LED Lightning

Discussion in 'Equipment' started by denzil, Sep 10, 2012.

  1. sfsuphysics

    sfsuphysics Supporting Member

    Fans are nice because they allow you to get density of LEDs, which can be useful if you want to minimize color banding.
  2. FeliciaLynn

    FeliciaLynn Supporting Member

    I just went with the cheaper un-drilled heatsinks and used epoxy to attach the LEDs. The LEDs seem really well attached that way, so I'm not sure that drilling is really necessary unless you plan on knocking your fixture around a lot or something else that might detach the LEDs.

    As for color temperature, I went with a blend of warm and cool whites. What I have is:
    4500k - Neutral white
    10000k - Cool white
  3. denzil

    denzil Webmaster

    Yeah, I'm not entirely sure yet which Kelvin is appropriate for different types of corals.
  4. CCT/Kelvin ratings is based on human perception and is subject to differences in binning as a result of the manufacturing process. Zooxanthellae care about spectral density in the absorption region.

    For example, take a look at the spectral power distribution on Cree's datasheets:

    XPG Page 3

    XPE Page 6

    A "basic" fixture that mixes blue and white will grow most corals, based on anecdotal evidence. The ratio of blue to white, as well as the spectral output of each, are more of a matter of human aesthetics, as is mixing in other colors, as long as you cover the absorption spectrum of chlorophyll a and c. Focusing on the spectral output increases the efficacy of a LED fixture. Just my 2 cents.
  5. sfsuphysics

    sfsuphysics Supporting Member

    Was wandering around RC and saw this


    Immediately came to mind how beefy is this guys house wiring.
  6. Vincerama2

    Vincerama2 Evil Overlord

    Felicia, nice meeting you at the swap! Thanks for the lead on the DIY LED kits too.

    I have LOTS invested in MH. I even have an unused dual 150 W fixture and an unused 175 MH SE ballast. But I think I'll go LED anyway, on my 180.

    The power savings and MOSTLY the replacement bulb (!!) costs make LEDs way more attractive nowadays.

    Felicia, you said you epoxied the LED's to the heatsink?! Is the epoxy thermally conductive? I know with CPUs you need thermal paste to transfer heat from the CPU to it's heatsink, I would think the epoxy would insulate the LED from the heatsink ... or is that not how they work? I"m an LED newbie here.

    Time to start selling my RBTAs for LED money...

  7. FeliciaLynn

    FeliciaLynn Supporting Member

    It was nice to meet you as well!

    You'll love not having to deal with the bulbs and your electric bill when you switch to LEDs! The epoxy that came with the kit I used is thermally conductive heatsink epoxy. It was included in the kit from Aquastyleonline.com which ships from Hong Kong, so the epoxy tube is written in Chinese, so I couldn't tell you for sure what brand/kind it is. If you buy the epoxy separate, just look for "heatsink epoxy" or "thermal epoxy".
  8. denzil

    denzil Webmaster

    If you do end up getting separate epoxy, Arctic Silver 5 would be ideal (from the computing world).
  9. denzil

    denzil Webmaster

    The more research I do, the more I'm convinced that Cree's are what I should be getting. However, if I add everything up, it's close to what I would pay for a Kessil A350W. I'm looking at ~$240 for 48 Cree LED's or ~$180 for 36 Cree LED's, ~$60 for a 24" x 8.46" aluminum heatsink or $46 for two 15.8" x 7.1" aluminum heatsinks, $82 for two Meanwell LPF-60D-48's, and misc. wires, etc. At minimum I'm looking at $300 in any permutation of options.

    I don't know, it might just make sense to get the Kessil A350W...
  10. FeliciaLynn

    FeliciaLynn Supporting Member

    The Bridgelux LEDs that I used in my fixture are quite a bit cheaper than the Crees, but there has been a lot of debate about whether they are as good as the Crees. Honestly I think that Crees have just kind of become the brand name of LEDs and so everyone assumes they are the best. Just to show how great my Bridgelux LEDs are, here are some growth photos of SPS corals in my tank.

