Need help driving 70 1W Cree SMD LEDs - The Planted Tank Forum
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post #1 of 72 (permalink) Old 12-05-2016, 10:12 PM Thread Starter
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Need help driving 70 1W Cree SMD LEDs

Hey guys,

I'm going to do it, I'm going to build the ultimate ( but not crazy featured, no lightning and sun up and sun down and no fluffy unicorn effects ) DIY LED light for my 75 gallon, details to come, still in the homework and research phase.

What I need help with is how to power 70 of these Cree 1W LEDs. The ebay listing says they are 1-3W, not sure what that means...

Im going to use:

50x 6000k
10x red
5x green
5x 3000k

I want them to be dimmable, all on one channel. Simple.

Hoping to get the parts off ebay, so if you could provide the ebay listing number, that would be great.

As far as I know, all I need is a driver and a dimmer?

Thanks for any help!

here is the listing for the LEDs im looking at
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Last edited by Sean W.; 12-06-2016 at 12:50 AM. Reason: .
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post #2 of 72 (permalink) Old 12-05-2016, 10:59 PM
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Watt rating of diodes is kind of a game.. Basically what current they can handle..

Say you have a 3.3 V(f) diode and drive it at 300mA or 900mA.. If it can survive 900 ma it is a "3W" LED.. if not and survives best at 300mA it is a "1W" LED

As 2 drivers and dimmers.. well need the V(f) of your diodes and what you want to run them at.
As to dimmer, manual or not?

If you want to run them at constant voltage it requires terminal resistors..

If you run them constant current you will need to run parallel strings or multiple drivers.. Makes one channel dimming a bit difficult..

How much work do you want to do at modifying ebay parts?

I need to mention, as my standard suggestion, skip green unless you get cyan (or plan on using "just green" for something, you can't "fake" cyan w/ out blue), deep red (660nm) is better than red..

70 x 3.3 (231V so you can't (shouldn't) run all as one string.. x 350mA = 81W

Point is even "simple" has multiple approaches..
Secondly, since you can't run one string, single channel dimming is kind of a waste of technology.

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post #3 of 72 (permalink) Old 12-05-2016, 11:02 PM Thread Starter
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Quote:
Originally Posted by jeffkrol View Post
Watt rating of diodes is kind of a game.. Basically what current they can handle..

Say you have a 3.3 V(f) diode and drive it at 300mA or 900mA.. If it can survive 900 ma it is a "3W" LED.. if not and survives best at 300mA it is a "1W" LED

As 2 drivers and dimmers.. well need the V(f) of your diodes and what you want to run them at.
As to dimmer, manual or not?

If you want to run them at constant voltage it requires terminal resistors..

If you run them constant current you will need to run parallel strings or multiple drivers.. Makes one channel dimming a bit difficult..

How much work do you want to do at modifying ebay parts?

I need to mention, as my standard suggestion, skip green unless you get cyan (or plan on using "just green" for something, you can't "fake" cyan w/ out blue), deep red (660nm) is better than red..

70 x 3.3 (231V so you can't (shouldn't) run all as one string.. x 350mA = 81W

Jeff, glad youre here to help. Sorry I forgot to post a screenshot of the ebay Leds im planing on using. Not sure if that changes anything from your first post?

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post #4 of 72 (permalink) Old 12-06-2016, 12:29 AM
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I did a DIY LED fixture recently using similar LEDs so I'll share what I learned. First of all I'd suggest a "constant current" LED driver that can handle your load; this gives you a number of advantages including not messing with resistors, power stability and maximum lifespan. To determine the voltage you need, add up the forward voltage for all the LEDs in your array - your proposed setup has 60 at 3.2-3.6V (white and green) and 10 at 2.1-2.4V (red) for a total of 213-240 volts. The next thing to do is decide on your desired power, since these can be run at 350 to 1000 mA that means they can be 1W, 2W or 3W LEDs. Based on that decision you'll end up needing a power supply (or supplies) capable of delivering 70, 140 or 210 watts. However, you don't want to drive your power supply at 100% all the time, so you need one with enough juice that your anticipated load is only 60-80%-ish of capacity. This means you'd need a 100W driver for 70x 1W LEDs rather than just getting a 75W driver and calling it good.

The other option is running multiple drivers. Say you split your array in half with 35 LEDs per driver at 1W each. Now you only need 35W of power and your voltage requirement drops to 110-120 VDC. Plus, if you get multiples of the same driver you should be able to dim them equally with the same dimmer connected to both drivers. I got my drivers from LED Drivers - Phihong, Mean Well, MagTech, LUXdrive & More but I can't find any powerful enough for your application that are dimmable, so you may have to make a couple smaller arrays.

