Milad's 72in LED build

[mseepman]

Looking forward to seeing this...I am planning an LED build myself for my 290G peninsula once I finally get the damn house built.

I was planning on doing a blend of CW and RB crees but after researching for countless hours, it appears to me that there is a real need for some Neutral Whites and even a few standard blues in the mix to give you the coloration that we are used to with MH and or T5.

Where are you getting your heatsinks? Where are the big meanwells coming from? Are you planning to balance the forward voltage on your parallel setups or are you just going to keep the voltage low enough to handle an issue if it arrises?

I plan to do about 200 LED's and that would mean a lot of the small ELN meanwells which is a problem. My issue is that all the threads over on RC seem to put the fear of GOD into people who plan to go parallel on their LED setups rather than serial.

Looking forward to hearing how you plan to do all this.

[Milad]

from my first post you will see im going 2 drivers only for all 144 leds.
one for CW and one for RB so i can dim them seperatley

im actually doing a diagram right now to handle any issues with the parallel design, it should be fail safe. I should have it up within next couple hours.

Drivers are coming from cdiweb.com
Heatsinks are coming from heatsinkusa.com
Extra odds and ends are coming for digikey.ca

ill be posting links to each of the parts too for others reading.

[Milad]

So here is the wiring diagram and parts list

The resistors are there to easily measure the amps since this is a parallel design.
Fuses are in for "o ****" protection
Terminal blocks for ease of wiring

Doing this setup doesnt really give me plug in play modules but rather a full 72in fixture.

Resistors x 12: $1.05 ea
http://search.digikey.com/scripts/Dk...me=UB5C-1.0-ND

1A Fuses x 12 (for Royal Blues): These are 1A. And could be used in most cases in 700ma up to maybe 900mA setups. $0.83 ea
http://search.digikey.com/scripts/Dk...ame=F3169CT-ND

1.5A Fuses x 12 (for Cool Whites): could be used in most cases in 1.2A up to maybe 1.4A setups. $0.83 ea
http://search.digikey.com/scripts/Dk...&name=F2319-ND

Terminal Block x 4: These are 12 position $3.80ea
http://search.digikey.com/scripts/Dk...name=A98510-ND

Terminal Block Jumper x 20: $.025 ea
http://search.digikey.com/scripts/Dk...&name=A0139-ND

10x10 Heatsink x 3 $31.17 ea
http://www.ledgroupbuy.com/products/...x-10-inch.html
*note might be changing this due to weight issues

****NOTE THIS DRIVER HAS CHANGED BECAUSE IT WILL NOT DIM UNDER 50%**********
Cool white dimmable driver (HLG-240-42B 42v 5.72 amps) $118.31
http://wattsupply.com/s.nl/it.A/id.3056/.f

****NOTE THIS DRIVER HAS CHANGED BECAUSE IT WILL NOT DIM UNDER 50%**********
Royal Blue dimmable driver (HLG-240-54B 54v 4.45 amps) $118.31
http://wattsupply.com/s.nl/it.A/id.3056/.f

#6-32 3/8 Length Nylon Screws (100pc) x 4: 4.64ea
http://www.smallparts.com/nylon-mach...qid=1291591373
or More expensive but in Canada:
http://search.digikey.com/scripts/Dk...l&name=H556-ND

#6-32 Tap x 1: 11.25ea
http://www.smallparts.com/butterfiel...e_name=%236-32
*I might buy this locally and order the nylon screws through digikey

Thermal Grease 2.5g x 5: 4.83ea
http://www.ledgroupbuy.com/products/...trix-2.5g.html

22awg 600v pretinned stranded wire: $7.50 50ft
http://www.ledgroupbuy.com/products/...600-volt).html


LEDs
XP-G cool white in 10 LED series (http://www.ledgroupbuy.com/products/...ool-White.html)
XP-E royal blue in 14 LED series (http://www.ledgroupbuy.com/products/...oyal-Blue.html)


Ill probably end up buying 3 times as many fuses just in case.

wiring on between LEDs is 22awg
wiring from driver to blocks is 20awg

[mseepman]

Wow, you did a really nice job putting that diagram together.

I was hoping to do the parallel thing but avoid the resistors and fuses as I start to feel like it's getting past me in my electrical knowledge. Hadn't thought of doing a terminal block but it's a really good idea.

[Milad]

the resistors and fuses are simple once you know why you are putting them in and undersatnd whats happening on a parallel string.

ill try to explain it.

most of the simple designs you see are one driver per 12 LEDs
These are usually powered by something like the meanwell LPC-35-700
This driver puts out up to 48V and .700amps

the LEDs are rated to have about 3.5 volts each and .700 amps per series.

12LEDS * 3.5ea = 42V. The driver above will adjust itself down to 42v

so the above driver can only handle one series (.700amps) and 12 LEDs (48v).

Now lets say you got a big bad driver that does 2.1amps and 48V

So now you can only still have series of 12 LEDs (48v). But since you have 2.1amps you need to balance that out between 3 series of 12 LEDs which gives you .700 amps per series.

The reason you start needing resistors and fuses is to be "safe"

So, if for watever reason one of those 3 series decides to stop, and other two keep running, you are dividing 2.1amps between 2 series instead of 1! Thats 1.050amps per series. If the LEDs cant handle it, boom goes the LEDs. This is why you put a 1amp fuse in before each series. As soon as one series goes, the 1amp fuse blows and your LEDs are safe.

So what is the resistor for?
Well for you to measure the amperage on each series you need to un-solder and put a multimeter inline with the leds. Well of course this sucks. If you put a 1ohm resistor at the beginning of each LED series then you just measure across the resistor while its inline and it will tell you the amperage.

From my understanding the amperage can vary per series so you want to switch LEDs out and get them as close as you can to each other. Over time it can change also, so having the resistors in there for quick tests works great.

[mseepman]

Thanks for the quick explanation. I will end up putting in both the resistors and the fuses now that I know where to get them and why. You should make sure you take some detailed pictures of your wiring to the terminal blocks, how the jumpers are setup and your wiring of the fuses...(so that I can copy of course)

Any luck with the info from ETG on Neutrals and Blues?

[StirCrazy]

why did you decide to run them at 0.7amp instead of 1 amp? just curious.

Steve

[abcha0s]

<deleted post - may have contained inaccurate information - sorry!>

[mseepman]

I understand your thoughts on Ohm's Law and it seems right. The issue seems to be between the theory and what really happens when a string fails. Others who have done parallel builds have found that without the fuse, the amperages accross the remaining strings increase and either shorten the life of your LED's or destroy them. Could this be based upon how the first string failed? Maybe the worry is if the LED fails open?

[GMGQ]

Milad,

Am I correct to assume that on the left side of the terminal blocks, they are all jumper together?

Thanks.

Originally Posted by Milad

So here is the wiring diagram and parts list
wiring on between LEDs is 22awg
wiring from driver to blocks is 20awg