XP-G vs XM-L

[daplatapus]

I've been reading TONS of these thread's on RC and am very slowly starting to think I might be getting a handle on how to build my DIY hood. As I was looking for a Canadian source for my LED's I was told to check out these guys.

http://www.ledgrouptext removed.

The XP-G in cool white is rated 3w, 1500ma, 139lm where the XM-L's are 3w, 3000ma, 260lm. That's for the T-5 model, the T-6 is 280lm but it's a fair bit more expensive.
It would seem that with the doubled ma (1500 vs 3000) you could run more LED's per string, hence cutting down on controlers?
And being over 50% brighter you should be able to use less, albiet probably with a wider lense?
Has anyone had an opportunity to use these yet? Any recommendations?

 

[kcress]

A problem I've not heard a solution to is how you equitably mix royal blues with those much brighter XMLs. You also have to be on your A-game with the heatsinks if you want to crank XMLs.

 

[jcgd]

You can use half the number or even a third of the number of XML so heat shouldn't be an issue if you have a heatsink. I'm using XML in my new build so I can let you know how it goes.

 

[Jimmy54]

I am using the XM-Ls. (still building my fixture)
The thing is, almost everyone is running the the XP-G @ 1A which wil put out around 260 lm.
The XM-L will put out a little more lumens @ the same current using less volts, and because of that, less watts.
So the XM-L is more efficient. You won't notice much difference on your electricity-bill when you're using 10 or 20 XM-Ls instead of 10-20 XP-Gs. But on larger fixtures with 64 of them, like the one I am building, I guess you will notice the difference. That's the reason why I'm using XM-Ls instead of XP-G.

As for buying less XM-Ls vs XP-G - half as much is mentioned - I'm not so sure. You might go with a few XM-Ls less, running them @ 1.5A or 2A without lenses, but with half the amount of XM-Ls you will probably need to run them at full power - @ 3A - 9/10 watt -1000lm.
The only way to go with half as much XM-Ls vs XP-Gs and keep your corals from burning at the same time, is by hanging the fixture against the ceiling using 10 or 20 degree lenses.
Did you ever see 18 XM-Ls - just to give you an idea.

 

[daplatapus]

Hmmm, good thoughts, some I never considered. Like how to mix the brighter XM-l's with the dimmer Royal blus XP-G's. Thanks for bringing that up.
jcgd: thanks for the heads up. I just couldn't figure out what that whole clay boa was about. I was pulling my hair out! But now I can't figure out how to remove that link. ( I wonder why it's banned? Should I be buying anything through them?)

Jimmy54: HOLY CRAP that's bright! Maybe too bright to try and focus on my tank. It's going to be a 135 gallon on a stand in my dining room with an 8' ceiling. There's only so far I can get it away from my tank lol. Maybe I can give my fish sunglasses....

 

[jcgd]

My built is for freshwater but I'm using 6 XML on each pendant, four pendants and 40 degree optics. Each pendant should give me around 500 umols of par running at 2000mA at 48" away. That is a ballpark number but should be pretty close. I also have 3 royal blue xpe and 3 neutral white xpg on each pendant with 60 degree optics for color rendering and extra light running at 1000mA max. I will have 8 strings of 6-7 LEDs all independently controlled and fully dimmable from full on to about 2% of full brightness.

Although my build is designed for plants I have no doubt I could grow sps. My tank is 72 x 24 x 22".

 

[Jimmy54]

I've got my 20 XM-L NWs from them. (I am going to use 16)
At that time they were the only one offering XM-L NWs - and for a very reasonable price. So, no problems if you don't need you're stuff right away.

But I've got my 70 RBs and 3 PWM controllers from RapidLed, and that went a lot faster

 

[colevasseur]

I am using the XM-Ls. (still building my fixture)
The thing is, almost everyone is running the the XP-G @ 1A which wil put out around 260 lm.
The XM-L will put out a little more lumens @ the same current using less volts, and because of that, less watts.
So the XM-L is more efficient. You won't notice much difference on your electricity-bill when you're using 10 or 20 XM-Ls instead of 10-20 XP-Gs. But on larger fixtures with 64 of them, like the one I am building, I guess you will notice the difference. That's the reason why I'm using XM-Ls instead of XP-G.

