90W homemade LED grow

SirJoeDiesel · Aug 23, 2013

i noticed on topledlight that they have xt-e ww 50w modules for like 25USD. Enticing indeed.

edit: thinking maybe two of these with a 30w red/blue in the middle on a nice sink..

Chronikool · Aug 23, 2013

JMD said:
Yea, I've been looking at those. My drivers are only 1000mA though, so I might have to fix some new drivers.
It's fun to test various approaches

For sure....im very impressed with the 50w XPG modules so far....im sure you will be 2.

RedWhiteBlueGreen · Aug 23, 2013

Wow! They are looking very juicy buds!! Delicious!

Might have to read abit more bout these LED's now, as have got an electronics mate who could probably knock me up something easy from your pics & info. Looks cool cheers dude!

Abiqua · Aug 23, 2013

Love the grow JMD.

I have been pondering light bars with a few multichips per bar to cover a 3x3 area.

I have been eying the same Xlamps and this gives me more confidence to DIY some LEDs.

Can you explain the driver setup for a / in a noob fashion. I understand the numbers resulting from current, forward voltage, etc. But the why or the how is never fully explained.

Would this work with a switching power supply [12v 10a 120w] or should you use a switcher only when you have fixed DC drivers [ already and not buck converters?

The power supply options have gotten me confused horribly! I really enjoy your setup and just wanted to ask those questions. Peace!

JMD · Aug 24, 2013

Chronikool said:
For sure....im very impressed with the 50w XPG modules so far....im sure you will be 2.

I should be able to make a 200W LED lamp using the Cree XPG for just about $130 in total. I think that is a very good price, for a high quality lamp, right?

RedWhiteBlueGreen said:
Wow! They are looking very juicy buds!! Delicious!

Might have to read abit more bout these LED's now, as have got an electronics mate who could probably knock me up something easy from your pics & info. Looks cool cheers dude!

Feel free to ask any questions you might have, and I will try to do my best to help

Abiqua said:
Love the grow JMD.

I have been pondering light bars with a few multichips per bar to cover a 3x3 area.

I have been eying the same Xlamps and this gives me more confidence to DIY some LEDs.

Can you explain the driver setup for a / in a noob fashion. I understand the numbers resulting from current, forward voltage, etc. But the why or the how is never fully explained.

Would this work with a switching power supply [12v 10a 120w] or should you use a switcher only when you have fixed DC drivers [ already and not buck converters?

The power supply options have gotten me confused horribly! I really enjoy your setup and just wanted to ask those questions. Peace!

Thanks

The best way to run LEDs is off a constant current source. I don't know your level of electronics knowledge, so I will explain it very basically.

When you connect a lamp to a wall outlet you connect it to a constant voltage source (constant in the sense that it's RMS value stays the same over time). This means that the voltage doesn't change, and that the device you connect decides how much current will be needed. In a constant current source the circuit will adjust the voltage until there flows a specific current, for example 700mA.

With a pure ohmic resistance you you have linear relationship between the voltage and the current. With LEDs this relationship is highly nonlinear. It itself is not a problem, but as the LED gets warmer the voltage across it drops slightly - this results in an increased current, which again increases the temperature.. and there's your thermal runaway, which in the end will destroy your LEDs.

So when the voltage slightly drop as the LED gets warmer, and the current increases, a constant current driver will lower the voltage until the specified current again is achieved - thereby protecting your LEDs.

This, however, does not protect the LEDs against overheating. A simple bi-metal switch can do that though.

Chronikool · Aug 24, 2013

JMD said:
I should be able to make a 200W LED lamp using the Cree XPG for just about $130 in total. I think that is a very good price, for a high quality lamp, right?

Yeah....this was half of the attractiveness of them for me. That and the 'two solder wonder' (and the generous amount of light output of course)

I've been running mine for about 2 and a bit months on constant 12/12...(perceptual) with no problems....it has been a bit of a progression for me and im in the middle of a transition in the style of grow im doing at the moment...take a look im you are interested...?

https://www.rollitup.org/led-other-lighting/600170-chronikool-z-led-organic-sog.html

Abiqua · Aug 24, 2013

JMD said:
I should be able to make a 200W LED lamp using the Cree XPG for just about $130 in total. I think that is a very good price, for a high quality lamp, right?

Feel free to ask any questions you might have, and I will try to do my best to help

Thanks

The best way to run LEDs is off a constant current source. I don't know your level of electronics knowledge, so I will explain it very basically.

When you connect a lamp to a wall outlet you connect it to a constant voltage source (constant in the sense that it's RMS value stays the same over time). This means that the voltage doesn't change, and that the device you connect decides how much current will be needed. In a constant current source the circuit will adjust the voltage until there flows a specific current, for example 700mA.

