LED FAQ) Building and DIY

[exploziv]

so why is it being suggested to use this for 36v cobs?

Don't know the answer to that, but 36V will burn that. Max voltage is 24V..

For dimming 36V cobs I recommend using arduino board (or compatible) with pwm pins, optoisolators and mosfet transistors.

I am not sure if it´s good for dimming leds i doubt its the right way to dim them i think it can confuse the constant current driver. Somebody should try.
It´s a pwm regulator, it works with chopping the power in small onoff sections so the voltage is the same but on off all the time so the average power is lower than full power. It is used to regulate dc motors with ie. Rc cars etc and is fine for a dc fan.
My English is terrible to explain technical stuff.

Rilla.

If that's working with PWM, then yeah, it can be used to variate 12V fans speed. But the product description says nothing about pwm, it says it will dim from 0 to 8 A at 12-24V.
And they say nothing about power limits on input ports. Meaning that is you use a 12V 10A PSU to power that, the output would be actually dimmed from 0 to 10A, and the thing will probably get burned when you get over 8A.
So it's a very vague description if that's the case.

Just read the description again, and I found this:

Constand voltage and constand current output, can be connected with amplifiers to extend its load

Guess that means it can't be PWM based, cause that won't be constant voltage, since PWM goes from 0 to MAX voltage multiple times per second.
That, or the description is for another product.. LOL.

 

[Dion]

one more thing, but where is the potentiometer to control out-voltage in this driver https://www.meanwell-web.com/en/adv...words=hlg-185h-c1400a&search_in_description=1 ?

i'm noob i think i'll buy a led kit from china , DIY is not easy hahahah

the data sheet shows there is a screw that you can turn to dim

a DIY kit from china is absolutely the worst waste of money

good luck

 

[ivan2015]

Don't know the answer to that, but 36V will burn that. Max voltage is 24V..

For dimming 36V cobs I recommend using arduino board (or compatible) with pwm pins, optoisolators and mosfet transistors.



If that's working with PWM, then yeah, it can be used to variate 12V fans speed. But the product description says nothing about pwm, it says it will dim from 0 to 8 A at 12-24V.
And they say nothing about power limits on input ports. Meaning that is you use a 12V 10A PSU to power that, the output would be actually dimmed from 0 to 10A, and the thing will probably get burned when you get over 8A.
So it's a very vague description if that's the case.

Just read the description again, and I found this:

Guess that means it can't be PWM based, cause that won't be constant voltage, since PWM goes from 0 to MAX voltage multiple times per second.
That, or the description is for another product.. LOL.

so.. what you raccomanded for dimm fans ? a computer psu ATX ?

 

[ivan2015]

the data sheet shows there is a screw that you can turn to dim

a DIY kit from china is absolutely the worst waste of money

good luck

 

[GoeRilla]

Don't know the answer to that, but 36V will burn that. Max voltage is 24V..

For dimming 36V cobs I recommend using arduino board (or compatible) with pwm pins, optoisolators and mosfet transistors.



If that's working with PWM, then yeah, it can be used to variate 12V fans speed. But the product description says nothing about pwm, it says it will dim from 0 to 8 A at 12-24V.
.

Can´t know for sure but they say:
PWM digital dimming, avoid rush current, protect your LED lights
Never know about Chinese goods though, they like to use the sexy words.

Rilla.

 

[exploziv]

so.. what you raccomanded for dimm fans ? a computer psu ATX ?

A computer PSU will not dim fans. It can just power them.
You need a 12V power source, i recommend to get a small power supply instead of a big computer psu.
Then, for dimming you can use this for up to 4 independent controlled fans:
http://www.ebay.com/itm/3-5inch-PC-...602580?hash=item25af958894:g:0vwAAOSwwbdWIHNp

You can probably find others for 1 fan if you need, or maybe even find some cheap speed controller like this in a local pc shop if you don't want to order it on ebay.

Or you can uses the one we were discussing earlier if you need one or multiple fans varied at same speed. http://www.ebay.com/itm/12V-8A-LED-...id=100009&rk=1&rkt=1&mehot=pp&sd=110909230030

@GoeRilla, yeah you are right, that description is really bad. But I looked at the description of the more expensive one that's the same product and it's much better explained. So yeah, it's pwm. Good only for 12/24V DC fans or 12/24V led strip or 12/24V strings of leds protected by ressistors. DO NOT USE THAT WITH led/driver combo or with MORE than 24V!

