DIY LEDs - The write-up

[chris023]

:furious::furious::furious::furious:

I spent 20 minutes on this answer and it vaporized.

So will give the budget repeat.

LED drivers are categorized by wattage. You need to come up with a ball park wattage to know where in the families to look.

Watts = 3.3V x 0.8A x the total number of LEDs.

Once this is known you look at the 60, 100, 120, 150, 200, 250, 320 watt models.

The parallel isn't real hard.

Here's the basic setup:

The resistors are all the same value so you don't have to think about 'different values'.

You'll use them to shift around a few LEDs to get the strings matched current wise.

Hey, let me just say "Thanks". I really appreciate your time and effort in helping me out. I know you guys (and gals) take a lot of your time up answering many many questions, and in some cases over and over again. So just wanted to let you know that it is very appreciated.

Okay, so wattage is clear, parallel setup is clear.

Driver voltage, and calculating which resistors and fuses to use is still fuzzy.

Driver Voltage:
Based on the setup I described earlier, wouldn't each string need ~60 volts in this case (18 LEDs per string x 3.3 = 59.4? Is that correct?).
I think I read that the driver would equally distribute the required voltage to each string, so if all strings are equal, I only need to calculate required voltage for 1 string and ensure the driver can handle that single string voltage (~60 in this case), yet all strings in parallel will receive required voltage?

 

[chris023]

chris023
I have encountered the same problem as you. I wanted a long string of LEDs. After browsing the web I understood that Mean Well drivers are actually poorly designed.
I found a manufacturer of better LED drivers, here is the datasheet for their 100W model: http://www.inventronics-co.com/uploads/DS-EUC-100SxxxST 20100531 E.pdf
For your setup you will need 2 such drivers, 1 long string per driver.
I have contacted the manufacturer and I am waiting for their response.

I think i'm looking at ~250 watts for 108 LEDs at 700ma. So probably 3 of those drivers, right?

 

[kcress]

So, in taking my first "bite" of this elephant and given the math that I've seen all through this thread (thanks so much Kcress), would the following setup work...
96 XP-E RB hooked up in 8 parallel strings of 12 running on an HLG-320H-48B at 800mA
72 XP-G Whites hooked up in 6 strings of 12 running on another HLG-320H-48B at 1000mA
Please assume that I will get the fuses, resistors terminal blocks and cooling done correctly (as you can see, I believe in miracles, lol)
In looking at the data-sheet for this driver (http://www.cdiweb.com/datasheets/meanwell/HLG-320H-spec.pdf) can I assume a controller with the right 1-10V module will be able to dim these?

Precisely so! A+

 

[kcress]

Hey, let me just say "Thanks". I really appreciate your time and effort in helping me out. I know you guys (and gals) take a lot of your time up answering many many questions, and in some cases over and over again. So just wanted to let you know that it is very appreciated.

Indeed.. We do. Thanks for all of us.

Okay, so wattage is clear, parallel setup is clear.

Driver voltage, and calculating which resistors and fuses to use is still fuzzy.

Driver Voltage:
Based on the setup I described earlier, wouldn't each string need ~60 volts in this case (18 LEDs per string x 3.3 = 59.4? Is that correct?).
I think I read that the driver would equally distribute the required voltage to each string, so if all strings are equal, I only need to calculate required voltage for 1 string and ensure the driver can handle that single string voltage (~60 in this case), yet all strings in parallel will receive required voltage?

Umm.. Sort of.
For resistors just use 1 ohm, 2 or 3watt, 1%. We can get you that part number. It's all thru this thread up above.

In parallel all strings will have the same voltage across them so the current thru them will be different based on each string's total Vf. Unfortunately the Vfs of individual LEDs are ALL different. So when you make up strings they are each and every one a crapshoot. This means ultimately some strings will have a high total Vf and some will have a relatively low Vf. This means the ones with a high Vf will pass relatively less current and the low Vfs will pass relatively more current. So, you WILL have to measure all the string currents - (the reason for the resistors) - and probably move a few LEDs around your strings to get all the strings passing about the same current.

Because you will have to move a few LEDs around you don't want to glue your LEDs down OR you need to be willing to leave them glued where they are and run longer wires around to electrically re-locate them into different strings. This re-wire solution might preclude using glued LEDs on something like U-Channel because you'd likely have a few wires crossing all the U-Channel gaps - if you cared.

 

[kcress]

I think i'm looking at ~250 watts for 108 LEDs at 700ma. So probably 3 of those drivers, right?

I caution you NOT to use the drivers MosMike is recommending. They send lethal voltages across your strings.

Our LED rigs have a huge number of bare electrical exposures. Your's will have more than a thousand bare-wire sites. Each and every one of them waiting for an errant finger, hand, or forearm to kickyourass.

Every large build seems to have at least one lead shorted to the heatsinks. Do you want some huge area hooked to a dangerous voltage?

Use drivers that limit their voltages to below 50V.

