# How many Cree XPEs for 55G?



## Tanan (Mar 11, 2009)

Hey everyone.
So I was using those cheap chinese 4x10W LED chips and 2x10w floodlights over my 55G (48"x15x18). Since they werent enough so I combined 3x36W Osram 8000K PLLs. Now in 3 months I will need to change those PLs and since the chinese 4x10W LEDs have done miserably. I am going to replace them with 20 Cree XPE-R3 cold white leds each run at 900mA. I need these to cover around 30"x15" area and should atleast be able to get me a decent carpet of glosso. The 10W floodlights have done great and combined can take care of the 10x10 area. Do you guys think 20 leds will be enough? Or should I get more or add some red and blue to the mix? Lights will sit around 2-3" above the water surface. 
These are the LEDs.
http://www.aliexpress.com/item/10PCS-ORIGINAL-CREE-Xlamp-XPE-XP-E-R3-1W-3W-High-Power-LED-Emitter-Bulb-with/1245787152.html?PID=6147090&src=ale&URL=http%3A%2F%2Fwww.aliexpress.com%2Fitem%2F10PCS-ORIGINAL-CREE-Xlamp-XPE-XP-E-R3-1W-3W-High-Power-LED-Emitter-Bulb-with%2F1245787152.html&cv=11032041&cn=null&tp1=c5zxfg87skkh&tracelog=null&af=cj_6147090&vd=30
Drivers.
http://www.aliexpress.com/item/Free-shipping-high-quality-30W-900mA-LED-driver-power-supply-LED-floodlight-driver-10-series-3/1198019731.html?PID=6147090&src=ale&URL=http%3A%2F%2Fwww.aliexpress.com%2Fitem%2FFree-shipping-high-quality-30W-900mA-LED-driver-power-supply-LED-floodlight-driver-10-series-3%2F1198019731.html&cv=11032041&cn=null&tp1=eogrgdgvw3b7&tracelog=null&af=cj_6147090&vd=30


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## TropTrea (Jan 10, 2014)

The XP-E R-3 is a 5,300K chip Which will run at roughly 2.6 Watts each at 900 ma. Also keep in mind that the XP-E is an old series of chips and has been replaced by the XP-G series now in current production. The XP-G's would give you roughly 13% more light per watt than the XP-E's and you run them up to 1,500ma so each chip could give you up to twice the amount of light.

Most of my builds of LED's were for salt water tanks with a goal of 200 PAR at the substrate. On that bases I would say your 20 Chips would be enough for an area 18" squared with the LED's roughly 18" from the substrate. That is an area of 338 square inches. Since you lighting an area of 450 square inches my guess is your PAR at the substrate would be around 150 Par. This should be more than enough and you may want to even have your lights higher than 18".

As far as spectrum is concerned I'm not an expert on LED's in a planted tank. I do know some plants like a little more red red light and others need a little more blue light. These LED's should produce enough blue light for your needs however there might be a shortage of red light. Simply adding red LED's to the mix can be way over kill. 

I personalty would run a combination of the R-3's at 5,300K with a few R-2's that are 3.200K to boast the red end of the spectrum slightly. Aiming for a PAR around 100 I would run 10 R-3's and 4 R-2's.


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## Tanan (Mar 11, 2009)

Thanks Troptea. I was thinking of getting XPGs but XPEs were a lot cheaper (like half the price) and I thought they might be an over kill for my tank since I plan to keep things at med tech. Isn't XT-E is better than in effeciency and our use than XPG? I swear these LEDs looks so confusing!


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## TropTrea (Jan 10, 2014)

Tanan said:


> Thanks Troptea. I was thinking of getting XPGs but XPEs were a lot cheaper (like half the price) and I thought they might be an over kill for my tank since I plan to keep things at med tech. Isn't XT-E is better than in effeciency and our use than XPG? I swear these LEDs looks so confusing!


There are available several serries Of LED's in the X rage of single emiters.

From the top down they are
XM-L which runs up to 3,000 ma for 10 Watts. and gives roughly 260lum @ 700ma
XP-G which runs up to 1,500 ma for 5 Watts and gives roughly 240 lums @ 700ma
XP-E which runs up to 1,000 ma for 3 Watts and gives roughly 210 lumns @ 700 ma.

If you look at price though your talking at least twice the price for the XM-L LED's. They are also very hot running when you take them up to 10 watts and also start investing in chip cooling.

With the XP-G's you can run 8 of them at 1,300ma on a channel of 2" X 1" Alumnium without any additional cooling. That would give you roughly 35 Watts of Light good enough for an area of 30" X 10" if your lights are 18" above the water.


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## Tanan (Mar 11, 2009)

So where does XTEs fall?


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## TropTrea (Jan 10, 2014)

Tanan said:


> So where does XTEs fall?


The XT-E R-3 will run up to 1500ma and produces 217 lumuns at 700 ma. 
This series was put on the market in 2010 and was suposed to the best in 2010. 
The XM-L came out later in 2010 but does not include colored LED's
The XM-L2 came out in 2012
The XP-G goes back to 2009


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