 

[ivan2015]

DO NOT USE THAT WITH led/driver combo or with MORE than 24V!

if u don't use that(http://www.ebay.com/itm/12V-8A-LED-...id=100009&rk=1&rkt=1&mehot=pp&sd=110909230030) with driver combo , how can i use that if it works with 12-24 input voltage ?

(how can you edit posts ? )

 

[Dion]

the cheapest easiest and best way to dim DC fans like pc fans is a ac/dc converter with adjustable volts like

http://www.conrad-electronic.co.uk/...c-75-Vdc-9-Vdc-12-Vdc-600-mA?ref=searchDetail


that one will run 12 fans easily for 3 euro extra you get 1500mA( dunno perhaps 30-40 fans?)

this is actually the one i use to run all the fans on heatsinks(on the timer with the lights)

then i have the 1500mA running all the circulation and extraction 24/7

you rig ur fans in paralel and dim with a screwdriver

doesnt get better than that

if u don't use that(http://www.ebay.com/itm/12V-8A-LED-...id=100009&rk=1&rkt=1&mehot=pp&sd=110909230030) with driver combo , how can i use that if it works with 12-24 input voltage ?

(how can you edit posts ? )

how can i tighten a screw with a hammer?

 

[exploziv]

if u don't use that(http://www.ebay.com/itm/12V-8A-LED-...id=100009&rk=1&rkt=1&mehot=pp&sd=110909230030) with driver combo , how can i use that if it works with 12-24 input voltage ?

(how can you edit posts ? )

I meant to not use it with led drivers that are constant current. for fans it's ok. you have a 12V power source connected on the input and fans connected in paralel on the output. simple to set up.

@Dion, most pc fans (8 to 12 cm size) need 100-350 mA, so 1500 mA are nowhere near 20-30 fans. It's better to just read the power consumption on the fans (sometimes you need to google the model to find out, but most of the times it's written on the center of the fan, on one of the sides), and look for the mA or A rating.
From there you just add the mA of the fans, if you got more than one and you get a power source that can run a bit over that current.

let's say you got 2 fans that draw 150mA each, that equals 300 mA or 0.3 A (1000 mA = 1 A). You need a 0.5 A (500 mA) power source for that. The extra is there because you don't want to run psu's at full power and to allow for the dimmer draw (~100 mA) if you decide to use one.

@ dion, in my experience those shitty wall plug variable transformers are never good for their rated voltages, like sometimes 3 V is 5 V, 9 V is 12 V and 12 V is 18 V and so on. This is why I stopped using them and i'm using only regulated (stabilised) power supplies. That being said, have you checked yours with a multimeter?

@ivan You can edit posts after you get to be a member with full rights, at 50 posts.

 

[ivan2015]

I agree with @explosiv ,is it better better not to trust in that cheaply wall plug trasformer , i hope dion has right and he has checked volts with a multimeter.

If i want assembly a LED ,has sense if a take a driver dimmable? Or i can avoid it and take a driver like that @dion suggested some post ago, same version , but not dimmable ? LED's light 8x CX3070 is very powerful , some times i need to do something under the lights .. i think if i can dimm down the lights for a moment , this will be confortable .
What s your opinion?

 

[exploziv]

Depending on how many leds there are connected per driver, you could just use less of them if you need less light and not get the dimmable versions. But if you feel you need it, get the dimmable ones.

 

[Koondense]

I have a dimmable HLG led driver and would never buy a non-dimmable one.
U can have many more options with a dimmable driver. I like more options for a similar price.

About cheap dc transformers, I used and tested many and never had trouble with any of them. The one I use now is similar to the one Dion posted above and it puts out voltage with max +/-5% difference(at 9V it's 9,02V), which is nothing if you use it for fans. I tested a 1500mA version with 6 fans and still have plenty of current to use if I want to add more fans(max around 30 fans I think.
Maybe the one you used exploziv had a too powerful load for the rated output current, then it can go kaput. Or maybe it was bad before...


*maybe anyone knows how to build a proper DIY fan controller for 220V AC?

 

[exploziv]

They were cheam chinese ones, and they were bad when i bought them. Every one i tried was out of specs. But we do have crappier chinese electronics here than in other parts of the world, so it's possible the ones you guys buy are better quality.

 

[jesbuds]

I agree with @explosiv ,is it better better not to trust in that cheaply wall plug trasformer , i hope dion has right and he has checked volts with a multimeter.

If i want assembly a LED ,has sense if a take a driver dimmable? Or i can avoid it and take a driver like that @dion suggested some post ago, same version , but not dimmable ? LED's light 8x CX3070 is very powerful , some times i need to do something under the lights .. i think if i can dimm down the lights for a moment , this will be confortable .
What s your opinion?

