New member with light question.

Living in beautiful Southern Oregon.
I am growing Northern Lights and we only do edibles (mostly canna caps), for a good nights sleep. (I suffer from RLS) so this really helps, and my wife has problems with insomnia.
I have been growing for just one year.
I am just finishing my third indoor grow, and tried an outdoor grow last summer.

So my setup.
I have two homemade cabinets, one for cloning and a little veging, 2x3x3
My main cabinet is 2x3x4ft.
This is how it originally was built.

Since then the mods.
Remove that tiny ass heater ind install a chicken coop heater like this.
https://www.amazon.com/Cozy-Products-Chicken-Heater-Brooder/dp/B01LX9K1JI/ref=sr_1_4?gclid=CjwKCAiAx_DwBRAfEiwA3vwZYumnDMBSI2XcjXIhmuZYJPInu0fcNCwm693y8fs3tLsSk7MkyU0YLBoCCHsQAvD_BwE&hvadid=174233456587&hvdev=t&hvlocphy=9033112&hvnetw=g&hvpos=1t2&hvqmt=e&hvrand=17668105687670845426&hvtargid=kwd-11785707188&hydadcr=24656_9648981&keywords=chicken+coop+heater&qid=1578939707&sr=8-4

This is controlled by a thermostatically controlled outlet (i have it set to 60°f)
I also added a second PC fan, i now have two of these for exhaust.

https://www.amazon.com/Antec-TriCool-Cooling-3-Speed-Switch/dp/B00066ISFC/ref=sr_1_1?keywords=Tri+cool+pc+fan&qid=1578939893&sr=8-1

They are always on and can be adjusted from 39 to 79 cfm each.
I also have a simple 6" fan hanging at the top blowing across my canopy.
I have five ea. 21/2" vents cut into the bottom on the opposite side from the exhaust fans.

As you can see I have a homemade CFL light fixture pushing 300w of light.
Two different bulbs 2700k and 6500k.
For my last grow (currently 8 weeks in flower), i built a scrog screen 2" squares.

So I am wanting to get an LED setup, and have about settled on an HLG 260w qb.
https://horticulturelightinggroup.com/collections/all/products/260w-qb-led-kit?variant=14546842681393

This is in a 3500k full spectrum.

My last harvest was about 3oz off of two plants.
I want to try and improve the yield and quality of my buds.
I am thinking that the hlg 260 is big enough to completely cover my space, and it is dimmable.
Couple of concerns, how do I know how close to put this light to my plants?
Also if heat is a problem can I mount the driver on the outside of the cabinet?

Thought I would finish with pictures of my current grow.



Any help is greatly appreciated.

the 260 would be about perfect for that 2x3. 40ish watts per sq ft with led is spot on.

and those airy/fluffy buds you have with the cfl will tighten up and your yield should increase drastically.

rkymtnman said:

the 260 would be about perfect for that 2x3. 40ish watts per sq ft with led is spot on.

and those airy/fluffy buds you have with the cfl will tighten up and your yield should increase drastically.

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thanks for the quick reply.
So how do you tell if your light is to close?
Do you think I could set the height and leave it, only adjusting the dimmer?
Also should I leave the driver mounted to the heatsink (or gain a few inches by mounting it on the outside)

SoMike said:

So how do you tell if your light is to close?

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it will be much brighter than what you got. you'll just have to judge by the plants reactions i.e. light bleaching. having the dimmer will be good for sure.
it's always best to max out your height in your cab so do whatever you can to accomplish that. it seems like you got the plant training under control so that's a bonus.

rkymtnman said:

the 260 would be about perfect for that 2x3. 40ish watts per sq ft with led is spot on.

and those airy/fluffy buds you have with the cfl will tighten up and your yield should increase drastically.

Click to expand...

This right here... It would be awesome in your space!!!

rkymtnman said:

the 260 would be about perfect for that 2x3. 40ish watts per sq ft with led is spot on.

and those airy/fluffy buds you have with the cfl will tighten up and your yield should increase drastically.

Click to expand...

Still a good harvest you have ahead of you!!! I'm always impressed by CFL grows!!!

Frank Nitty said:

This right here... It would be awesome in your space!!!View attachment 4455676

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Might just be the light, but those plants kind of look like they've got a zinc deficiency.

spek9 said:

Might just be the light, but those plants kind of look like they've got a zinc deficiency.

