DIY LED lighting?

Discussion in 'Lighting' started by Ed Seeley, 18 Nov 2008.

  1. Ed Seeley

    Ed Seeley Member

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    I need some help from the more electronically minded of you. After looking at the Maplin links quoted in another thread here I saw these LED Bright strips. I was thinking an array of these might be perfect for lighting a tank. Don't suppose anyone has used them in a DIY job in there house or something have they? If so are they independently powered or do they need some soldering and wiring? I am going to e-mail Maplins too. What I'm hoping is maybe 4 could be wired in together to one power source to replace a flourescent light.

    They may not be powerful enough to bother but allegedly each LED outputs 14kmcd (which I assume means Kilo millicandelas - or 14 candelas) and there are 30 LEDs which means 420cd. Apparently a 100W incandescent bulb puts out about 120cd so we're looking at about 3 and a half 100W incadescent light bulbs! Worth a go maybe and certainly cheaper than the ready made LED units around at the moment?
     
  2. Wilis

    Wilis Member

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    Hi Ed,
    Yes using LEDs is certainly viable as a DIY option, most will need to be behind say a perspex cover though as they have an inadequate IP rating especially the ones you are looking at from Maplin. Try looking on different sites for example http://cpc.farnell.com/ and search for led lighting strips, there are a lot out there if you're prepared to spend the time looking, as the ones on Maplin seem very expensive to me, also your local electrical wholesaler may be able to help you & will probably be a lot cheaper than Maplins also eg CEF, Network etc.
    You will need, with most applications, to purchase a separate transformer,usually 12v, to run your lights, size depends on how many lights you wish to run-basically the load the transformer can handle, you may need more than one transformer depending on which lights you choose,also some packs will come complete with a suitable transformer.
    You can also buy complete packs of ten or more round lights, usually containing 3,5 or 7 LEDs per light, that come with all necessary cables & an appropriate transformer & these usually have an adequate IP rating for this kind of application (some even being submersible)
    You shouldn't have to solder anything if you buy the right kit-the LED strips should have cables with a bare end ready to strip & put into a connector on the transformer, or male n female plugs etc.

    I've been considering LEDs myself for my 70l jewel rekord as the crappy little t8 isn't up to the job and now I've bought an aqua-medic twin halide for my new 4ft I've abandoned that diy project & need something else to stop me doing all the other things I should be doing!lol Considering using a baking tin/tray with a perspex cover-drilled out at the back as the enclosure for my luminaire! :lol:

    Hope this helps?! & let us know how you get on
    Regards
    Will
     
  3. Voo

    Voo Member

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    I've bought myself a pack of these to try make my own:
    Blue LEDS
     
  4. scottturnbull

    scottturnbull Member

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    It looks expensive. Ask maplin for a link to the datasheet for the strip, and post it here. If they don't provide a datasheet, look for an array that comes with one. Any electronics supplier worth their salt should provide one.
     
  5. SteveyG

    SteveyG Member

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    Don't waste your money on the Maplin LED strip. You'll never get a 14cd from those LEDs, and if you do, it'll be a very narrow beam angle.

    You cannot compare these LED strips from the specs they have given to another light source (like your 100W lamp for example) as a 1 candela = 1 lumen/steradian, i.e. the luminous intensity in a given direction. As the beam angle increases the luminous intensity decreases. The total output power remains the same, but they have not given this (as it would not look appealing!).

    The typical 5mm LED cannot dissipate more than about 120mW, so as you can can imagine, the light output will be a small percentage of this!

    I would look at some of the higher flux LEDs if you want some serious LED lighting. Look at Osram, Luxeon or Cree LEDs for some higher power LEDs more suited to creating an adequate light source.
     
  6. scottturnbull

    scottturnbull Member

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    There are some interesting solid state light-strips here. A few are bordering upon the amount of light output that might be useful. This one even has a driver built-in. They aren't terrifically powerful, and I would like to see a datasheet for specs on thermal characteristics, typical dc current, peak current etc., but they are relatively cheap and would definitely be strong enough to supplement existing lights, if you used enough of them. Over Christmas I might get some and see what they can do. The difficult part - for me, at least - is finding a suitable waterproof housing, with decent optical properties. I'm not exactly Mr. DIY.

    There's also some cheap 5mm LED arrays on that website. It might be worth your while trying your hand with some of those, just for experience. If you haven't worked with LEDs before, you'll undoubtedly cause a few to go into thermal breakdown. Once you can drive some cheap LEDs at their maximum, without causing thermal runaway, then you can buy some dearer ones. (I didn't mean that to sound patronising. I still burn the odd component from time to time.)
     