You can wire in some switches for your lights so you can turn them off in sets of 2 (or whatever), fairly easy to do.

 

[ivan2015]

Build a led it's not easy , i haven't experience , i think i wll buy LED builded for grow

 

[TexMex McDirt]

I started a separate thread with my questions, but thought I'd throw them in here too. I am planning to build out a new grow space and a new slightly larger flower cab for it and I want to migrate from CFL to LED. I have been reading thru LED threads here and also on other forums for a few weeks now, but I just haven’t been able to get a firm grasp on the COB technology. I am a pretty smart guy, but I get lost with complex electrical talk, it is not my strongest suit. So I am asking for help from you LED folks. I have a number of specific questions and I welcome and thank you for any and all feedback.

The new flower cab will be 16”x24”, about 2.6 square feet. I plan to continue running a perpetual micro SOG but I may switch to a modular SCRoG later. I have been toying with either using the screw in LED bulbs or COBs. I really like the ease and simplicity of the screw in LED bulbs. But I think the COBs are just better overall. Better light, less heat (this is really important to me), more efficient, etc.. So…

How close can the COBs get to the girls without burning or bleaching? I really won’t be able to give up much headroom for this and I know the screw in LED bulbs can be very close without any burning or bleaching like CFLs. If I have to account for 12” between the COBs and the tops of the girls this could be a deal breaker.

I know a COB LED light consists of the COB, a driver and a heatsink/fan. The heatsink/fan I got covered. I would probably go with individual heatsink/fans like the Arctic Air 11 for each COB. I don’t think I have any questions on that piece. That may be the only part I have firm grasp of.

How many COBs would be needed for the 16”x24” cab for either SOG or SCRoG? I know how to figure out watts and lumens for the CFL and LED bulbs, but am a bit lost on the COBs. I keep reading that the CXA3070 is a really good COB. Would that fit my needs?

So, if I know what COB and how many, then there’s the drivers. Do I need one driver per COB or, depending on how many COBs I need for the cab, could I run them all on one driver? Should it be dimmable or should I just get drivers that would run the COBs at the right amps/watts? I keep reading that the COBs should be run at about 50% power for efficiency. Is that right?

Is the wiring of the driver to the COB and also to the power source pretty straightforward? Do the drivers come pre-wired to a power plug or would I need to splice into like an extension cord?

That’s all I have for now. I really appreciate anyone that takes the time to read this and provide me some help as I make the move into the future with LEDs!

 

[ivan2015]

As first i say i m not expert , dion has not reply you yet .. so i want just share my experience you ,
For a space like that i think you need 1x CX3070 5000k (http://eu.mouser.com/Search/m_Produ...4Prknbu83y0bObCPMgyC/AAZag4DB6D4TpVpI9Ddrqg==) , u turn on this for veg ,
and you need 3x of this CX3070 3000k http://eu.mouser.com/Search/m_Produ...4Prknbu83y0bObCPMgyC/l6eQby5L/DGQDb9TViwpOg==) ,
Those works with maximum voltage 38.5v , so for driver you can choose if take 1 driver for cob or 1 driver for 2 COBs. Those are best perfomance/$
I think is better 2 driver with max Output volt 80v 1500mA (38.5v +38.5v u can keep turn on 2 COBs), 1500mA is racommended for efficency and life's LED.
So 1,5Ax(38.5+38.5+38.5+38.5)= 220w
U get 220w led which for a space 40cmX60cm (right? I am european) is well
U can get driver dimmable (Mean well are good), but they are more expensive , if i you had a dimmable , you never come back with a non dimmable , by the way , you can put in a simple switch for turn off the lights
I REPEAT , I AM A NOOB , NOT TAKE WHAT I WROTE SERIOUSLY, WAIT DION OR ANOTHER
I hope i had help you
Bye bye

 

[Koondense]

My theory would sound like this.

2,6 sq feet needs around 100W of cob leds with high efficency for a good flowering if you target around 40W/ft².
You can achieve this with less or more cob units, all depending on your budget and height of grow space.
Less cobs-lower build price, more cobs-better efficency(softer driven).

Best options are 2x 50W, 4x 25W, also 3x 37W and some more of course

I would get Cree CXB3070 or Vero18(29) cobs, of colors around 3000K to 5000K for full cycle, you can combine colors for a broader spectral distribution.
For two leds get a MeanWell HLG-120H-C1400A(is actually 150W max but dimmable and can drive less leds for start), for more leds get a lower current driver like HLG-120H-C1050A or C700A(handle 3-6 leds at once - depending on model)

As said, it all depends on your budget and growroom height.

