Outta my league DIY LED

[metalsniper]

Onedesign1, I'll give your one string at a time method a shot when I get home this evening. As it is though, I have two drivers; one 1000mA driving the white string and one 1400mA running two blue/color strings in parallel.
I hadn't even considered that I might be running the driver too high because they say they each work from 10-32V, but looking at the graphs on page 3 I suspect that that is the issue I am experiencing. Since I am only supplying about 17V and running 5 LEDs I am at the very bottom edge of the 5 LED curve, or lower, putting me at about 1A at best. Based on my numbers, probably more like 800mA.

 

[metalsniper]

Okay, this is weird. I got home today and plugged everything in exactly like it was last night and now my currents are 630mA. So, something changed but everything appears to be working as expected now. Any thoughts to why this might be?

 

[Onedesign1]

very strange indeed.

tell me this...does it seem brighter than last night? or just the reading is better? maybe error in readings last night? checking voltage across a 1-ohm resistor right?

how about the white string on the other driver?

if convinced you were reading correctly last night...check for shorts between LEDs and heatsink. Diode test on your meter...one lead on point of sale the neg lead on heatsink...if shorted the led will light up. or use 2 AA batteries of your a tester.

Though I find it hard to believe 2 drivers both flaked so its either a measurement error or that darn power supply

 

[metalsniper]

What I did was as you suggested and I first hooked up only the white string to the 1000mA driver, read the voltage across a 1ohm 1% 5W resistor, and it was at about 900mA So I hooked up one of the blues to the same 1000mA driver instead of the white and got about the same 900mA. I switched it over to the 1400mA and added the other string (so I didn't overdrive the LEDs) and got readings of about 640mA on both strings. I do feel like everything is a little brighter but as I'm sure you know its hard for the human eye to distinguish between super bright and even brighter.

When I re connected everything last night I re-did the connection between the power supply and the fixture so maybe I wasn't getting good contact there? I will proceed to do a diode test this morning.

 

[Onedesign1]

Seems you're in the right track. I guessed about 1200 ma based on your 19v power supply and those curves. The driver is using some voltage and needs some overhead to power itself. 24v supply would likely get you the whole 1400ma.

 

[jtl]

Finally started my build. I am using the pre-drilled heatsinks from Rapid Led and they came with screws which have a countersunk head. Due to the countersunk head they do not appear to touch the solder pads and ground to the heatsink but I have checked that yet. Now I wonder if I should use some small plastic washers as an insulator but I am not sure where to find them locally.

 

[metalsniper]

Not sure what your point is, I'm using high temperature nylon screws and drilling my own heat sink. If you want a question answered don't pretend you don't and you might get some help.

 

[jtl]

My point is whether anyone feels it is necessary to use plastic washers for to insulate the star. With an attitude like the one you just displayed I am surprised you get any help.

 

[Onedesign1]

The screws are used to screw the star to the from the top of the star. The bottom of the star is fact grounded to the heatsink. The top of the star is a PCB and isolated from the bottom if the star. The actual diode is on the top of said star and connected to the solder pads. The counter sink in the heatsink has nothing to do with mounting the star. Yes you need nylon washers if you're using metal screws. You can get them from ace hardware. #4 nylon washers.

Now if you're saying the screws they sent are for a counter sunk hole then theres no counter sink for it to go into and hangs up on the star then I can see what you're saying in which case I would throw them out and get proper screws for the job....and use nylon washers.

 

[metalsniper]

JTL, before you get all bent out of shape I was only saying that you didn't ask for help, you just said you "wonder if bleh" and to me that sounds like passive aggressive nothing and that if you want help come out and ask a question instead of dancing around the subject, also before you tell me off for not being nice and catering to your whims you're posting in a thread I started to answer questions about my build. If you have questions unrelated to my build then why are you posting them in my build thread? (that was a question, notice the question mark?) If you don't like my attitude, I'm sorry.

To answer what I assume is your question, and I don't mean to argue with you Onedesign1, I think you will be fine using the countersink screws because the fact that the contact point will only be the rim of the star you should be safe. However, if you would rather be safer I would agree with onedesign1 and recommend going with entirely different screws and fiber or nylon washers.

 

[KJAG]

Wow dude. Moving on... JTL, maybe PM Onedesign since he doesn't seem to have a massive chip on his shoulder and doesn't mind helping people out.

 

[metalsniper]

I don't mind helping people out and I browse all the new threads to see if I have anything to contribute, however, I don't think someone else's thread is the proper place to ask questions unrelated to the OP.
He didn't ask any questions, his post was the equivalent to talking out loud to ones self and hoping someone overhears and comes to his aid.

Your statement about Onedesign1 is true though, He has been a huge help to me through the design and fabrication of my LEDs.

 

[Onedesign1]

To answer what I assume is your question, and I don't mean to argue with you Onedesign1, I think you will be fine using the countersink screws because the fact that the contact point will only be the rim of the star you should be safe. However, if you would rather be safer I would agree with onedesign1 and recommend going with entirely different screws and fiber or nylon washers.

yeah they'll work but how shoddy would it look? I try keep it clean is all and countersink screws sticking up above a star....blehyuck...I would chuck 'em

So 'snipe ... we gots lights yet?

 

[metalsniper]

Long answer short, no. But I've got the lights all wired up and working right, and the dimming and switches are all working and I have the splash guard and heat sinks ready. I'm still waiting on my drill and tap which was supposed to get here on the 1st at latest. Supposedly tomorrow. Sad to say though that this is all still on the demo unit. I will be starting the full scale unit after that.

But it's looking great, I changed it up to use two turquoise, two red, two violet, two blue, three royal blue, two cool white and two neutral white and it is still a little white for my liking. The first photo below is both "blue" and white together and the second photo is "blue" only. They both seem to look more blue here than I remember them looking in reality though.

I think I will also be changing my main design to incorporate about double the initially planned amount of LEDs. Why, because I can and because I want to make sure I have enough to do what I want with it.