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abhishekls
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 Posted: Tue Aug 21, 2012 1:23 am Post subject: How many LEDs for a 39W T5HO |
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How many LEDs will I need to replace my current 4 X 39 watt T5HO lights.
Also which LEDs are advisable to buy ?
Lastly, are LEDs good for planted tanks, or they are hit n miss with respect to spectrum ? |
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Nidhi
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| Posted: Tue Aug 21, 2012 9:45 am Post subject: Re: How many LEDs for a 39W T5HO |
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Abhi,
How many LEDs will I need to replace my current 4 X 39 watt T5HO lights.
you cant compare LED with Other lights, if your tank is 36x18x18 then 12 nos or if 48x18x18 then 16 nos of cool day light cree LED will do.. each will consume around 5W of power when driven to the max of the specified current.
Also which LEDs are advisable to buy ?
These are the ones sold on Rapid led for planted tanks.. in DIY KITS.
1.CREE XP-G R5 5W Cool White LED
2.Philips Rebel ES Cool White LED
Lastly, are LEDs good for planted tanks, or they are hit n miss with respect to spectrum ?
They are working I hope, since most of them are referring to Rapid led..
They are of cool day light color. equable to 865 of Tubes..
Or if wanna go for Chinese LED, then 1W LED x 70-75 nos for 3 feeter and 90-100 if 4 feeter.
If going for 3W LED, then 35-40 of these on 3 feeter and around 50 for 4 feeter..
Since even I wanted to do a DIY on this , I calculated after going through many articles on line.. and ended up on this..
I would like to hear more from others.. |
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josyjames
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| Posted: Tue Aug 21, 2012 11:42 am Post subject: Re: How many LEDs for a 39W T5HO |
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| Nidhi wrote (View Post):
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if your tank is 36x18x18 then 12 nos or if 48x18x18 then 16 nos of cool day light cree LED will do..
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@ Nidhi, I should say that 12 nos of Cree would not be sufficient for a 36x18x18 tank. On what basis had you reached to the conclusion of having 12 nos for a 35x18x18 tank?
I would say that you need more for the above tank dimension. Also you need to choose the right optics depending upon the tank dimension. You could still do away with 12 nos. If you have chosen proper optics, you can cover the entire surface area of a 36x18x18 tank. But you would have less intensity when using less number of led's. The PAR value would be on lesser side when using less number of led's to cover a larger surface area.
@ abhishekls,
You cannot compare the number of led's equivalent to any other lights. When it comes to led's, generally the number of led's are chosen based on the tank surface area and tank depth. I use 9 led's for a 12" cube surface area. So based on the surface area of your tank, you need to calculate the number of led's required. 9 led's for 12" cube - The number of led's would reduce if you are choosing Cree. As Cree led's have higher lumens output while comparing to other led's.
Hence higher the lumens output, lesser the number of led's to be used in a setup. |
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Nidhi
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| Posted: Tue Aug 21, 2012 12:03 pm Post subject: Re: How many LEDs for a 39W T5HO |
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@ shellly,
Cree or the Phillips can be driven at approximately 5 times the Regular 1W LED, means that each will be delivering around close to 460 lumens at 5W.. so 12 X 460 = 5520 Lumens..
which comes to around the same as my present 45X2 HO CFL..
And, yes optics must be used.. depending upon the height of the mount..
But as I said, It's just my theoretical calculation.. |
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abhishekls
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| Posted: Tue Aug 21, 2012 12:15 pm Post subject: Re: How many LEDs for a 39W T5HO |
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Thank you for the information guys
@shelly
As per your calculations, I would need around 42 Leds to cover my tank.
If I use it should come down to 36 ?
However, I noticed you did not mention if it was a 3w LED or 1 W LED
if I use 3W will it significantly come down
@Nidhi
I think as per my reading too your Lumen calculations seem to be correct.
But I had a question and that is, how high should the LEDs be hung to cover the entire surface area.
Also, I am not able to get the correct kelvin ratings also of Cree LEDs or the ones available here.
Any idea which ones would be closer to 6.5k-8k range ? |
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Nidhi
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| Posted: Tue Aug 21, 2012 12:36 pm Post subject: Re: How many LEDs for a 39W T5HO |
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Abhishek,
The Cree I have mentioned is around 5000 to 8300 K and the Phillips says 4500-10000K color temperature (5650K typical) , they never give the exact kelvin.. as most manufacturers.
They generally term it as Warm day light, neutral white, cool day light etc.. we need to buy the cool day light..
The height seems to depend on the optics we use like 40, 60 or 80 degrees.. with 40 deg you can fit it higher and 80 means a bit closer, may be like 6 inches from the water level.
If you don't go for the optics then you will loose some of the precious lumens..
Where as the Chinese make LED will be having a term like ultra cool day light.. and may be like 6-8K rating. |
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josyjames
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| Posted: Tue Aug 21, 2012 1:01 pm Post subject: Re: How many LEDs for a 39W T5HO |
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@ Abhishek,
The height at which you want to keep the hood entirely depends on the optics used. Nidhi had already mentioned it.
In the above hood, I have not used any optics. The viewing angle of the led is 140 Deg. Since I have not used any optics, you can notice that the lights are actually falling outside the tank. So if you don't use optics, you would be wasting the light.
So better choose the optics depending upon the hood that you are going to make. If you are planning to have the hood which is sitting on top of the tank, say the hood would be sitting 4-5" above the water surface, choose wider optics.
And if you are planning to hang the hood from the top, then choose the lower optics. You can even hang the hood from the ceiling of the room if you have the right optics.
The above hood is sitting on top of the tank. Hence I have chosen 60 deg optics.
This hood is hanged from the ceiling and the optics chosen is 45 deg. |
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josyjames
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| Posted: Tue Aug 21, 2012 1:05 pm Post subject: Re: How many LEDs for a 39W T5HO |
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| I use only 3-5 Watts LED's since with higher wattage led's the options for optics is very very less. So if no optics, you have lesser control on light penetration to cover the surface area of the tank. |
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abhishekls
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| Posted: Tue Aug 21, 2012 2:24 pm Post subject: Re: How many LEDs for a 39W T5HO |
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This is real good information @shelly and @Nidhi
I will try to get the raw materials and update about the progress. |
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