Noob needs help with grow light

Thread Starter

rammplins

Joined Aug 3, 2017
2
Hello everyone, this is my first post on here so bear with me if I do something wrong. I am planning on a 180w grow light system, after reading up online I have created a diagram that I think will work. I just need help figuring out what size fuses to use, and where to put the dimmer switch. Also let me know if the setup itself is safe. The LED's will be mounted onto 6 1ft aluminum heatsink rails that will have 2 or 4 fans blowing on them(not sure yet).
Thank you in advance!

pieces for grow light
18- 10w 9-11v 900-1000ma Full spectrum COB LED's
6- ?a fuses
1- 21-34v 6a constant current LED driver
1- 200w dimmer switch
?- resistors
 

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ebeowulf17

Joined Aug 12, 2014
2,945
Unless I'm misreading something, you've got 18 lights that 1 amp each, so 18 amp total current draw if you utilize full potential of lights. However, you've only got a 6 amp power supply, which would appear to be 1/3 of what you need. Are you intending to run the lights well below their state current rating?

Also, unless the LED driver is some special configuration meant to run off of a dimmer (which would be new to me,) the dimmer and the LED driver will be fighting each other.

Do you have a part number and datasheet for the driver you have in mind?
 

bertus

Joined Apr 5, 2008
20,104
Hello,

@ebeowulf17 , I also have my doubts about the dimmer arrangement.
There are led drivers that allow PWM dimming.

Also for balancing, a resistor of 1 - 2 Ohms 5 Watts, could maybe used.

Bertus
 

Thread Starter

rammplins

Joined Aug 3, 2017
2
The dimmer was just more of an idea than a must, and the dimmable drivers are either not powerful enough or out of my price range.
as for the resistor is that one resistor per string or is that 1 resistor for the whole circuit? And where would it go? right after the leds in the string?

here is the specsheet for the driver : https://www.aliexpress.com/store/product/Constant-Current-LED-Driver-6000mA-DC-21-34V-200W-7-10-20-AC-100-240V-0/1913069_32826571160.html?spm=2114.12010612.0.0.5c775fdetI3NO0

and as for the fuses im thinking of using a 6-Way Lateral Single Fuse Box with 1amp - 32v fuses. and are the fuses necessary?
fuse box specs :https://www.amazon.com/dp/B000VU9D1G/_encoding=UTF8?coliid=I2WCK9ZVPC7OT3&colid=1KFEHSBH3KUE2

Thanks again everyone!
 

Andrei Suditu

Joined Jul 27, 2016
51
Don't know if it helps but, can't he run the LEDs at their rated voltage without resistors(with a variable buck regulator ) and then use a mosfet with a PWM generator to adjust brightness?
 

bertus

Joined Apr 5, 2008
20,104
Hello,

I would not use fuses in a system with a current source.
When one fuse blows, the other branches will get more current and will likely also blow (if the leds don't burn out earlier).

Bertus
 

ebeowulf17

Joined Aug 12, 2014
2,945
Don't know if it helps but, can't he run the LEDs at their rated voltage without resistors(with a variable buck regulator ) and then use a mosfet with a PWM generator to adjust brightness?
I had thought of that too, and I wondered if the rapid switching of load would affect performance of the current regulator. This isn't something I have tons of experience with, but every time so far that I've seen circuits like this, pwm control is integrated into an led driver chip, or it's simply not used. I've never seen a current source being switched downstream with pwm. I have no idea of this would present a problem or not, or maybe this is a common technique that I just haven't come across yet.

Come to think of it, maybe the reason I haven't seen this is because most current sourcing circuits have a readily available means of adjusting the current limit, so if you want brighter or dimmer, you can just change your current setting.
 

ebeowulf17

Joined Aug 12, 2014
2,945
Hello,

I would not use fuses in a system with a current source.
When one fuse blows, the other branches will get more current and will likely also blow (if the leds don't burn out earlier).

Bertus
That's a really interesting point. Hadn't thought of that!
 

Andrei Suditu

Joined Jul 27, 2016
51
I had thought of that too, and I wondered if the rapid switching of load would affect performance of the current regulator. This isn't something I have tons of experience with, but every time so far that I've seen circuits like this, pwm control is integrated into an led driver chip, or it's simply not used. I've never seen a current source being switched downstream with pwm. I have no idea of this would present a problem or not, or maybe this is a common technique that I just haven't come across yet.

Come to think of it, maybe the reason I haven't seen this is because most current sourcing circuits have a readily available means of adjusting the current limit, so if you want brighter or dimmer, you can just change your current setting.
Probably if the source outputs has some decent caps it should work.In the end the caps will Smith the current spikes at switching and the regulator should've mind anyway because most can regulate without load.
 
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