 

[kcress]

chris; If you want to use 108 LEDs, I'm guessing you want about 36 XP-G whites.

That's about 3 strings of 12. This means a driver that provides a little over 40V. Call it 42 or 48V.

Run them at about 800mA times 3(strings).
That's 800mA x 3 = 2.4Amps.

48V x 2.4A = 115W so we need a driver about this power rating.



And about 72 XP-E royal blues?

Which is this same setup - twice more.

What driver? Lets look...... co.... late... ing.

Check out the HLG-120-48B "B" for dimming.
Here's the data sheet: http://www.meanwell.com/search/hlg-120/default.htm

 

[TBR701]

MSEEPMAN, have you found anyone that has the HLG-320H-48B available? I was looking for the same driver and could not find it available on line. I was not sure if it was out yet.

 

[chris023]

I caution you NOT to use the drivers MosMike is recommending. They send lethal voltages across your strings.

Our LED rigs have a huge number of bare electrical exposures. Your's will have more than a thousand bare-wire sites. Each and every one of them waiting for an errant finger, hand, or forearm to kickyourass.

Every large build seems to have at least one lead shorted to the heatsinks. Do you want some huge area hooked to a dangerous voltage?

Use drivers that limit their voltages to below 50V.

Roger that...

 

[mseepman]

MSEEPMAN, have you found anyone that has the HLG-320H-48B available? I was looking for the same driver and could not find it available on line. I was not sure if it was out yet.

I just spoke to Component Distributors and they are going to get back to me Monday to let me know availability and price. They have not stocked it before and so the factory has to get them the info. Best case scenario, someone would be waiting 2-3 weeks for them to arrive.

I'll post what I hear...though remember that I was working with the Canadian side of CDI.

 

[mseepman]

If the HLG-320H-48B is not available can someone suggest a different string setup for me that would work?

 

[chris023]

Indeed.. We do. Thanks for all of us.

Okay, so wattage is clear, parallel setup is clear.



Umm.. Sort of.
For resistors just use 1 ohm, 2 or 3watt, 1%. We can get you that part number. It's all thru this thread up above.

In parallel all strings will have the same voltage across them so the current thru them will be different based on each string's total Vf. Unfortunately the Vfs of individual LEDs are ALL different. So when you make up strings they are each and every one a crapshoot. This means ultimately some strings will have a high total Vf and some will have a relatively low Vf. This means the ones with a high Vf will pass relatively less current and the low Vfs will pass relatively more current. So, you WILL have to measure all the string currents - (the reason for the resistors) - and probably move a few LEDs around your strings to get all the strings passing about the same current.

Because you will have to move a few LEDs around you don't want to glue your LEDs down OR you need to be willing to leave them glued where they are and run longer wires around to electrically re-locate them into different strings. This re-wire solution might preclude using glued LEDs on something like U-Channel because you'd likely have a few wires crossing all the U-Channel gaps - if you cared.

Understood. Will read up more on measuring individual LED current to make the strings as close as possible. Wondering if it is better to try to measure each LED before stringing them together and capture individual numbers, then make strings based on results. Or make strings and swap out here and there... Thanks...

chris; If you want to use 108 LEDs, I'm guessing you want about 36 XP-G whites.

That's about 3 strings of 12. This means a driver that provides a little over 40V. Call it 42 or 48V.

Run them at about 800mA times 3(strings).
That's 800mA x 3 = 2.4Amps.

48V x 2.4A = 115W so we need a driver about this power rating.



And about 72 XP-E royal blues?

Which is this same setup - twice more.

What driver? Lets look...... co.... late... ing.

Check out the HLG-120-48B "B" for dimming.
Here's the data sheet: http://www.meanwell.com/search/hlg-120/default.htm

It's all making much more sense now... You are correct (at this time) on the CW & RB numbers. Thank you so much. Few final questions (for now, more will probably come up later):

1) Is 12 LEDs per string pretty much the standard? Was looking to put 18 on each u-channel 3 inches apart. May squeeze 24 per channel making 2 strings per channel, instead of trying to have a string cross channels (bumping up to a driver with appropriate wattage).

2) When adjusting the current in the driver, do I adjust to 800ma and each string will get 800ma, or do I adjust the driver to 2.4amps and each string will get 800ma? I am thinking it is the ladder, just want to make sure.

3) Any advice on fuses? Maybe something that is rated at 1amp? Are they rated on amps only, or is it volts and amps?

Once again...Thanks!

 

[mseepman]

I just spoke to Component Distributors and they are going to get back to me Monday to let me know availability and price. They have not stocked it before and so the factory has to get them the info. Best case scenario, someone would be waiting 2-3 weeks for them to arrive.

I'll post what I hear...though remember that I was working with the Canadian side of CDI.

Well, got in touch with Meanwell directly and here is what they told me about the HLG-320H

"Hello Mark,

This series is still under developing, will take another 3--6 months to release.

So sorry for the delay.