With a pure ohmic resistance you you have linear relationship between the voltage and the current. With LEDs this relationship is highly nonlinear. It itself is not a problem, but as the LED gets warmer the voltage across it drops slightly - this results in an increased current, which again increases the temperature.. and there's your thermal runaway, which in the end will destroy your LEDs.

So when the voltage slightly drop as the LED gets warmer, and the current increases, a constant current driver will lower the voltage until the specified current again is achieved - thereby protecting your LEDs.

This, however, does not protect the LEDs against overheating. A simple bi-metal switch can do that though.

Big UPS! Thanks....that pretty much nails the why and makes perfect sense, pretty plainly, "So when the voltage slightly drop as the LED gets warmer, and the current increases, a constant current driver will lower the voltage until the specified current again is achieved - thereby protecting your LEDs."

...and by bi-metal switch, I am guessing you mean MOV or a metal oxide resistor switch? That is elec tech all over it. I have been reading!

Now I guess I can read up a little more on differences between transformers, buck converters, switchers, etc and infer why/how they work for controlling the amperage and not the voltage.....if I am following correctly.....

. I am very interested in DIY drivers, but I obviously need to ask some questions, sorry for hacking up your thread, but many thanks!

JMD · Aug 25, 2013

Chronikool said:
Yeah....this was half of the attractiveness of them for me. That and the 'two solder wonder' (and the generous amount of light output of course)

I've been running mine for about 2 and a bit months on constant 12/12...(perceptual) with no problems....it has been a bit of a progression for me and im in the middle of a transition in the style of grow im doing at the moment...take a look im you are interested...?

https://www.rollitup.org/led-other-lighting/600170-chronikool-z-led-organic-sog.html

Your grow looks great mate!

Nice to see that the flood lights work great.

Abiqua said:
Big UPS! Thanks....that pretty much nails the why and makes perfect sense, pretty plainly, "So when the voltage slightly drop as the LED gets warmer, and the current increases, a constant current driver will lower the voltage until the specified current again is achieved - thereby protecting your LEDs."

...and by bi-metal switch, I am guessing you mean MOV or a metal oxide resistor switch? That is elec tech all over it. I have been reading!

Now I guess I can read up a little more on differences between transformers, buck converters, switchers, etc and infer why/how they work for controlling the amperage and not the voltage.....if I am following correctly.....

. I am very interested in DIY drivers, but I obviously need to ask some questions, sorry for hacking up your thread, but many thanks!

It's not a varistor I meant, but this: http://www.ebay.com/itm/250V-5A-KSD9700-65-Celsius-N-C-Bimetal-Thermostat-Temperature-Switch-/181052345876?pt=AU_B_I_Electrical_Test_Equipment&hash=item2a278f8e14

It's composed of a strip of bimetal, which at a certain temperature expands and either makes or breaks a connection (Normally open or normally closed). So for example at 65ºC the above switch would break a connection, which could be used to simply cut the supply to a LED driver.

JMD · Aug 26, 2013

Chronikool said:
Yeah....this was half of the attractiveness of them for me. That and the 'two solder wonder' (and the generous amount of light output of course)

I've been running mine for about 2 and a bit months on constant 12/12...(perceptual) with no problems....it has been a bit of a progression for me and im in the middle of a transition in the style of grow im doing at the moment...take a look im you are interested...?

https://www.rollitup.org/led-other-lighting/600170-chronikool-z-led-organic-sog.html

I'm thinking of going all out.. a 720W LED lamp would cost me roughly 400 USD to build. That isn't that bad..

Chronikool · Aug 27, 2013

JMD said:
I'm thinking of going all out.. a 720W LED lamp would cost me roughly 400 USD to build. That isn't that bad..

Cool beans....[video=youtube;vc7VBVpl1SY]http://www.youtube.com/watch?v=vc7VBVpl1SY[/video]

Made up of multi chips? That would be number one!!!

JMD · Aug 27, 2013

Chronikool said:
Cool beans...

Made up of multi chips? That would be number one!!!

Would be 12x 50W warm white Cree XPG modules and 4x 30W Red/blue Cree XPG modules.

Bumping Spheda · Aug 27, 2013

My 50W Warm White runs at ~60W... before the CPU fan.

Actually, I'm a bit drunk, so I don't remember the numbers 100%, but, well I was surprised... I'd try to limit these suckers via the driver you choose, they just keep on pulling. My veg tent is rolling around in Watts I didn't know about.

Edit:
Brought to you by my recent access to a Kill-A-Watt meter; made possible by my brother.

