Adding Blue LED stars to my MetalHalide hood

[mongor]

Hello all,

I have a 70gal display tank and a 90 gal refugium tank (same water column) with a mix of fish and easy corals (mostly polyps)

I currently have a large light fixture that houses 2x250w MH bulbs and 2x100w blue actinic VHO bulbs.

Recently my ballast for the VHO part of the setup died and is almost $100 to replace, plus the bulbs are ready to be replaced also. The MH bulbs are new and seem to be working fine so I don't want to replace yet for fiscal reasons.

I was wondering if I could mix/match MH and LED by adding two of these 100w blue led's mounted on a heatsink cut into the top of the hood with some drivers mounted to top of the hood?

Would be a low cost replacement for the VHO ballast and would get me slowly started into the LED world.

Any suggestions/advice would be appreciated.

Thanks,

Gary

[jestep]

I wouldn't do a multi chip for this style setup. Your MH is basically what I have over my 90. I took out one of the T5's, in my case, that were in the fixture, and replaced it with a 24" blue reefbrite LED strip. http://www.reefbrite.com/reefbrite-tech-led/

 

Even with just a 24" strip the tank is glowing with the LED's only and I think it's running at about 30W. 200W of royal blue's is an insane amount of blue. I don't think I could even consider this much without seeing it in action. The other reason that I wouldn't use a multi-chip in this sort of setup, is that the spread is similar to adding another MH bulb on it where you get significantly more intensity directly under it. I much prefer a wider linear spread for the blue LED's. You will absolutely be able to bleach the crap out of unacclimated coral with 200W of royal blues and no other lights running.

 

If you want to go DIY, you can mount a longer heatsink where the VHO is and use single royal blue's every few inches with the driver mounted in the canopy.

[jedimasterben]

I would very highly suggest to stay away from eBay - especially if wanting to purchase anything Cree. Those prices are far too low for 16x XT-E, and more than likely they are counterfeit.

 

I would also suggest if you're looking for such high-output chips, use the Luxeon K 16-up instead. If the Cree in the link are counterfeit (and again they more than likely are), the K16 will have more output and use less than half the energy when ran at an amp.

 

That being said, multichip LEDs would be a very poor replacement for the distributed light from the VHOs, especially with such high output concentrated in one area instead of being spread out. If I were you, I would use a bunch of Luxeon M and a bunch of violets in strips.

 

What VHO bulbs were you using?

[mongor]

I appreciate the advice about eBay LED's. I will make sure to look for a reputable source. I am also going to look into these Luxeon K LED's also.

 

As far as the multi chip option, my assumption was that since the hood hangs over 16" from the top of the water and none of my corals are less than 18" from the surface that the light would disperse enough by then, is this an incorrect thought?

 

I am very open minded and admittedly very novice about lighting, especially LED's so I take all advice to heart.

 

thank you again,

 

Gary

 

www.marinedepot.com/UVL_24_Inch_75W_Super_Actinic_VHO_T12_Fluorescent_Bulb_VHO_Fluorescent_Light_Bulbs-UV_Lighting_Company_(UVL)-UF3245-FILTBUFLVB-vi.html

[evilc66]

Think of high power LEDs more like metal halide. It's a point source, so you have the greatest intensity directly under the light source, and the intensity drops the further off axis you go. That's very much unlike fluorescent lights where you have virtually the same intensity under the entire length of the tube. Distributing the LEDs along the length of the fixture would more closely emulate the distribution of the VHOs.

[jedimasterben]

Ok, so if you're currently using the UVL Super Actinic bulb, it has this spectral output:

 

 

 

Spectral half-width (how much spectrum it covers with at least 50% energy) is 400-440nm, peaks at 420nm, and almost all its energy is in the violet range, little in blue and elsewhere.

 

A royal blue LED:

 

Spectral half-width 440-460nm, peak at 450-455nm (the above graph is a Cree XT-E bin that I haven't seen available, most are peaking from 450-455nm). Basically nothing in the violet range, so while the royal blue will still make most of your colors fluoresce, it is not a true replacement for true or super actinic bulbs, you'd want to use a bunch of violet LEDs (with some royal blue and blue mixed in, as well) for some wicked fluorescence

[mongor]

I am starting to consider a row of LED's vs the multichips because of your recommendation and the ability to put different colors in it.

Can you recommend how many LED's you think i should put, what colors, and how many inches should I make the heatsink? I am pretty sure I can fit up to a 40" heatsink at least 2" wide. Look at the pictures I have attached to see the inside of my hood.

thanks again

[jedimasterben]

You'll want around half the wattage that you have of your VHO bulbs in total, so if you were using two 95w bulbs, you'll want around 48w of LEDs per bulb replacement.

 

For each LED strip, I'd probably use 6x royal blue, 6x blue 6x hyper violet, 6x true violet. Running at 700mA, that puts you at 54w per strip and gives you plenty of spread for each LED color. Since they're all blue and violet, you don't particularly need to cluster them as you shouldn't have color banding.