  7. Spider Pig

    Spider Pig Member

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    How about these ones:
    http://www.ultraleds.co.uk/water-proof- ... -1573.html

    Waterproof, supposedly high brightness- 20w equivalent for 12 quid each. 6000K near enough daylight. What else do you need to run them?

    Looking around the website they also have bulbs to use on boats. Could you put one of these into a waterproof halogen downlighter fitting for a shower?
    http://www.ultraleds.co.uk/ultra-mr16-l ... 1940.html-
    45w equivalent for 20 quid.

    Pity I don't have a spare tank to experiment on otherwise I could see my self wasting a lot of time (and money) on this :D . I assume there are other expenses and technicalities (like heat dissipation) to look at as well that might make this unattractive.
     
  8. scottturnbull

    scottturnbull Member

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    I didn't spot those before. That's cheating. There's nothing left to do. Although its closer to 3 Watts, in total, which is probably around 6 Watts equivalent, if they are driven properly.

    Those look promising from a power perspective. I suppose you could cut a hole in the tank hood, and have the vented side on the outside, for cooling, and use silicon to seal the screwed-on front-glass, from the inside, for semi-waterproofing. For a heatsink, a heavy metal washer might work, if heat was still a problem.
     
  9. Ed Seeley

    Ed Seeley Member

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    Cheers for all the inputs guys. My DIY skills are ok, until it comes to what I call fiddly electronics like this!!! Once I know what to do I can get the job done - it's just knowing what bits and peices I need! I hoped, rather optimistically, that those strips might be good enough, but after reading some it's High Output ones that I need and a fair few of them matched to a proper quality power source too.

    Please keep going with options though this is something we all need to be looking at as power prices go up; never mind saving a little bit of the planet :D !
     
  10. SteveyG

    SteveyG Member

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    The second ones won't be 45W equivalent :lol: Look a couple of lines down in the spec and it draws 3.6W including the driver. The three 1W leds are a better option in my opinion.
     
  11. Spider Pig

    Spider Pig Member

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    So how does a 1w high output bulb or the other one compare with a normal t5- i.e how many would you need to replace 20w t5? Are the equivalencies given on the website (20, 45w) advertising BS- surely you aren't allowed to be that far off if, as you say scott, the 1w is equivalent to only 6w.

    aptsys- if the 45w equivalent one only draws 3.6w, what does that mean for the power- I thought that LEDs were meant to be much more efficient than flourescent.

    Here are a couple of others on the site- but I assume that they aren't high output and so won't have sufficient intensity to get to the bottom of most tanks
    http://www.ultraleds.co.uk/metre-waterp ... -1840.html
    http://www.ultraleds.co.uk/water-proof- ... -1361.html

    Found data sheets on some other LEDs here:
    http://www.hebeiltd.com.cn/?p=led.power
    Can't say I can make head or tail of it. A quick google search revealed that most of the industry seems to be in China- no doubt there's some chinese city dedicated to LED manufacture.

    This is a bit of a diversion- but how effective would normal halogen downlighters be- like the shower ones. They certainly seem bright enough, not sure about the spectrum though.

    I really have to leave this- wasting far too much time :wideyed: - but interesting none the less
     
  12. scottturnbull

    scottturnbull Member

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    I've got a TMC Aquaray, which has 5 x 3W (or thereabouts) high output leds. The LEDs dissipate 12 Watts. It's claimed the output is equivalent to a 24 Watt T5. It doesn't stop there, though. LEDs apparently have better depth penetration. TMC say at a depth of 50 cm their LEDs produce 33% more output than a 24W T5.

    There doesn't seem to be anything special about TMC's leds. They look like most high-output LEDs of comparable power.

    Of those LEDs you posted yesterday, 5 of either would produce similar output. For the first one - the water proof ones - you'd end up with 15 emitters in total. The annoying part, is that you'd end up spending about the same as you would buying a TMC Aquaray.

    Obviously, if you already have T5s you could just buy a few to supplement the output. If you want to completely replace your T5s, you are better off buying loose high-output LEDs from Phillips or someone like that. They even sell heatsinks and optics. You'd still have to rig-up waterproofing yourself. I reckon it would probably cost about half the price of a TMC Aquaray, if you went down that route. That's probably what I'll look to do myself, longer term.
     
  13. SteveyG

    SteveyG Member

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    The latest generation of cool white LEDs that you will see in LED strips like this are approximately equal to T5 lamps at around 60 to 100 lumens per watt, so metal halides are in general still the most efficiency white light source.

    However, while the efficiency is similar for T5 and LEDs, if the light is collimated you will get more useful light into the aquarium from an LED than T5 watt for watt. But to replace 108W of T5 lights for example, you'd probably still be looking at 70W or more of LEDs...

