Outta my league DIY LED

metalsniper · Jan 12, 2012

Yeah, you got them right on. Thanks! I should be building a test rig soon so I can practice my soldering and circuitry as well as drilling and tapping. Just waiting on a drill press and circular saw from my father in law. Also waiting a bit for school to quiet after the start of the semester so I can get into the build.
For testing purposes I plan on getting a few royal blues, a few whites, a set of true purple, deep red and turquoise. I want to mess around with color mixtures to see what looks the best. Supposedly a RB with a turquoise and deep red will look white but give the same pop that the three give individually.

Any suggestions on additional leds I should get to try. I was thinking of getting the greens but with the small area on the test I think it would over power everything else.

Onedesign1 · Jan 12, 2012

I've never played with colors other than different temp whites, royal blues, blues, greens, and reds. Beware the reds are what are over powering though. Interested to see your results. Where the heck are you getting a turquoise and why would you think of that?

metalsniper · Jan 13, 2012

I was looking for something to fill the color gap between the blues and the whites around 500nm and I found cyan on the cree site. Then when I was looking for somewhere that carried them I found turquoise on groupbuy. Looking into it a little more the three are supposed to equal out to white so I hope that with them together I won't get red overpowering anything else. Its just one of many things I wan't to try before I settle on my final led breakdown. I want to try the green but I don't know if with such a small trial light they will be too powerful.

metalsniper · Jan 15, 2012

Okay, so I need a little input. For my little demo unit I want to make it so the drivers and dimmers all run off of one plug, what kind of drivers should I use? I'm trying to keep the price low but with all the lights I'm getting to test its already 150$. Should I go with buckpucks and a laptop charger that gives 18.5V 6.5A or should I go with the meanwells and go strait ac? I'm thinking use buckpucks with the laptop charger and split it into the case with a 10K pot to dim one leg down to 10V then two 10K pots to run the dimming circuit from the other 10K. Does this seem okay? Should I get the 1000mA or the 750mA or one of each?

Does anyone have any input as to the lowest prices to get an assortment of leds and drivers and pots and power supplies?

Onedesign1 · Jan 16, 2012

I have not used the buckpucks but the Meanwell ELNs are around $30 and you can gang them onto 1 AC plug no problem.

jtl · Jan 18, 2012

Not wanting to hijack someones thread but I guess I sorta am. How many POTS can be on a single ELN 60-48 and how many Cree XPG, XPE and Royal Blue (one color on each of three ELN's). Would like to get 14 of each color.

Onedesign1 · Jan 18, 2012

jtl said:
Not wanting to hijack someones thread but I guess I sorta am. How many POTS can be on a single ELN 60-48 and how many Cree XPG, XPE and Royal Blue (one color on each of three ELN's). Would like to get 14 of each color.

I may be misunderstanding your question but you can only dim an ELN as a whole so only 1 POT per ELN. You can gang multiple ELNs on a single POT to dim them all together.

You can run 14 XP's in series on a single ELN 48. You can parallel them which divides the current by number of strings. ( I have run 28 via 2 strings of 14).

Then you say you want "(one color on each of three ELNs)".... so not sure what you are wanting to do.

You can also start your own thread so as not to hijack Metalsnipers but thats his call.

jtl · Jan 19, 2012

Thanks for the response. The thread has been very helpful but I did start a new one to deal with my particular situation and could sure use some advice.
John

metalsniper · Jan 19, 2012

Hey, I don't mind. Any info we can get out in the open is best.

In other news I have ordered supplies for a trial build including turquoise, deep red, blue, royal blue, true violet, cool white and neutral white. I also ordered two buckblocks at 1400 mA and 1000 mA.

Most of my order arrived last night and I have a few photos that I'll post soon. The purpose of this is for testing color combinations and mixing.

These will be mounted on a 4*9 inch 1/4 inch aluminum attached to two 3*4 copper Pc heatsinks.
For my testing I'm going to try clusters of:
red, turquoise and royal blue
Blue, violet and royal blue
As well as comparing to individual leds of different colors.

This last one is a bit of a "back of the envelope" aproximation of how I think I will end up setting up the practice fixture. For first test the corner clusters with be blue, violet and royal blue while the middle is the turquoise, red and blue. The V is composed of cool white and neutral white alternating.

Of course, I haven't gotten my drivers or royal blue leds so they are missing from this mock-up.