 

[Dion]

I started a separate thread with my questions, but thought I'd throw them in here too. I am planning to build out a new grow space and a new slightly larger flower cab for it and I want to migrate from CFL to LED. I have been reading thru LED threads here and also on other forums for a few weeks now, but I just haven’t been able to get a firm grasp on the COB technology. I am a pretty smart guy, but I get lost with complex electrical talk, it is not my strongest suit. So I am asking for help from you LED folks. I have a number of specific questions and I welcome and thank you for any and all feedback.

The new flower cab will be 16”x24”, about 2.6 square feet. I plan to continue running a perpetual micro SOG but I may switch to a modular SCRoG later. I have been toying with either using the screw in LED bulbs or COBs. I really like the ease and simplicity of the screw in LED bulbs. But I think the COBs are just better overall. Better light, less heat (this is really important to me), more efficient, etc.. So…

How close can the COBs get to the girls without burning or bleaching? I really won’t be able to give up much headroom for this and I know the screw in LED bulbs can be very close without any burning or bleaching like CFLs. If I have to account for 12” between the COBs and the tops of the girls this could be a deal breaker.

I know a COB LED light consists of the COB, a driver and a heatsink/fan. The heatsink/fan I got covered. I would probably go with individual heatsink/fans like the Arctic Air 11 for each COB. I don’t think I have any questions on that piece. That may be the only part I have firm grasp of.

How many COBs would be needed for the 16”x24” cab for either SOG or SCRoG? I know how to figure out watts and lumens for the CFL and LED bulbs, but am a bit lost on the COBs. I keep reading that the CXA3070 is a really good COB. Would that fit my needs?

So, if I know what COB and how many, then there’s the drivers. Do I need one driver per COB or, depending on how many COBs I need for the cab, could I run them all on one driver? Should it be dimmable or should I just get drivers that would run the COBs at the right amps/watts? I keep reading that the COBs should be run at about 50% power for efficiency. Is that right?

Is the wiring of the driver to the COB and also to the power source pretty straightforward? Do the drivers come pre-wired to a power plug or would I need to splice into like an extension cord?

That’s all I have for now. I really appreciate anyone that takes the time to read this and provide me some help as I make the move into the future with LEDs!

hey

the answer to a lot of your questions are it depends(koondense has elaborated on what you need as far as power goes)

ill try answer ur questions best i can

1)How many COBs would be needed for the 16”x24” cab?
depends on what cob u use-have a read of the micro diy led thread in my sig

2)Do I need one driver per COB or, depending on how many COBs I need for the cab, could I run them all on one driver?
depends what driver u use and what cobs u wanna run

a good driver with dimming could run up to 200w so enough for your flower space but they cost around 60 bucks so using a non dimming chinese driver is cheaper- id advise u run all lights in flower off a dimmable driver and all veg cobs of a cheap one

3)Is the wiring of the driver to the COB and also to the power source pretty straightforward? yes. if i can do it anyone can

4)Do the drivers come pre-wired to a power plug or would I need to splice into like an extension cord? splice to an extension cord



you wont need 12 inches(thats ilke 30cm?) i like my cobs bout 20cm from the canopy- if u want to have the cobs closer just use more smaller cobs then u can keep them almost touching
in simple terms 50w of light from a single source will get pretty hot at 3 inches away
instead try 5x10w cobs-close as you want em
another way to save headroom especially with using smaller chips is not use a pc heatsic fan combo(they r like 2 icnhes thick) instead use a heatsink profile with a pc fan on it(1 icnh?)

cree cobs require cob holders for mounting and for electrical connection0 the reason they r the "best"is because they r so efficient
but in a small build you can get same/ better efficency running veros soft so that is a good option for you

agian take a look at the micro link below

id recomend u spend 100 bucks at digikey on chips wires grease and screws then get heatsinks from heatsinkuse and drivers from jamico or whatever

 

[TexMex McDirt]

Thanks for the feedback guys.

Keeping the COBs 20cm (about 8 inches) from the canopy should work fine for me. That's not too much space to give up.

I think 3 COBs will work to cover the 16"x24" space. This will be for flower only, not veg. I am leaning towards the Cree CXA3070 3000k. Like This one. Does that seem like a good choice?

I think 1 driver per COB, like the Mean Well LPC-60-1400. Does that make sense?

Lastly, mounting each COB on it's own heatsink. The ARCTIC Alpine 11 seems to be a good choice.

So, if I built 3 COBs like that, would that be sufficient for the 16"x24" space? What mistakes am I making?

Thanks!