 

The 75w Inventronics 700mA driver outputs up to 108v, and each LED strip will use ~80 volts, so you would need two of those. They're expensive, but the easiest to wire up, as one side goes to the LEDS, one side goes to the wall. If you want to save a few bucks, then you could use Meanwell LDD drivers (you'd need 2x per strip, and they're ~$7.40 each) and a 48v power supply, but they're a little more effort to wire up.

[mongor]

Thanks Jedimasterben,

 

I think I will go with the Meanwell LDD drivers since I have power supplies already that will work and a fairly working knowldege of electronics. (just recently finished building my own solar panels)

 

I am assuming since you are asking for 24 LED's on each side that I will have to run 2 40" strips where the bulbs are right now, so that would be 48 LED's total and 2 40" heatsinks?

 

And I am a bit confused by the wattage math, when i searched the LED's you recommended they are 3w each times 24 LED's per strip = 72watts total? Should I go 4 LED's per color to get 48w as your original recommendation? (will affect the price quite a bit too)

 

 

This info has been great, thanx again for the advice.

[jedimasterben]

Thanks Jedimasterben,

 

I think I will go with the Meanwell LDD drivers since I have power supplies already that will work and a fairly working knowldege of electronics. (just recently finished building my own solar panels)

Sweet

 

Just make sure the power supply is ~48-54v and at least 120 watts (want to have some spare area on the power supply, the LEDs won't use all of that).

 

I am assuming since you are asking for 24 LED's on each side that I will have to run 2 40" strips where the bulbs are right now, so that would be 48 LED's total and 2 40" heatsinks?

Correct.

 

And I am a bit confused by the wattage math, when i searched the LED's you recommended they are 3w each times 24 LED's per strip = 72watts total? Should I go 4 LED's per color to get 48w as your original recommendation? (will affect the price quite a bit too)

'3w' is not how much wattage the LEDs take in, it's just a moniker for that 'class' of LED. The wattage depends on the current that you give to the LEDs. The royal blue at 700mA will use ~2w each, the blue at 700mA will use ~2.1w each, and the violet will use around 2.5w each. Only if you pushed the LEDs to 1A would they reach 3w each (and the violets would die, they can't handle over 700mA), but at that point you'd really need to consider active cooling to the heatsink (which is optional now, but it would be beneficial if it is easy for you to add).

[mongor]

Sorry for the long delay, very busy at work this week.

 

Well I got a solution that works for me and my wife, I won a LED light on eBay VERY cheap.

 

Its a Reef Brite 48" TECH LED 50/50 I got for just $92 including shipping. I know that the 50/50 is not a pure blue, but it has 12 3w Blue CREE LED's in it (as well as 12 white ones) and its very lightweight and will fit up inside my canopy. It also keeps me way under budget.

 

This will buy me some time to gather funds to still build one of the above 48" stips with the hyper violet and true violet to give the color burst.

 

Thanks again for all the help.

[farkwar]

And diffuse them.

 

 

Funny, just read the last post, you two spend a week or more helping the guy to get the best LEDS.

 

Then he goes back and buys crap on ebay.

[mongor]

Farkwar, first all the help he has been giving me is still going to be used, I am still building a light unit, I just got something temporary till I could put the funds together to do it the way he had suggested it. I put a cheap bid on a good light and didnt expect to win it. Dont belittle the help I was requesting or jedimasterben has been giving me it was not in vain.

 

Second, the unit I got was not crap, it is a name brand light with 24 Cree 3w LED's. Just to buy the LED's alone would cost me $100. It looks VERY nice on the tank right now and supplements the Metal halides perfectly.

 

http://www.reefcentral.com/forums/showthread.php?t=1992015

[evilc66]

Do me a favor. Don't call those LEDs Cree. They aren't nor ever have been Cree. Reefbrite uses Edison Edixion S LEDs. They used to have older generation Cree dies (but in a generic package), but switched to SemiLED dies years ago. It's been a pet peeve of mine for a long time.

 

Sorry for the rant

[Paleoreef103]

I'd like to add something. It looks like when you build your LED supplements they will be placed inside the fixture directly next to the MH bulbs, right? If that's the case, you're going to want some serious cooling power for those LEDs. The longevity of LEDs is very much dependent on what temperatures they are being operated at. Heat kills LEDs. They can take a decent array of temperatures fairly well, but 250 halides are HOT.

[NorthGaHillbilly]

I retro fit a panorama pro strip directly onto my mh pendant. Using an infared temp gun the heat sink on the pps reads 120 +-1 with or without the mh on. Directly under the bulb is obviously well over 200, but it dosent take far before the temp drops dramatically. With a decent fan blowing in your rig I expect temp would be fine

[mongor]

First, sorry for annoying you so much evilc66 (don't mind the rant though, its good to know) I absolutely LOVE the light though (being just a novice that is) I like it so much that most of the time I have the Metal halides off now. The room is so quite and the shimmer is so cool. I am a LED junkie now and I am really physced to make a larger unit to replace the MH's (also the wife is onboard now, so the purchase was worth it for that alone

 

When I am running the MH, I have them about 8 inches above the tank, and the LED stip is sitting on its legs directly on the tank about 4 inches behind the center of the bulbs. It is warm on top, but only a bit warmer than when im not running the MH's. There are some rather large fans on the MH fixture (too much noise though) that keeps it pretty cool.