Onedesign1 · Jan 19, 2012

excellent....love experiments!

metalsniper · Jan 20, 2012

On a happy note I got my drivers tonight from ledsupply and got them all wired up to molex connectors for connecting to the led strands and dimming strands and a 4 set terminal block to handle the power supply wires with a jumper wire connecting the two respective strands. I have a couple of photos but, alas, no means to upload them tonight so I will get them up tomorrow probably.

Also, the always wonderful fiancee is bringing me a drill press tomorrow so if I can get the local machine shop to cut my aluminum to size I will be able to start drilling and tapping.

It seems that all I am missing now is a soldering iron so I can start actually connecting these leds.
On that note, does it seem possible to split my power supply inlet into thirds, one for each driver and one that passes through a dimming pot to reduce it to 10V then split again to run the dimming circuits for each driver?

I need advice too as to where I need to put fuses and resisters so I can protect my leds and to measure my current.

metalsniper · Feb 1, 2012

So I've moved forward but I'm having an issue, I'm only getting half of the current I should be from my buckblocks. I have a set of parallel strings in the 1400mA driver and I'm getting about 300mA across each string. any ideas?

KJAG · Feb 1, 2012

metalsniper said:
Hey, I don't mind. Any info we can get out in the open is best.

In other news I have ordered supplies for a trial build including turquoise, deep red, blue, royal blue, true violet, cool white and neutral white. I also ordered two buckblocks at 1400 mA and 1000 mA.

Most of my order arrived last night and I have a few photos that I'll post soon. The purpose of this is for testing color combinations and mixing.

These will be mounted on a 4*9 inch 1/4 inch aluminum attached to two 3*4 copper Pc heatsinks.
For my testing I'm going to try clusters of:
red, turquoise and royal blue
Blue, violet and royal blue
As well as comparing to individual leds of different colors.

This last one is a bit of a "back of the envelope" aproximation of how I think I will end up setting up the practice fixture. For first test the corner clusters with be blue, violet and royal blue while the middle is the turquoise, red and blue. The V is composed of cool white and neutral white alternating.

Of course, I haven't gotten my drivers or royal blue leds so they are missing from this mock-up.

Im running the same colors.I think youll be stoked with the results. Those LEDGroupbuy True Violets are wierd looking eh?

metalsniper · Feb 1, 2012

Yeah, I think I need to get rid of one of the cool whites and replace it with a royal blue. I switched up my pairings a little, a turquoise, a red and a royal blue on each side and then a quad of two violets and two blues in the middle. Maybe just replacing the blues with royal blues would give me the blue I want. Still haven't figured out the issue with the drivers though, half current really isn't okay with me.

I suppose I should actually update this with my progress on the demo as well if I hope to get any answers.
I got my drivers and my blues and I am waiting on my drill/tap set to get here(it was supposed to be here on the 27th), I also mounted the heat sinks to the cut aluminum. I made a casing too and mounted SPDT switches to turn on, dim and turn off the lights as well as dimming pots. As they say, a picture is worth a thousand words.

I've got the led's all soldered up and ready to go but no holes to mount them with so no photos of that yet. And of course the driver issue...

Onedesign1 · Feb 1, 2012

metalsniper said:
On that note, does it seem possible to split my power supply inlet into thirds, one for each driver and one that passes through a dimming pot to reduce it to 10V then split again to run the dimming circuits for each driver?

I need advice too as to where I need to put fuses and resisters so I can protect my leds and to measure my current.

What did you do here and do you still need advice on the fuses and resistors?

metalsniper said:
So I've moved forward but I'm having an issue, I'm only getting half of the current I should be from my buckblocks. I have a set of parallel strings in the 1400mA driver and I'm getting about 300mA across each string. any ideas?

So you're saying you have 2 parallel strings and each string is only getting 300ma as opposed to 700ma? have you checked the voltage of each string from end to end? Should be roughly 3.2 X # LEDs. Finally, have you checked the voltage going in and coming out of the dimmer pot? You should have 10V across the outside legs and the center leg should run to your dimming circuit +V. Voltage across center leg and neg leg should vary between zero and 10V via the pot.