    The 'equivalent' light output is not equivalent at all. A typical 60W incandescent lamp has a light output around 900 to 1000 lumens. So for an LED with efficiency of 70 lm/W you'd still need 14W of LEDs running at 25°C. It is also worth noting that LED brightness drops fairly rapidly with increasing temperature, and these high power LEDs require decent heatsinking to keep near their rated efficiency.

    These do look more promising though:
    http://www.ultraleds.co.uk/metre-waterp ... -1840.html
     
  14. SteveyG

    SteveyG Member

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    Their output equivalence will be based on a poor or no reflector on the T5. Whether they have better depth penetration will depend on the lenses on the LEDs. So if you are looking for the highest depth penetration you'd want a highly collimated beam from the LED, but coverage would be very patchy near to the surface.


    Having said all this, I am about to supplement my T5 lights with about 40W of LEDs with a system I am building from scratch. I have all the parts now, so I will shortly start building, and will create a thread of the progress if there is any interest? You can then learn from my mistakes :lol: I'm an electronic engineer doing a lot of optical work at work at the moment so hopefully there shouldn't be too many mistakes...
     
  15. Spider Pig

    Spider Pig Member

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    This is too addictive and I wish I knew a bit about electronics to have a go DIY at this- although I won't need it for another 2-3 years at least, by which time LEDs will have come down in price etc. i remember learning about lumens, steradians, candelas for my exams but all that went out of my head long ago.

    How about this:
    20W LED Emitter (18V~20V / 800 Lumens White) [E1202] : Electronic Gadgets, Home Gifts & Unusual Novelty Gifts - BestOfferBuy

    Demonstrated:


    I assume the more intense the source the better the penetration through the water, so if you had an adequate heat sink with these set ups then would it be a good solution? Can the heatsink be passive or do you need active ventilation like a fan?
    With the correct know how and equipment I'm sure it would be easy to knock up a waterproof version.
    Given that a lot of this stuff seems to come from China, I'm surprised that there isn't already an aquarium version available out there given how popular fishkeeping is in places like Hong Kong.

    Work to do...must ignore random flight of fancy that really don't need :mad: :D
     
  16. SteveyG

    SteveyG Member

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    We have some 150W LEDs at work, which are serious beasts and need peltier cooling, but they do lose their efficiency compared to 1/3/5W LEDs. The 20W LEDs are a bit more difficult to work with than 4 x 5W LEDs for example as the heat is concentrated in a very small area. If you could sort out the thermal design, then several of those in an aquarium would do a good job!

    The heatsinks can be passive or active, but a passive heatsink would obviously have to be several times larger to achieve the same heat dissipation. This is where T5 tubes and metal halides have the advantage - they do not have to be kept at near room temperatures to maintain a decent lifetime and light output.
     
  17. zig

    zig Member

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  18. SteveyG

    SteveyG Member

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    They're a bugger to DIY with though, unless you can get hold of the versions already mounted on an aluminium star.
     
  19. scottturnbull

    scottturnbull Member

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    You're right about the patchy surface light-spread with the TMCs. Although it looks really cool, it might play havoc with tall plants like Vallis nana.
     
  20. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

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    Hi,
    One should use caution when analyzing and comparing effectiveness of various bulb technologies. For example, while lumens are an excellent parameter to use when determining human perception of brightness it is a completely useless parameter when used in the context of plant growth. Lumens is by definition a human perception measurement not a direct light energy parameter. Plants don't photosynthesize in direct response to lumens or to watts for that matter, but instead respond to the quantum energy levels based on photon delivery rate per unit area, also known as Photon Flux Density. This can only be measured with a PAR meter which directly measures the photon flux in units of moles quanta per square meter per second, and of course, is only valid over the range 400nm-700nm. This is referred to as Photosynthetically Active Radiation (PAR).

    Lux, lumens or foot-candles are based on the perception of light by the human eye, which is maximally sensitive to light within the green region of the spectrum, at 555 nm. Our sensitivity falls off at higher and lower wavelengths and even approaches zero within the blue and red, wavelength regions which are important for photosynthesis. So while it may seem superficially that a certain light bulb is "brighter" or has better "penetration" investigation may reveal that a less exotic bulb type produces a higher energy PAR profile across the X-Y-Z dimensions of a tank.

    Likewise, watts ratings have little meaning even though we use a watts per gallon rule, which served as a useful simplified guideline when everyone used the same bulb technology. We have yet to do a proper objective comparison across bulb technologies using a PAR meter, so while there may be aesthetic appeal of whatever bulb type one chooses, one should keep in mind the above. Having said all that it should be noted that plants have amazing adaptability and will grow just as well with whatever bulb type we choose, whether a sexy LED or a humble incandescent bulb from isle 9 in Tesco.

    Cheers,
     

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