JMD · Aug 27, 2013

Bumping Spheda said:
My 50W Warm White runs at ~60W... before the CPU fan. Actually, I'm a bit drunk, so I don't remember the numbers 100%, but, well I was surprised... I'd try to limit these suckers via the driver you choose, they just keep on pulling. My veg tent is rolling around in Watts I didn't know about.

Edit:
Brought to you by my recent access to a Kill-A-Watt meter; made possible by my brother.

That sounds odd. At 1500mA they should drop about 3.25V each. With 10 in a string that would be 32.5V x 1500 mA = 48.75W.
Maybe if you drive them at around 1750 mA, I think they would eat 60W.

Bumping Spheda · Aug 27, 2013

Just checked. My 50W Warm White is being driven by a Meanwell LCP60-1750... Ack. Shoulda payed attention to the eBay listing, I guess. :wall:

Okay. So pay attention to the driver you buy, otherwise you'll draw 60W... :dunce:

JMD · Aug 27, 2013

Bumping Spheda said:
Just checked. My 50W Warm White is being driven by a Meanwell LCP60-1750... Ack. Shoulda payed attention to the eBay listing, I guess. Okay. So pay attention to the driver you buy, otherwise you'll draw 60W...

I think I made a very good guess there!

With the few LED modules I already have, I would have to buy:

12x 50W warm white Cree XPG modules (22 USD each)
12x 1500mA LED drivers (35 RMB each)
4x 500x120x20mm heatsink (45 RMB each)
1x 30W red/blue LED module (22 USD)
4x 1000mA LED drivers (25 RMB each)

I'm thinking of dropping the 30W modules, because they are most likely 630nm (the blue I don't know) - which the warm white should cover just fine. So instead of those, I could add some 660nm modules.

Chronikool · Aug 27, 2013

JMD said:
I think I made a very good guess there!

With the few LED modules I already have, I would have to buy:

12x 50W warm white Cree XPG modules (22 USD each)
12x 1500mA LED drivers (35 RMB each)
4x 500x120x20mm heatsink (45 RMB each)
1x 30W red/blue LED module (22 USD)
4x 1000mA LED drivers (25 RMB each)

I'm thinking of dropping the 30W modules, because they are most likely 630nm (the blue I don't know) - which the warm white should cover just fine. So instead of those, I could add some 660nm modules.

If i were you i wouldn't run the 50 watters at their max... more like 700-1000 mA

Reasons: Life of LED increased, less heat, more efficient, less cost on drivers and heatsinks.

And i dont think you lose to much in light output dropping the Amps down. You can also double up (or more) drivers for 1 XPG module

Also i would grab 2 x cool white XPG's to put in there....for a bit more blue.

All my opinion of course...

JMD · Aug 28, 2013

Chronikool said:
If i were you i wouldn't run the 50 watters at their max... more like 700-1000 mA

Reasons: Life of LED increased, less heat, more efficient, less cost on drivers and heatsinks.

And i dont think you lose to much in light output dropping the Amps down. You can also double up (or more) drivers for 1 XPG module

Also i would grab 2 x cool white XPG's to put in there....for a bit more blue.

All my opinion of course...

Going down to 1000mA form 1500mA makes you loose about 100 lumen per LED. 12 modules with 10 LED each means I would loose 12000 lumen - what that relates to in PAR I don't know, but I'm sure it's significant.

But I have ideas for that

lax123 · Aug 28, 2013

lumenwise i think there is a rule of thumb for low mA ranges: 2x lumens = 2,6x needed power input =decreased efficiency, +more cooling and expensive heatsinks needed

JMD · Aug 28, 2013

lax123 said:
lumenwise i think there is a rule of thumb for low mA ranges: 2x lumens = 2,6x needed power input =decreased efficiency, +more cooling and expensive heatsinks needed

Yep, lower efficiency, but you will need fewer LEDs - so you gotta choose what you want.
Heat shouldn't be a problem, and the heatsinks are cheap.

Still trying to figure out how I want it to look. My first simple draft (500x480mm of heatsink area):

lax123 · Aug 28, 2013

looks really nice, which programm did u use?

Regarding the pictures in the first post: did u start from seed with full power 72W?

Also, why did it work so great, so many ppl here r like screaming u need "white" for all sorts of things going on in the plants and yellow and green and so on...saying with just red and blue the plant is missing something...

Why r those heatsinks cheap, you have a good source? Or what do you consider cheap, a 500x500 heatsink would be here like 120$, thats like 180W of led modules

edit, oh just saw that "green" etc was already mentioned

90W homemade LED grow

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