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Cree 5.2 help


pencile

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looking at the builds for the cree 5.2 I see that most are using 1 set of meanwell 1000hw (5 each) to run two 5.2's. is this correct? If so that would be running these led's at about ( if my math is right) 50% of their rated output or less. If using the 700's and 1000's on a one to one basis (one driver for each row) one can get closer to 75%. What is the right/ best way to go? I have a 125 gal reef tank and was thinking about using 5 5.2's.

The other question, depending on the first, is regarding the Storm x controller. Can the controller have two pwm inputs to the same channel? That is, can I take the PWM outputs from two drivers and put them on the same storm x channel? understanding both drivers would act the same.

Thanks for your input!!

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Meanwell LDDs are the drivers of choice at the minute and work well with the 5.2 units.

 

LDD drivers don't have PWM output, they receive input. So putting multiple drivers on one PWM output from say a storm controller will make all the drivers on that channel dim and brighten the same.

 

As for numbers of 5.2's for your tank I'm not sure, I went old school and used individual Cree diodes as opposed to these new multi chip PCBs. I think spread would be the deciding factor, you don't want a couple of shafts of light in your tank so more is better.

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I would use 700mA drivers for channels 1, 4, and 5. 1000mA for channels 2 and 3.

 

Reason? Channels 1, 4 and 5 use LEDGroupBuy's exotic LEDs which are only rated at 700mA. You don't want to pulse an extra 300mA in there. If properly cooled it might work (I've heard of XM-L diodes being run at 6A before) but given the cost of the board not something I'd risk.

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jedimasterben

No, those LEDs will not tolerate that extra 300mA even with excellent cooling. The 3535 package chips are much more efficient at taking heat out of the LEDs, but it isn't enough to give extra current lol.

 

OP, unless your tank is tall, a single bank of 700mA LDD are all you'll need for all five channels. Standard 125g tanks are 72x18x24, so if you keep the LEDs 8" off the top of the tank, that gives a 32" distance. I have PAR readings for that distance here: http://www.nano-reef.com/topic/343127-lumia-52-pics-and-par-readings/

 

Drivers only have PWM input, not output. A single pin of the Storm X can be used to control up to ~133x LDD.

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