    1) Bali Green Slimer and Sour Apple Birdsnest
    The day I got the frags: 2/2/12

    The same frags on 9/11/12

    2) ATL Red Polyp Undata
    The frag in the store on the day I bought it: 3/1/12

    The same frag on 9/11/12
  11. denzil

    denzil Webmaster

    Felicia, those are some awesome results. I think I'm pretty set now on getting the AquaStyle kit. I inquired with AquaStyle and they recommended the 36 LED kit but I think I may go with either those or the 48 LED kit. Whether I get the 36 or 48, I plan on getting the LED's split three ways: royal blue, 6,500K, 10,000K. They'll be spread across two of their 15.8" x 7.1" aluminum heatsinks.
  12. sfsuphysics

    sfsuphysics Supporting Member

    Be careful 2 of those meanwell drivers won't handle 36 LEDs, with a ~3.3V forward voltage you need at least 3 drivers to handle 36
  13. FeliciaLynn

    FeliciaLynn Supporting Member

    Sounds like a good plan Denzil! The guy that runs Aquastyleonline is super helpful, so I'm glad you called him. I think either the 36 or 48 LED kit will be fine on your tank, and the heatsink plan sounds good. I like the blend of LED colors you picked as well. If you end up getting that kit, let me know if you have any questions. :)

    Also, the 2 drivers Aquastyle provides with the kit are rated to run that number of LEDs. They're not Meanwell driver (I forget what brand they are), but they work just fine.
  14. denzil

    denzil Webmaster

    I'm getting the Meanwell LPF-60D-48's which are rated at 60W each and should be enough for 36 LED's. I'm definitely not getting the Maxwellen dimmable drivers because eventually at some point I want to utilize the PWM via a controller (that I'm working on building) to ramp up/down the lighting.

    I'll probably end up going with the 48 LED kit so I'll end up getting three Meanwell LPF-60D-48's to drive the 48 LED's.

    Yeah, that's some good customer service. :)

    I'll definitely let you know if I have any more questions.
  15. sfsuphysics

    sfsuphysics Supporting Member

    Unless you run two strings in parallel at half the power, you won't have enough voltage to handle 18 LEDs on one driver. That driver has a max voltage of 48V, assuming a 3.3V forward voltage across each LED you can put 14 on one driver.
  16. magnetar68

    magnetar68 Guest

    One thing that I ran into with the Meanwell was the dimming caused blinking. The issue is that forward voltage of the LEDs is a function of current. So at the lower currents provided by the driver when dimmed the total forward voltage of the string is lower. If the total forward voltage goes below spec for the driver it it programmed to blink the lights. I had to add an extra LED to the string so that at the lowest dimming setting there was no blinking.

    The point is that you need to look at both the low end and high end forward voltage when planning on using the dimmer functions. I do not know if this is different for the PWM version as I had the 0-10V version.
  17. denzil

    denzil Webmaster

    Hrm, it's weird that the LED's I want to go with have 3.7V forward voltages so really I'll probably need more dimmable drivers. Assuming 3.7V, I really can only string up 12 LED's in series. I totally overlooked the forward voltage, despite the fact that you mentioned it, haha. So you're right Mike, it's either three drivers for 36 LED's or four drivers for 48 LED's.

    I wonder why the 48 LED kit is sold the way it is, knowing that at max power they're only at half capacity with the LPF-60D-48's.

    After some thought, I think I might just stick with the basic 36 LED kit with the two 15.8" x 7.1" heatsinks. That'll only put me out $145 and keep me moving along in the tank build.
  18. FeliciaLynn

    FeliciaLynn Supporting Member

    You seriously can't beat $145 for a nice LED fixture. Sounds like a good choice. My 36 LEDs are more than enough for my 30 gallon, so I'm sure that will be enough for your tank.
  19. denzil

    denzil Webmaster

    Yeah, I think so too. I'm finally moving on to the next phase... planning/building the stand. :)

Share This Page