As for buying less XM-Ls vs XP-G - half as much is mentioned - I'm not so sure. You might go with a few XM-Ls less, running them @ 1.5A or 2A without lenses, but with half the amount of XM-Ls you will probably need to run them at full power - @ 3A - 9/10 watt -1000lm.
The only way to go with half as much XM-Ls vs XP-Gs and keep your corals from burning at the same time, is by hanging the fixture against the ceiling using 10 or 20 degree lenses.
Did you ever see 18 XM-Ls - just to give you an idea.

Hi, the Xm-L put out around 160 Lumens per Watt at 350mA (http://cutter.com.au/products.php?cat=Cree+XM-L) while the XPG put out around 114 lm per Watt at the same current (same source).

Also, if I run XPG at 750 mA and Xm-L at 1,5 A (both at half capacity so heat should not be a problem) I should get around 171 lm for the XPG and at least 500 lm for the Xm-L.

Calculations : (source : Cutter.com)

XPGs
Since XPG delivers 114 lm/W at 350 mA and 92 lm/W at 1500 mA, it should deliver a value somewhere in between at 750 mA. But let's say here they still deliver 114 lm/W at 750 mA, Its a total of 114lm/W X 1,5W = 171lm (at half capacity).

XM-L
Since Xm-L delivers 100 lm/W at 3000 mA and 160 lm/W at 350 mA, it should deliver a value in between at 1500 mA. But here let's say it only delivers 100 lm/W at 1500 mA, we get 100lm/W X 5W = 500 lm (at half capacity).


In this case, should 1 Xm-L be worth around 3 XPGs? Remember that we underrated Xm-Ls and overrated XPGs in the calculations.

Do these calculations make sense to you!?

 

[Jimmy54]

Since XPG delivers 114 lm/W at 350 mA and 92 lm/W at 1500 mA, it should deliver a value somewhere in between at 750 mA. But let's say here they still deliver 114 lm/W at 750 mA, Its a total of 114lm/W X 1,5W = 171lm (at half capacity).

The XP-G R5 gives 139 L/W @ 350mA. So .35 x 3Vf = 1 watt = 139 lumens.
At 750mA it is .75 x 3.2Vf = 2.4 watt. Multiply that with let say 120 lumens = 300 lumens at half capacity - not 171 lumens

XM-L
Since Xm-L delivers 100 lm/W at 3000 mA and 160 lm/W at 350 mA, it should deliver a value in between at 1500 mA. But here let's say it only delivers 100 lm/W at 1500 mA, we get 100lm/W X 5W = 500 lm (at half capacity).

You might be right with this one

However, half capacity means 4.5 watt for the XM-L against 2.4 for the XP-G.
So .... now we need to look at what we really need or want; is it 500 lumens from a singel LED?
or would we be better off with 2 LEDs delivering 300 lumens each, spreading more than enough light over a larger area and consuming .3 watt's more?

In this case, should 1 Xm-L be worth around 3 XPGs? Remember that we underrated Xm-Ls and overrated XPGs in the calculations.

In this case that would be a no.

 

[TheFishMan65]

I just went through the math on the main LED thread. I ran a couple possibilities, but I concluded that N XP-Gs are better than N/2 XM-Ls for efficiency (lumens / watt).

So IMHO I would go with the XP-Gs. Given the prices it will be about the same cost for N XP-G vs N/2 XM-Ls. You will use less electricity with the XP-Gs. You will have to worry about spread less.

 

[kcress]

I'm with the FishDude. Unless you have special circumstances, I don't see a lot of advantage to the L over the G. Probably the next thing out will be a big enough efficiency/brightness step that it will make compelling sense.

If you were just into white only LEDs and wanted to mount them to ceiling the L's would be da bomb as you could have a much smaller fixture. If you wanted the blue-heavy look it would be a lot harder.

 

[pwreef]

Yeah definitely consider spread as well. I just built a fixture with Bridgelux leds and when built the first one I bunched them close together. Even with optics it did not look good, so I had to re-do one of the fixtures. All this LED stuff is definitely an experiment. If you really want to use XMLs look at how Maxspect built their new fixture. Perhaps that will give you some ideas. And using more current (1.5A vs 3A) does not mean less drivers. It means more drivers or more expensive ones because you need more power. Also you do not want to run XMLs at 3A. That will make them heat too much and wear out quickly. Its like running the engine in your car at max RPM all the time. Of course it can do it, but thats not a good idea.