 

On to a question about developing the new LED lights:

 

First, so I don't get slammed, this is not my design yet, I am just trying to make sure I understand the math involved for creating the panel.

 

I was considering two 'squares' of LED's one for each side of the tank. They would be 16"x14" with pretty major heatsinks. I wanted to put a total of 24 3w LED's on each square. The LED's run at 3.6v each, so if I wire 8 of them in series that would be 28.8v for each series at 700ma total correct? Am I able to run 3 series of the lights in parallel so it would stay at 28.8v but the parallel would multiply the amperage by 3 give a total of 28.8v and 2.1amps for the entire square?

 

If this is possible, would I be able to use something like this with a 30v 3amp power supply(I already have) to power the square?

 

If I am way off base, let me know, but let me know why it wont work, thats more of the education I am looking for.

 

Thank you,

 

Gary

 

p.s. what is everyones opinion on Bridgelux LED's?

[jedimasterben]

p.s. what is everyones opinion on Bridgelux LED's?

They aren't. Stay away from eBay and places like Aquastyle, they aren't worth the money for the small price difference between them and Luxeon Rebels. In a nutshell, one Rebel at 1A will replace two fake Bridgelux chips at 700mA for white, three or four for royal blue. Once we get into the Luxeon M (based on the Luxeon T diode), that difference becomes much, much larger, and you end up paying significantly more for the fake chips to make the same output.

 

Also stay away from shitty ebay/chinese drivers. Use quality components from the get-go and you will have far less issues.

[evilc66]

Just for clarity, there is a difference between Bridgelux and "Bridgelux". Bridgelux is a US manufacturer of LEDs, but they are generally multi-chip CoB (chip-on-board) style LEDs in white only. They are very good LED for high color rendering, and high output in a small area. Bridgelux also sells their LED chips to other LED manufacturers, which is where "Bridgelux" comes from.

 

"Bridgelux" LEDs are from Asian manufacturers that only use the Bridgelux chip, and nothing else. At that point, it's down to the phosphor quality and blend (for white LEDs), package quality, and overall assembly quality that defines the LED. Usually, the end output is much lower than you would see from a real Bridgelux LED. These Asian manufacturers use the word "Bridgelux" as a marketing hook.

 

Also, if the LED is not white, blue, or green, then it was not derived from Bridgelux technology, as Bridgelux only sells blue and green chips.

 

 

This is basically the same thing that Reefbrite is doing by claiming their LEDs are Cree, even though the chip is/was the only part that Cree provided.

[mongor]

Got it about the LED's, I am putting the Luxeon rebels into my search engine right away Bridgelux too confusing, not worth thinking about it

Will that current driver from amazon not work? Or is it that you dont like the no name brand?

 

Also any info on my question about running the LED in series and parallel and the voltage/amperage math?

 

Gary

[jedimasterben]

Will that current driver from amazon not work? Or is it that you dont like the no name brand?

Also stay away from shitty ebay/chinese drivers. Use quality components from the get-go and you will have far less issues.

[mongor]

ok, sorry guess I asked the question the wrong way, I am trying to learn about the process as well as what products are good.

 

The amazon driver is just a stepdown voltage/amprage driver. Is that all that is required to make an led work is a constant current/voltage that can be provided by a driver that steps down the voltage/amprage to the amount needed by the series of LED's hooked up? (I am not trying to oversimplify, but to make sure I understand)

[jedimasterben]

LEDs will work on anything that doesn't give them too much voltage or current (and at least enough voltage for them to strike). You're much better off to purchase a quality LED driver (IE Meanwell, Inventronics) than to test your luck with how long you can make one of those last.

 

Basically steer clear of anything on ebay and Amazon lol

[mongor]

ok, so now i understand the driver alittle better.

 

did my math make sense for how many volts/amps I need the driver to be?

 

"I was considering two 'squares' of LED's one for each side of the tank. They would be 16"x14" with pretty major heatsinks. I wanted to put a total of 24 3w LED's on each square. The LED's run at 3.6v each, so if I wire 8 of them in series that would be 28.8v for each series at 700ma total correct? Am I able to run 3 series of the lights in parallel so it would stay at 28.8v but the parallel would multiply the amperage by 3 give a total of 28.8v and 2.1amps for the entire square?"

[jedimasterben]

Correct, voltage determines how many you can run in series at the given amperage, driver must output at least that much voltage. I would try and avoid running parallel strings. Parallel divides the given current among the three strings, so given a 30v 2.1A driver each of three strings would run ~700mA. Any variation in voltage or temperature among the strings will cause current to vary wildly.