DIY LEDs - The write-up

[der_wille_zur_macht]

<a href=showthread.php?s=&postid=15266143#post15266143 target=_blank>Originally posted</a> by dtech
Soundwave said before that the blues didn't need to be at max amp since they are more for color than anything, the growth comes from the CW.

FWIW, that is in direct conflict with what other LED-experienced folks have claimed. I'm not trying to start a fight, just pointing this out. IMHO it's pretty early in the game to know details like these, since I don't think anyone has done conclusive testing. Look at the spectral plots of either of these LEDs - the shapes of the curves aren't like anything else we use in reefkeeping, even for lights that end up "looking" the same to our human eyes. To me, this says we shouldn't jump to conclusions yet!

If I remember correctly, the blues have hardly any extra output when driven at 1000mA. I went with 700 to lessen the heat generated by a 1A current.

Looking at the datasheet now, I notice some interesting things.

1) Blue holds output better than white and royal blue vs. junction temp. In other words, if your heatsink sucks, your blues will still perform OK, but your whites and royals will suffer a bit in terms of output. Going from 25 deg. C to 150 deg. C, blue loses only like 5%, while white and royal lose like 25% - 30%.

2) They only provide plots of % rated output vs. current for blue, white, and green. Blue and green have the same curve. Unfortunately, royal isn't plotted. So, at least we know that blue and white will perform the same in terms of current - in other words, you'll get the same % more light jumping from 700 to 1000mAh for both blue and white.

In the real world, I would assume you have to blend these two conclusions, since it's likely that our LEDs will get much hotter as we put more current though them. So, white and royal blue probably lose more performance at 1000mAh than blue does.

In the end, it's all probably somewhat of a wash, since so many people are using dimmable drivers. Personally, I see it as a tradeoff. All of these LEDs will give off less lumens per watt consumed at higher power (in other words, they are less efficient at higher currents), so IMHO you have two choices: 1) drive at lower currents and use a few more LEDs. This is more efficient in the long run, but more cost up front. 2) Drive at higher current and use fewer LEDs. Less up front cost but more long term energy use, and the LEDs will die sooner.

If I was making a large tank, or a deep one, I'd probably use TONS of LEDs with tight optics, driven at low currents. This would be a huge upfront cost, but more efficient over the long life I'd want out of a big tank. If I were building a nano, I'd use fewer LEDs, wider optics, and drive them a bit higher.

I'd be interested to hear if others would buy in to this same strategy?

 

[tanoman]

Hi, I am from Santaigo Chile, and I want to build a Leds lamp.
My reef is 183cm long x 60cm High x 50cm wide. Plus a sump.

I have 700lt with the tank and the sump.
I use at the moment 3 HQI 150w 14K + 3 PL actinics 55w 10k + 3 PL white 55w 10k. Total 780w

I have SPS, LPS corals plus fish, shrimps and clams.

I dont know how many leds to use, the order that they have to go, colors of leds and names of it to buy them or see if i can find them here. Or try to buy them oversea.

Can someone help me and give me an order of leds colors, to have a 250w par?

I saw that tyhe solaris lamp has leds and give 400w of par. Do you know where i can find those leds?

Thanks

Sebastian

 

[james3370]

<a href=showthread.php?s=&postid=15266888#post15266888 target=_blank>Originally posted</a> by der_wille_zur_macht

^^^ + plus what somebody advised me over on nanoreef.....most people running at 1000ma are dimming them down, but why not start at the upper end & dim down than in the middle???? you may or may not need the extra brightness of 1000 vs 700 & as long as your LEDs can handle & power supply can provide, why not start at the top & come down???

 

[james3370]

<a href=showthread.php?s=&postid=15266904#post15266904 target=_blank>Originally posted</a> by tanoman

".....reefcentral's vb code will automatically change any links there to reefcentral



Yeah there is a reason some words are on the filter, generally it is because they are not welcome here. Going out of your way to circumvent the restrictions is not appreciated.

 

[kcress]

der_wille_zur_macht; I think you summed that up nicely.

james3370; I think you did too. And I can't argue with the dimming down concept.

tanoman; You'll just have to look thru this thread and make your best estimates. I suspect no one wants to try to guess what would be best for your particular setup.