Kind regards,
Natalie Chen
Mean Well USA, Inc."

I guess I need to come up with another option for how I plan to do this.

 

[TheFishMan65]

2) When adjusting the current in the driver, do I adjust to 800ma and each string will get 800ma, or do I adjust the driver to 2.4amps and each string will get 800ma? I am thinking it is the ladder, just want to make sure.

Your right 2.4 divded by the number if string. IF they have been balanced. They will all run at the same voltage but manufacturing tolerances may allow some to be more efficient. Read this as allowing larger current flow at the same voltage. So you might get string running at 1 amp .6 amps and .8 amps or some other combination that will add to 2.4 amps.

3) Any advice on fuses? Maybe something that is rated at 1amp? Are they rated on amps only, or is it volts and amps?

They are rated as I understand in current and the rate they will blow blow. You want smoething that will blow fast.

 

[chris023]

Your right 2.4 divded by the number if string. IF they have been balanced. They will all run at the same voltage but manufacturing tolerances may allow some to be more efficient. Read this as allowing larger current flow at the same voltage. So you might get string running at 1 amp .6 amps and .8 amps or some other combination that will add to 2.4 amps.


They are rated as I understand in current and the rate they will blow blow. You want smoething that will blow fast.

Cool, thanks a lot.

 

[neltnerb]

Here's the basic setup:

I would strongly recommend connecting the two balanced chains of LEDs together at each junction. This makes it so that imbalances in forward voltage aren't propagated, giving a higher likelihood of balanced operation.

That is, if you have to use parallel chains at all. Generally it's considered poor form because the device law for diodes means that if one chain is a lower forward voltage than the other, it will get a dramatically higher percentage of the current.

 

[MosMike]

I caution you NOT to use the drivers MosMike is recommending. They send lethal voltages across your strings.

Our LED rigs have a huge number of bare electrical exposures.

Thanks for the warning! Actually I was not recommending them as I have yet to see them. But the manufacturer claims that they are UL listed... But nethertheless, with 100V in the string the usual LEDs on stars are not suitable due to leakage current in humid environment.

My personal building procedure is to:
1) check for possible shorts with a multimeter
2) seal all the bare wires with a sealant
3) fire up the fixture!

BTW is there a thread here on electrical safety of DIY LED builds? With bigger builds it should be a concern.

 

[kcress]

Well, got in touch with Meanwell directly and here is what they told me about the HLG-320H

"Hello Mark,

This series is still under developing, will take another 3--6 months to release.

So sorry for the delay.

Kind regards,
Natalie Chen
Mean Well USA, Inc."

I guess I need to come up with another option for how I plan to do this.

Well that SUCKS! :furious: :hmm3: Why are they listing it at all, if it doesn't exist.

Seems we are limited to 240 Watt or smaller units for now.

MosMike; No 'safety thread' per se, but a lot of bits throughout this thread.

 

[neltnerb]

I would strongly recommend connecting the two balanced chains of LEDs together at each junction. This makes it so that imbalances in forward voltage aren't propagated, giving a higher likelihood of balanced operation.

That is, if you have to use parallel chains at all. Generally it's considered poor form because the device law for diodes means that if one chain is a lower forward voltage than the other, it will get a dramatically higher percentage of the current.

To clarify what I mean by this, check out the attached diagram. Because each stage of LED forward voltage drop is independent, you don't end up with statistical correlations in forward voltage resulting in as large of a problem.

 

[chris023]

So here is where I am at with this design so far. I did switch it up a bit with respect to the number of LEDs. I am going with 96 total. I would love input on if you think this is a decent amount.

Not sure on the height above water line just yet. I plan on using ~60 degree optics for all. Lets just say 12" for now, my current canopy is only 6" off the water, so a new canopy would be needed regardless of what the final height decision is, so I am open to height suggestions as well. Just keep in mind that a canopy is a must in my situation. I do have quite a bit of SPS in my tank near the top of the tank. You can see a picture of my tank on page 233, post 5814 if that helps.

I am setting up to drive these in parallel series even though I do have concerns, mostly on balancing the strings Vf. Feels like this parallel or not is like a glass vs. acrylic thing... From what I am reading anyways.

I have searched and searched and have found few threads where people mention are making or made large arrays, but no real details on the drivers/parallel string aspect of things. So other than the advice I am getting here (which is greatly appreciated BTW), I feel like no one has documented their specific work with respect to this very much (pictures, etc.). Most threads out there are on smaller builds. Anyways, I did see a thread that is somewhat current where a fellow reefer is also building 96 LEDs and using 8 ELN-60-48s, there was a brief mention on parallel but nothing more. Didn't seem to be a concern to use 8 mean wells. No biggie, just thought I would mention it...

 

[spamreefnew]

I to just want to say thank you to all who helped me design my led system on here! I am still waiting for my heat sink from heatsinkusa when the thing gets here I will post some pics.

rapidled=
heatsinkusa=