If you use a constant current driver, my advice would be to not run parallel strings off the same supply. Let's say you have two strings of 2W LEDs in parallel each drawing 700 mA. This requires a 1400 mA power supply and everything runs fine, but if you lose an LED in either string, that entire string will shut off and all the current gets dumped through the other one that's still working. Since 1400 mA is way over what the LEDs are rated for, you could basically create a snowballing failure and burn out a bunch of LEDs. I ran all my lights in series and when I lose one the whole array shuts off, but it's easy to pull it out (I used screws instead of glue) and I know none of the other lights will have fried.

I actually registered just to post this so I hope it was helpful

Edit: Be very careful about electrical safety when messing with these things. 30V is generally considered the beginning of unsafe voltages for people and you're going to be working well beyond that with currents that are potentially lethal. Not trying to scare anyone out of trying a DIY setup - mine works fantastically and I love it - just don't want to see anyone get hurt.
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Last edited by BigMek; 12-16-2016 at 08:06 PM. Reason: Grammar whoops.
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post #5 of 72 (permalink) Old 12-06-2016, 12:30 AM
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No, just sort of confirms what I said. do you want to drive the diodes "soft" or hard??
350 or 1000mA..

Ignoring the red and green for a moment..(btw they seem to have 660nm red if you ask) your output is like 55w or 165W..

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post #6 of 72 (permalink) Old 12-06-2016, 12:33 AM Thread Starter
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Okay, so after watching this video:

www.youtube.com/watch?v=UlM5uvO7sao&t=82s
It looks like all I would need is a driver that meets the following requirements:

Input voltage: 110-220v
Output Voltage: at least 238v
Output Amperage: 1000ma

and all I would need to do to dim them is to be able to control the Output amperage between 300ma and 1000ma.


Yes?
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post #7 of 72 (permalink) Old 12-06-2016, 12:46 AM Thread Starter
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oops sorry guys didnt see these posts, you both must have posted while I was composing my last reply

Quote:
Originally Posted by BigMek View Post
I did a DIY LED fixture recently using similar LEDs so I'll share what I learned. First of all I'd suggest a "constant current" LED driver that can handle your load; this gives you a number of advantages including not messing with resistors, power stability and maximum lifespan. To determine the voltage you need, add up the forward voltage for all the LEDs in your array - your proposed setup has 60 at 3.2-3.6V (white and green) and 10 at 2.1-2.4V (red) for a total of 213-240 volts. The next thing to do is decide on your desired power, since these can be run at 350 to 1000 mA that means they can be 1W, 2W or 3W LEDs. Based on that decision you'll end up needing a power supply (or supplies) capable of delivering 70, 140 or 210 watts. However, you don't want to drive your power supply at 100% all the time, so you need one with enough juice that your anticipated load is only 60-80%-ish of capacity. This means you'd need a 100W driver for 70x 1W LEDs rather than just getting a 75W driver and calling it good.

The other option is running multiple drivers. Say you split your array in half with 35 LEDs per driver at 1W each. Now you only need 35W of power and your voltage requirement drops to 110-120 VDC. Plus, if you get multiples of the same driver you should be able to dim them equally with the same dimmer connected to both drivers. I got my drivers from LED Drivers - Phihong, Mean Well, MagTech, LUXdrive & More but I can't find any powerful enough for your application that are dimmable, so you may have to make a couple smaller arrays.

If you use a constant current driver, my advice would be to not run parallel strings off the same supply. Let's say you have two strings of 2W LEDs in parallel each drawing 700 mA. This requires a 1400 mA power supply and everything runs fine, but if you lose an LED in either string, that entire string will shut off all the current gets dumped through the other one that's still working. Since 1400 mA is way over what the LEDs are rated for, you could basically create a snowballing failure and burn out a bunch of LEDs. I ran all my lights in series and when I lose one the whole array shuts off, but it's easy to pull it out (I used screws instead of glue) and I know none of the other lights will have fried.

I actually registered just to post this so I hope it was helpful

Edit: Be very careful about electrical safety when messing with these things. 30V is generally considered the beginning of unsafe voltages for people and you're going to be working well beyond that with currents that are potentially lethal. Not trying to scare anyone out of trying a DIY setup - mine works fantastically and I love it - just don't want to see anyone get hurt.
Thank you for registering just to post that reply, I really appreciate it!

Quote:
Originally Posted by jeffkrol View Post
No, just sort of confirms what I said. do you want to drive the diodes "soft" or hard??
350 or 1000mA..