You could mimic soundwave's setup which is right at the front of the first half of this entire thread. He thoughtfully provided the entire shopping list, as have a few others.

 

[dtech]

The added input is great, I may be wrong in my saying that, it was from memory, my bad if I misquoted, no one elses. I am going to do the dimm down if I need to, I mainly want the dimmers to acclimate things to the light and also maybe add a dimm to a controller. I am doing 30 cw, 30 rb. but doing everything else pretty much as soundwaves setup, same height etc. I may add 60deg optics in the future if I'm not happy but I think I will be judgeing from what I have seen. One of the local guys here is a commercial lighting guy and he explained that the meter readdings we are used to may be all hokey in the world of led's, due to the light can be axact solor not blends of others to get that color. I did alot of readding on that after doing some net searches forled's and how they work etc. Medical lighting is going tis way as they can accuratly control light color which in surgery can be huge, makes sense to me, again stuff I jhave read. also the medical stuff they praise the lower temps that docs have to stand under for long periods of time. Just another tid bit.

 

[sphil876p]

Hey, I posted this question a couple of pages back and wanted to see if any of the electrical engineer types could offer any feedback........ Thanks

<a href=showthread.php?s=&postid=15239235#post15239235 target=_blank>Originally posted</a> by sphil876p
Hello, I have a quick question regarding the Meanwell drivers. I have one of the ELN-60-48D powering a string of 15 Cree XRE leds. It has internal adjustments that set to their max output drives the string 53.5 V at an overall current of 800MA. I have tested this over a period of several hours, and the driver does not appear to overheat. Everywhere I have read suggests 13 leds per string. Will running the strings this way cause damage to the drivers?

 

[hlem]

what's wrong with extreme deal? thought i saw them there for less than 5$

 

[sphil876p]

I purchased by first batch of whites from deal extreme. I received 18 pcs within 2 weeks. I have ordered 35 more and expect to see them by the end of this coming week. I has taken them longer to fill my 35 piece order though about 3 weeks total. I can not seem to locate the royal blues on their site though.

 

[kcress]

sphil876p; Pushing the envelope huh.. Always risky. But! That said, if you keep the case temperature reasonable you should be okay.

I can also say the next unit you pull out of the box may not 'over adjust' that much and so may not work in the same situation.

One other point is that your LEDs, once boxed up, and running in their final position may run hotter and have a higher VF which would mean they need more than 53.5V. If that happens then your system will go out of regulation and you will get whatever current you get and it will change with temperature and with your house voltage. Not a good place if it happens.

 

[sphil876p]

Thanks for the response kcress. I will be pulling fresh air into the fixture right past both of drivers for this array. The fan will blow onto the sink and out of the fixture at the base of the sink fins. I wired up the second driver last evening, and it actually is pushing 54.8V :eek2: . I wired it to the same string and it is also running at 800MA. If I run the string without the fan blowing on the heatsink the current seems to creep up over time, actually close to 1000MA. Is this the situation that you are describing as being out of regulation? I have wired a 1A glass fuse in line with the positive line to the LED string. Will this be sufficient protection to safeguard against the regulation problem?

 

[bigbus]

Great thread and great input about led's. I have decided to diy a led fixture for my 110 if it doesn't break the bank. Do you guys think 36 CW and 36 RB would do the job? Thats about my limit for the project. Cutting it with even less led's would be great. The tank is 60" wide and 18" tall. I'm thinking a 12" by 8.5" heatsink with 24 led's each on them and placing them in the middle 36" of the tank? I don't think i'll have corals towards the edge of the tank or even rock for that matter so these unfilled 12" on each end won't be a big deal.

Any suggestions on reducing the number of led's would be great!

 

[kcress]

<a href=showthread.php?s=&postid=15269208#post15269208 target=_blank>Originally posted</a> by sphil876p
Thanks for the response kcress. I will be pulling fresh air into the fixture right past both of drivers for this array. The fan will blow onto the sink and out of the fixture at the base of the sink fins. I wired up the second driver last evening, and it actually is pushing 54.8V :eek2: . I wired it to the same string and it is also running at 800MA. If I run the string without the fan blowing on the heatsink the current seems to creep up over time, actually close to 1000MA. Is this the situation that you are describing as being out of regulation? I have wired a 1A glass fuse in line with the positive line to the LED string. Will this be sufficient protection to safeguard against the regulation problem?

