# LED lighting   high vs low wattage LED's



## Antipofish (26 Feb 2012)

Just a thought... and its a question I should have asked the guys I was with yesterday but didn't think to !

A lot of the top end / expensive units seem to be higher wattage and fewer bulbs... the likes of Arcadia, TMC grobeam, Ecotech Radion, and even some of the homemade ones that reefers are getting into.  These typically have no more than 30 LED's per unit.  But you also see some that have literally hundreds, though the bulbs are often as low as 0.06w as opposed to say 3w on the aforementioned units.  

I am just wondering why the difference ?  Im probably answering my own question here, as I assume the higher the wattage then the greater the light penetration, but it begs the question "why bother with a unit that has hundreds of LED's" ?  

If anyone can shed any light or point me to any useful articles on the subject I would be grateful.

Cheers


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## ian_m (29 Feb 2012)

Basically with high power LED's the light is more directional, thus will penetrate further into the tank and you will get more lumens/Watt compared to using many smaller LEDs.

However the downside with high power LED's is they are not cheap and great care has to be taken in getting rid of excess heat, which is why some LED luminaires have fans fitted.

The heat issue is the major reason why LED lights have such a poor reputation in lighting fixtures. For instance CREE quote 60,000hours lifetime @ 50°C but only 1000hours (40 days !!!) and 110°C   (a rough rule of thumb is halving of lifetime for each 10°C rise in temperature).


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## Radik (29 Feb 2012)

It is about efficiency Watt VS Luminosity. CREE led are one of the top efficient LED around where 1W give around +-120 lumens depends on type of LED some more some less. You can't compare that cheapest low watt led they stand no chance.

Yes some people run them to the hill then lifetime is poor my DIY fixtures never go over 30°- 40°C. Also choice of heatsink is usually poor with low surface area for heat dissipation.
I do not know where poor reputation comes from I never heard anything about complaining. But when people are idiots and do not know what they are doing no wonders can be made.

I think TMC's are also running around 35°C.


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## Antipofish (29 Feb 2012)

Cheers for the info guys.  Id love to try and make my own rig but it does seem an expensive task.  Id love to make a rig that had mainly cree LED's but then a few different colour ones, all with the ability to adjust intensity therefore allowing complete control over colour temperature.  Is this possibly ?  The Ecotech Radion unit does this, but at a price I cannot possibly afford at the moment.


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## Radik (29 Feb 2012)

ok without skill is electronics you will not be able to do it . Best you can do is to buy large TMC controller for 8 channels. Each channel can power up 5x cree. Then use this TMC controler to power up your DIY fixture. but this controller is 180 GBP.

Or buy small controller for 65 to power up 2x5 LED


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## ian_m (29 Feb 2012)

Search for "LED drivers UK" will find you some 1000mA LED drivers suitable for driving CREE (or equivalent) LED for under £10.

RS at rswww.com will sell you how power LEDs.

Just need to mount on suitable heatsink and make waterproof, which is not easy


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## Radik (29 Feb 2012)

those you suggest are not dimmable and he was asking on intensity control so no it is not that easy as just buy driver under tenner. Then he needs 1-10V dimming switch which is over 10 and that's just for one group of LED and manual dimming so he will be better buying ready product


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## Mungoo (19 Mar 2012)

Can 12v LED lights be directly connected to a leisure battery?
I am looking at some 12v LED lights, that use 5amps, i want to use them in my camper van which has a 12v 110amp leisure battery. Can these lights be connected directly to the leisure Led Light Accessories Connector / Power Wire LED Controllers battery without burning them out? Do the LED lights only draw however many amps they need?


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## foxfish (19 Mar 2012)

So what would be the issues or problems with building a DIY suspended hood fitted with a number of G10 LED fittings like thesse http://www.energybulbs.co.uk/products/L ... GU10+Bulbs
There is even a dimmable version with a built in mini fan!
Seems to me you can walk into B&Q & buy all the components to build a dimmable & powerful unit?


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## ian_m (19 Mar 2012)

These bulbs are nice, but require a cooling airflow, this is what the holes around the lens at the front is for, to allow air to convect through and come out the back. If used in a roof space, as downlighters, there are severe restrictions in usage of insulation (which should be present in a roof of course) and keeping it away from these lights for both thermal and dust reasons.

We played with one of these at work and I would disagree with the 50W equivalent, I would say only equivalent to 35W halogen (or even 20W   ).

Might be of use in an aquarium, but I suspect you will have problems cooling these lights. I suppose you could place them behind a sheet of glass, to keep the damp/water out and have a fan for drawing air out from a chamber behind these lights, thus cooling them, might be a way forward. Wonder what the glass would do to the light power though ?

Just investigated further, made all the more difficult to compare as a 50W halogen quotes light output of 2000 candela but the Philips 50W LED equivalent quotes 270 lumen. However one is total light and other is light over solid angle and may be converted by 3.44 cd/lm for 35 degree light (Google it or calculate via 4 x pi x [sin(angle/4)]^2).

Thus 2000 candela is 2000/3.44 = 580 lumens. Thus LED @ 270 lumens is ony half as bright.


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## OllieNZ (19 Mar 2012)

The GU10 bulbs seem to work well




My rig, cost me about £13 incl bulbs (single 3w LED). Although I'm looking at getting something like this as it is a bit prettier and will give me a 3rd bulb http://www.diy.com/nav/decor/lighti...Spotlight-Satin-Silver-Painted-Effect-9381147

After Rescape


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## rolexbene (29 Mar 2012)

Maybe not exactly what you were looking for in terms of control but here are some cheap parts that might work for you for between 5-8 3W leds.
http://www.ebay.co.uk/itm/320874621395? ... 1479wt_876
http://www.ebay.co.uk/itm/170700515382? ... _520wt_876
http://www.ebay.co.uk/itm/New-Cree-XR-E ... 33729c75b9

If anyone has any comments on why this would not be a successful collection of working parts please let me know, cheers.


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## Sentral (5 Apr 2012)

As already been said; you can make your own LED rig for not much money. Radik helped me out when I initially built one last year. 

I've just purchased a couple of these for a new setup though http://www.ebay.com/itm/ws/eBayISAPI.dl ... 0356170265 
You just need a 12v power supply  easy


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