Ignoring the red and green for a moment..(btw they seem to have 660nm red if you ask) your output is like 55w or 165W..
Without knowing the light out put, im not sure if im going to have to drive them hard or soft. I might end up running them at 350ma to get the desired light output, or I might need to run them at 800+ma to get what I need, Im not sure. Im going to have to build it and adjust the light to my needs.
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post #8 of 72 (permalink) Old 12-06-2016, 12:49 AM
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I agree that constant current w/ LDD's (some Avail. on the bay) IS the way to go.
But JUST to show you how to "create" a Beamswork Bridgelux type array.
Problem is you can't mix V(f)'s easily.. Would need a separate designed "leg" for like the red:


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post #9 of 72 (permalink) Old 12-06-2016, 01:03 AM Thread Starter
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Quote:
Originally Posted by jeffkrol View Post
I agree that constant current w/ LDD's (some Avail. on the bay) IS the way to go.
But JUST to show you how to "create" a Beamswork Bridgelux type array.
Problem is you can't mix V(f)'s easily.. Would need a separate designed "leg" for like the red:
I think we both posted at the same time, I want to make sure you saw my other posts jeff?

I guess my question now is there a way of constantly supplying 238+Volts while raising or lowering the amps to control brightness?

-Sean
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post #10 of 72 (permalink) Old 12-06-2016, 01:08 AM
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ESt. of your diodes @1W each...no lenses.. 47.5PAR @ 50cm (19.7")


Quote:
* MIXING LIST
----------------------------------------
Cree XP-E Green (520-535nm) [120°] x5
Cree XP-E Red (620-630nm) [120°] x10
Cree XP-E CoolWhite (5000-10000K) [120°] x50
Cree XP-E WarmWhite (2600-3700K) [120°] x5
----------------------------------------

* SIMULATION DATA
----------------------------------------
Luminous flux : 7,754 lm
Radiant flux : 24,556 mW
PPF : 111 umol/s
TCP : 4760 K
CRI : 98
λp : 633 nm
Color : #FFCEA7
----------------------------------------

* PERFORMANCE @ 50cm
----------------------------------------
Irradiance : 10.4 W/mē/s
Illuminance : 3,291 lx
PPFD : 47.5 umol/mē/s
----------------------------------------

by SPECTRA 1.0β @ 1.023world
SPECTRA

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post #11 of 72 (permalink) Old 12-06-2016, 01:15 AM Thread Starter
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Quote:
Originally Posted by jeffkrol View Post
ESt. of your diodes @1W each...no lenses.. 47.5PAR @ 50cm (19.7")
what wattage would I need to run them at to get around 100 par at 21" to substrate
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post #12 of 72 (permalink) Old 12-06-2016, 01:33 AM
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Calculator doesn't work that way. but roughly doubling the drive current (2W) should get you close.
2/3.4 =588 mA. Just double the diode count..
I suspect your pretty set in 1000mA. Just be aware that your heat load will be somewhat problematic. Nothing earth shattering though..
I'd suggest 750mA Ldd-h's for a constant current setup. 1 driver per every 12or 13 diodes..
As I said earlier, dimming gets a bit "complicated' though I did find a manual dimmer w/ both constant voltage pwm and a 5v pwm "port'.
Haven't seen it reail beside alibaba or new zealand..
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post #13 of 72 (permalink) Old 12-06-2016, 01:41 AM Thread Starter
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Quote:
Originally Posted by jeffkrol View Post
Calculator doesn't work that way. but roughly doubling the drive current (2W) should get you close.
2/3.4 =588 mA. Just double the diode count..
I suspect your pretty set in 1000mA. Just be aware that your heat load will be somewhat problematic. Nothing earth shattering though..
I'd suggest 750mA Ldd-h's for a constant current setup. 1 driver per every 12or 13 diodes..
As I said earlier, dimming gets a bit "complicated' though I did find a manual dimmer w/ both constant voltage pwm and a 5v pwm "port'.
Haven't seen it reail beside alibaba or new zealand..
If I can get away with constant everything, and have the brightness be where I need it, that would be ideal. Even more simple and easier to make. So I'm not set on 1000mA driver(s).

I fund this MeanWell driver, could I use this one to power everything at once, constant voltage and amperage?

200W, 700mA, 286v
https://www.amazon.com/PowerNex-HLG-...l+hlg+185h-700
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post #14 of 72 (permalink) Old 12-06-2016, 01:42 AM
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change your diode count to 72 and run 6 serial rows w/ one ldd per row. 48V power supply @ 5A or more..
Don't see any currently on the bay though. and ldd's are 700mA or 1000mA

Count really isn't crucial,just symmetry..
W/ constant current you can mix colors
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post #15 of 72 (permalink) Old 12-06-2016, 01:43 AM Thread Starter
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Quote:
Originally Posted by jeffkrol View Post
change your diode count to 72 and run 6 serial rows w/ one ldd per row. 48V power supply @ 5A or more..
Don't see any currently on the bay though. and ldd's are 700mA or 1000mA

Count really isn't crucial,just symmetry..
W/ constant current you can mix colors
... You lost me here...

This is the housing im going to be using, 48" version

MakersHEATSINK SLIM | MakersLED
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