Yep! You are over the edge.. PULL UP! PULL UP!! :hmm5:

I actually had it backwards but I just looked it up. The forward voltage actually drops as an HBLED gets hotter. (Called a negative temp co in EE lingo.) This would lead to greater and greater current in the case of an unregulated power source.

A proper current source running in it's design range would, of course, compensate to keep constant current. This is one of the major points of a current controller. Otherwise as a bank of LEDs gets hotter it draws more. Then it gets hotter... Then it draws more.. You see where this is heading right? Poof.

SO! Because your driver is not regulating means you have left its SOA (Safe Operating Area). You need to pull one or two LEDs out of its string. You have my condolences.

 

[khanb31]

<a href=showthread.php?s=&postid=15265174#post15265174 target=_blank>Originally posted</a> by james3370
personally, i would run them at the max they will run (RB @ 1000ma & CW @ 700ma) & use dimmable buckpucks. that way you can fine-tine them to the color & brightness you like w/ the pot

so how many of each LED do you have?? do you have power supplies yet?? post some details & i'll give ya my

Well James, Thus far I only have the LED's. I left myself open to different possibilities because I want to make this as cheap as possible but still meet my goals.

Since im on the topic of cheap, Here is what I got my LED's for.

1) Cool white Cree XP-E LED
Code- XPEWHT-L1-0000-00C03 (WF, Q4)
Price- $3.20 reflow mounted to ¾ inch star add $1.40

Qty- 24
Subtotal= $110.40


2) Royal Blue Cree XR-E LED
Code- XREROY-L1-0000-00A01 (Q4)
Price- $3.98 each reflow mounted to ¾ inch star add $1.40

Qty- 24
Subtotal= $129.12

TOTAL= $239.52 + shipping

Pretty cheap! Not to mention I got them in two days after I ordered them! WOOT!

So, as far as Drivers and power supplies....I am pretty much set on dimmables. I dont really mind right now if I can dim them, but I want the drivers to have the feature. Reason being is I want to get a profilux plus 2 controller when I have the chance. This will allow me to really create some cool lighting effects.

Now the interesting part about how Im doing my setup is I will be moving the LED's across my new 6 foot tank in a pendant style configuration. I will have 12 LED's (6 roy blue and 6 cool white) sit stationary across the length of the tank but that will mainly help me control sunrise/sunset as well as for viewing pleasure.

I will definitely have an EXTREMELY unique optics combo when I design the reflector. I have done a good amount of research thus far on it and I have a good idea of what im going to do. Ill post it when im further along.


SOO, now back to drivers.

If I had a driver with an output of 700mA, could I put a blue and a white on the same string? OR, do I have to ALWAYS put whites and blues on separate drivers?

 

[dtech]

You can run wh and blue on the same string, but whatever you are driving that string at is what they all will be at.

 

[khanb31]

ah ha......then I will decide very shortly what I will be getting....

thanks for the help!

 

[james3370]

<a href=showthread.php?s=&postid=15270486#post15270486 target=_blank>Originally posted</a> by dtech
You can run wh and blue on the same string, but whatever you are driving that string at is what they all will be at.

exactly....the only thing that changes is the forward voltage (which for cree is typically 3.7 @ 1000ma & 3.3 @ 700ma)

 

[AndyReef]

I am planning on using the RKE ALC to control my LED array. Does anyone know anything about using the 0-10V for dimming? What LED driver would work with the 0-10?

 

[JoshuaG]

<a href=showthread.php?s=&postid=15271988#post15271988 target=_blank>Originally posted</a> by AndyReef
I am planning on using the RKE ALC to control my LED array. Does anyone know anything about using the 0-10V for dimming? What LED driver would work with the 0-10?

The Meanwell ELN-60-48D drivers have dimming wires that will hook right up to the ALC.

 

[AndyReef]

If I use the meanwell how many of the CREE XR-Es could I run on one driver? Would I need to add any resistors to the circuit? Also, does it just connent to 120V AC?