part of my question. Obviously I wasn't up to date on this thread... OOPS!!

 

[tat2z_21]

You are correct about the inline fuses though. You could put a 1a fuse inline with all strings. This would work.

 

[BigAl07]

You are correct about the inline fuses though. You could put a 1a fuse inline with all strings. This would work.

Depending on the design this could add a good deal of work and complexity to the array but it could also save the array in the event of a mishap. Not only during an LED failing but also if you were to mistakenly touch your meter to the wrong wire etc during set-up.

 

[slick]

Multichips are very inefficient compared to most single diode LED's. Why not just use single diode crees or luxeons. You can drive a cree XM-L at 9w max..... You want alot of LED's in a small area? Use 3-up LED's. Then you will have the power with less heat and less power consumption. Check out the nano pulsar on this page: http://www.nano-box-reef.com/

 

[Guerry]

Here's an exaple of one of my fixtures these are run in parallel strings using resitors and fuses

 

[BigAl07]

Guerry that's a VERY nice and neat setup! It looks like you do really good work!! Way to go

 

[Guerry]

Guerry that's a VERY nice and neat setup! It looks like you do really good work!! Way to go

thanks, it only takes alittle longer to do it right some fokes just get in alittle hurry to see the end resualt

 

[tat2z_21]

Guerry that thing is nice. I was drooling over it in your thread. So with them in parallel have you noticed one string brighter then the others. Also are you using a 1 ohm resistor for each string?

 

[tat2z_21]

Multichips are very inefficient compared to most single diode LED's. Why not just use single diode crees or luxeons. You can drive a cree XM-L at 9w max..... You want alot of LED's in a small area? Use 3-up LED's. Then you will have the power with less heat and less power consumption. Check out the nano pulsar on this page: Nano Box Reef - Custom LED Aquarium Lighting

You are correct that they are not as efficient as a couple strings of 3w's. But I am a tinkerer and want to see what I can come up with. Mojo was kind enough to drive all the way up to Whidbey to check PAR levels. Not quite what I was hoping for but who knows. For some reason they had the same reading at the bottom as my 250w halides. Which was not much. I want to say it was somewhere around 100 PAR.

 

[Guerry]

Guerry that thing is nice. I was drooling over it in your thread. So with them in parallel have you noticed one string brighter then the others. Also are you using a 1 ohm resistor for each string?

Thanks As far as brightness I haven't had a problem, you can balance your emitters if so not all emitters consume the same amount of power so it would just come down testing draw for each and moving them between strings for power balance. The resistors that I use are 5watt/1ohm

 

[tat2z_21]

Awesome.

I would love to pick your brain sometime on this. When are you and Mojo knocking out that monstrous LED build

 

[Guerry]

Awesome.

I would love to pick your brain sometime on this. When are you and Mojo knocking out that monstrous LED build

you'll have to watch his thread, but I'd be willing to bet there's getting ready to alot of action there