Using XP-Gs and XT-Es on the same driver?

[tgunn]

I just got my 24 LED RapidLED kit with:
9 Cool White Cree XP-G R5 LEDs
15 Royal Blue Cree XT-E LEDs

I'm essentially going to be splitting this between the two drives and using them on two tanks.

I just realized though, the different LEDs have different operating currents. Am I totally off the ball on this idea? I understand that setting the driver current sets it so each LED gets the same current. I presume I'd need to drive all them around the 800-900mA range. Am I going to be horribly short-changing myself with the whites then?

Ie the specs from RapidLED.com say:
Cree XT-E (Blue, Royal Blue, Green) 1000mA max
Cree XP-G (Neutral and Cool White) 1500mA max


Thanks!
Tyler

 

[der_wille_zur_macht]

In the March datasheet, Cree retroactively raised the limit on XT-E LEDs to 1.5A. Apparently some of the reef vendors haven't caught on to that yet since it appears that several are still claiming the max is 1A.

Go ahead and put them on the same driver, if you want. Adjust current to give you the intensity you need (we really can't predict that for you with any degree of accuracy). In theory those drivers max out at 1.3A so you should be fine for both models of LED.

The only real shame in doing this is that you won't have control over the individual colors, but if you get the ratio of LEDs correct that's not a huge deal.

 

[tgunn]

In the March datasheet, Cree retroactively raised the limit on XT-E LEDs to 1.5A. Apparently some of the reef vendors haven't caught on to that yet since it appears that several are still claiming the max is 1A.

Go ahead and put them on the same driver, if you want. Adjust current to give you the intensity you need (we really can't predict that for you with any degree of accuracy). In theory those drivers max out at 1.3A so you should be fine for both models of LED.

The only real shame in doing this is that you won't have control over the individual colors, but if you get the ratio of LEDs correct that's not a huge deal.

Thanks for that info der_wille; that makes a HUGE difference!

I'll start by setting the current conservatively; I did get the 0-10V dimmable driver so I could adjust the overall brightness. I used a 1.5 royal blue to 1 cool white ratio. I know there's a zillion other possible permutations but I figured I'd start with this and see how I like the color.

If it turns out the blue is too over powering, I can always order a couple of the smaller drivers and break the white and blues on to separate circuits. I won't consider that a waste as the larger driver can always be used on a future tank. Perhaps I'll pre-wire the blues and whites into separate strings from the start and just join these two into a single string prior to hooking up to the driver. Then it'll be easier to split them in the future if need be.

Thanks!
Tyler

 

[der_wille_zur_macht]

Another option if you don't like the color would be to add one or two additional LEDs to each string, i.e. a warm white or something like that. You've got plenty of headroom in terms of Vf for those drivers - could probably fit another one or two LEDs on each.

Either way, wiring the LEDs in different "strings" and/or leaving space on the heatsink would be prudent to allow future expansion.

 

[tgunn]

Another option if you don't like the color would be to add one or two additional LEDs to each string, i.e. a warm white or something like that. You've got plenty of headroom in terms of Vf for those drivers - could probably fit another one or two LEDs on each.

Either way, wiring the LEDs in different "strings" and/or leaving space on the heatsink would be prudent to allow future expansion.

I should have ample room on the driver. I'm planning to start with 10 LEDs over the tank right now (10g nano with LPS/softies).

I built a mount for the LEDs out of 1" wide U channel alum:

My current thought was to lay them out somewhat like this on the 3 rails:

RB CW RB

CW RB RB CW

RB CW RB

There is enough room between the 3 rails for me to add another 2 in the future. Hmm, maybe I'll just add another 2 rails to start. I have LOADS of the C-channel alum.

I'm going to duct an 80mm fan into an acrylic splash-guard to actively cool the LEDs and protect them from the humidity and salty air of the canopy.

THanks,
Tyler

 

[tgunn]

As a followup; I set the current to 1000mA for my string. WOW, this is insanely bright over the 10g nano tank.
The downfall I ran into is that with the 60degree optics the LEDs came with, the tank had a pretty bad "disco effect". I pulled all the optics off (just put 'em on with a tiny bit of white glue) and cranked up the brightness again. This significantly reduces the disco effect. The tank is also more evenly lit; I'd probably prefer the light more focused toward the middle. But that's okay. It's still incredibly bright; more than bright for LPS/softies as I plan for this tank.

I'll definitely need to put my vent fan in; the canopy traps the LED heat quite well. The heat sink never gets "untouchable", but it gets warm enough I'd consider it almost "hot".

Thanks again for the advice!

 

[kcress]

I'll definitely need to put my vent fan in; the canopy traps the LED heat quite well. The heat sink never gets "untouchable", but it gets warm enough I'd consider it almost "hot".

This would probably heat your tank too. Vent = good idea.

 

[tgunn]

This would probably heat your tank too. Vent = good idea.

I'll probably go ahead with my original plan and duct a higher velocity fan over the LEDs, which will be in their own little separate compartment sealed from the water surface. I'll also use a slower fan to provide some general air exchange and airflow for the water surface.

The LEDs are sure a different animal from the T5 and halide light i'm familiar with.
I loved halides for the strong shimmer, and T5s for the lower heat. The LEDs give an ever stronger shimmer and have low heat. Seems like a winning combination to me!

 

[kcress]

Yeah LEDs are IT now. You probably don't need high velocity. Just some movement will make a giant difference. Likely a lot quieter too.

 

[Alexis58]

I'm essentially going to be splitting this between the two drives and using them on two tanks

 

[tgunn]

I got my led plenum built. An 80mm fan on the back is ducted with an acrylic box into the led area:

The splash shield acts to divert the air up to a slot on the top. I built it so I can slide it out for easy cleaning

A close up of the led fan duct on the back (splash guard removed).

The other fan provides general canopy ventilation.

Finally I built a black acrylic box to hide the slit on the front edge of the canopy

I will definitley be buying a new 80mm fan for the led area. I only had one low rpm fab so I jusy pulled one from the misc box. Woooow I forgot how loud pc fans used to be!!!! The plus is the heat sink remains cool to touch all the time.

We will see I guess. My nano is at work and there is a decent amount of white noise from my coworker testing industrial pc components and from the robot room down the hall.

 

[kcress]

Personally I would never bother building a LED canopy for a gas grill..






Seriously, it's clean and well thought out. I like it!

 

[tgunn]

Personally I would never bother building a LED canopy for a gas grill..



Seriously, it's clean and well thought out. I like it!

Hahah, awesome, I thought I had cropped the gas grill box out of the picture. Yeah, I don't know if it would be able to stand up to THAT much heat.

Thanks! I'm quite pleased with how it turned out.

Here it is installed on the tank:

I have to admit, I REALLY enjoyed working with acrylic. For whatever reason the pieces I cut fit together easily, and the Weldon 16 made it a cinch to just press them together into the finished product almost instantly.

I think I'll give a try at building more interesting acrylic creations in the future.