Looking at your photo it looks like your green wire on the top pot in the photo, is shorted to the case of the pot....just an observation. Even if its nothing always be careful and strip the wires only as long as you need them. You'll be amazed how easy it is to cause a problem with sloppy soldering, etc. which reminds me...have you checked every LED for continuity to the heatsink to make sure there are no shorts?

metalsniper · Feb 2, 2012

I figured out fuses and resisters, no issues there I think.
You are correct about the two parallel strings each getting 300mA and they should be getting 700mA. The driver is getting about 19V and 17V are coming out of +Vout. The string of LEDs is running at about 16.2V. The dimming circuit is getting 10V just about (9.6V). In the second photo its not actually shorted, its because of the angle of the photo with respect to the angle of the pot, I've tried it on both circuits and its the same. Continuity has been checked and double checked as best as I can with the two battery holder I have for that purpose positive between each led and none to the heat sink. Everything is running properly except and half of maximum current.

though now that I think about it I'm not certain I wired up the pots right, I have dim+ going to the positive side of the pot and dim- going to the wiper, but nothing going to the negative side of the pot, do I need to connect that to -Vin or something or to the dim- as well? I was just going off the drawing provided in the BuckBlock literature but I am not certain what the arrow coming from dim- to the middle of the pot represents.

Onedesign1 · Feb 2, 2012

Well...I believe your 1st problem is that you have a 1000ma Luxdrive...I do not believe a 1400ma one exists and in your pic I can see 3 zeros but not the 1....if I am correct then max you will get is 500ma. Next question is how many LEDs are in each string? I counted 11 LEDs in your pic....I assume you only wired 10 of them...5 on each string? The strings have to be balanced with equal number of LEDs.

What is the voltage across a single LED?......assuming 3.2V or so?

This brings us to describing your power supply...voltage and current output...what is it?

I can't see from the picture but you say you wired dim+ and dim- ... this should be the control and Vref from the puck..control should go to the wiper and the voltage should vary 0-5v. I have not used a buckpuck but just took a peek at the literature. My other comment on wiring them was referring to my use with meanwells and using an external 10V source so ignore it. But where are you getting 9.6V from?

So after all that...max you will get is 500ma and something is limiting it to 300ma...so its either the power supply or your dimming circuit assuming you have balanced strings.

metalsniper · Feb 2, 2012

I have two different buckblocks, one is 1000mA and the other is 1400mA. The buckblock is one of luxdrives newest buck drivers and provides its own 10V dimming signal.

My circuit is not quite as pictured above. One string has 5 whites on it with forward voltages of about 3.2, the other is split in parallel, each string with one turquoise (3.0Vf), one red (2.5Vf) one blue (3.6Vf), one violet (3.6Vf) and one royal blue (3.5Vf). The two strings on the 1400mA buckblock have the same type/color of LEDs and are within 20mA.

The power supply is a laptop computer power supply providing 18.5 VDC and 6.5A, it gives more like 19VDC under the LED load.

The buckblocks are a six wire buck driver with two for +Vin, -Vin, +Vout, -Vout, Dim, Dim/Gnd. The Across Vin is where I measured 19V, across Vout is where I measured 16.8V and from dim to dim/gnd is where I measured 9.6V.

When I run the parallel strings on the 1000mA buckblock I get about 200mA instead of the 300mA I get on the 1400mA driver.

metalsniper · Feb 2, 2012

I suppose I missed a step in there that I will go back and explain. I have Dim go into the middle position of a SPDT switch then one side of the switch goes to the side of a pot, then the wiper of the pot returns to dim/gnd. The other side of the switch returns directly to dim/gnd so that when the switch is up, the light is off, when the switch is in "center/off" the led is on full, and when the switch is down it is on dimming control.

I tested the current with the switch in center/off and got the same value as when under dimming control at the max setting.

Onedesign1 · Feb 2, 2012

sorry I didn't realize the Buckblocks existed. Those do not have dual ins and outs. There's 2 Vin..+/- ... thats for your power supply only. Then 2 LED outs + and - go to your strings and you parallel off those, then 2 Dim +/- for dimming circuit. I only mention this because I am not clear on how they are wired.

I'm also still not clear on your string configuration. You mention 1 string of whites and 2 parallel strings of your colors. All have 5 LEDs. Are all 15 of these on 1 buckblock in 3 strings?

Last point is I believe you need a power supply that outputs 24v or greater based on what I saw. Page 3 figure 4 here http://www.luxdrive.com/content/A009_BuckBlock_V1.pdf shows what your current output will be based on Vin and based on your supply it looks like max case would be 1200ma output. Max voltage output at 1400ma is 75% of Vin..page 2 of link

Start by hooking just 1 string of 5 to the LED +/- and check your current. Then if reading proper (~1200ma with that supply) parallel another off that and measure again. after that you'r going to keep splitting the current as you know.