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Some kind of deficiency for sure... Using Megacrop v2 and cal mag... But then I'm feeding these the same thing!!! All autos in tupur...

Can you post some pics with the lamp off?

So the 260 w qb has a dimmer and I am assuming it reduces the voltage to the led?
If i want to dial in a specific watt per sqft say 40 watts, how would I do that?

I'd lay some aluminium foil on top of your current light rack. Your CFLs emit in all directions so you'll probably boost your canopy intensity by reflecting the light that's facing away from the plants back down ontop. Cool setup

SoMike said:

So the 260 w qb has a dimmer and I am assuming it reduces the voltage to the led?
If i want to dial in a specific watt per sqft say 40 watts, how would I do that?

Click to expand...

Watts = Volts × Amps

Example:
10V × 2A = 20W

Your grow is a constant size, so determine how many watts per ft2 you want and multiply that number by your grow size. Then its as easy as measuring the voltage and current flowing from your driver. A $8-$10 multimeter is all you'll need. You'll adjust dim level with your "Io POT" found on the driver, or "current potentiometer." In electronics the capital letter "I" means current (amps), "Io" means current output. The voltage shouldn't change as much as the current. Youtube how to measure voltage and current with a multimeter or watch a similar vid and wire in a small permanent digi to give you a Voltage/Current measurement anytime you desire.

ChiefRunningPhist said:

Watts = Volts × Amps

120V × 2A = 24W

Your grow is a constant size, so determine how many watts per ft2 you want and multiply that number by your grow size. Then its as easy as measuring the voltage and current flowing from your driver. A $8-$10 multimeter is all you'll need. You'll adjust dim level with your "Io POT" found on the driver, or "current potentiometer." In electronics the capital letter "I" means current (amps), "Io" means current output. The voltage shouldn't change as much as the current. Youtube how to measure voltage and current with a multimeter or watch a similar vid and wire in a small permanent digi to give you a Voltage/Current measurement anytime you desire.

Click to expand...

Ok so first off the 260w qb only has a single dimmer screw.
So the multi meter is wired in series with the output leads going to the qb.
I will verify the exact voltage then check the amps using the v x a = watts
So if i want 37 w per sqft then I should have 3.1 amps at 120v.

First thing I notice when the lights too close or bright, is the points on the edges of the upper leaves will twist upwards if that makes sense. My guess would be 14”-24” would be your range with that fixture.

SoMike said:

Ok so first off the 260w qb only has a single dimmer screw.
So the multi meter is wired in series with the output leads going to the qb.
I will verify the exact voltage then check the amps using the v x a = watts
So if i want 37 w per sqft then I should have 3.1 amps at 120v.

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Oh ok, sorry for the confusion. In your example of 37W/ft2, you can achieve that 37W in many different combinations.

Some possible ways to achieve 37W:
1V × 37A = 37W
2V × 18.5A = 37W
10V × 3.7A = 37W
37V × 1A = 37W
74V × 0.5A = 37W
Ect...

So 120V × 3.1A = 372W

LEDs are non linear devices meaning that their voltage doesn't maintain a linear or constant proportionality to their current. Once a certain voltage is met they flow current at an exponential rate there afterward. Because of this you'll end up tuning your light to your desired wattage per ft2 mostly via current regulation. If you want 37W/ft2, determine how many total watts that will mean for your space first. For example, if your space is 3ft2, then you'd need a total of 111W, (37W/ft2) × (3ft2) = 111W. After you determine total wattage needed, you'd then want to determine what your voltage is when the board is on and running. Due to the non linear relationship, once the light is on, the V shouldn't change much. Then it's simple algebra.

You'd set your V variable to whatever V you measured, and you'd set your W variable to your desired wattage:

W = 37W/ft2
V = whatever you measure
I = ?

W = V × I
37 = (V) × ?
37 ÷ (V) = ?
I or ? = 37/V

So your current that you'll want to tune your light will be equal to 37W/ft2 divided by the voltage you measure.

Voltage can be done by just touching the probes on an energized cct, or in parallel, but like you said you'll have to wire the multimeter in series to measure the current. Make sure your positive probe or wire is plugged into the 10A terminal on your multimeter when checking current (because you'll be measuring more than 200mA). When it comes to voltage, the V with the squiggly looking sign is for AC voltage, and the V with the straight line is for DC. Your wall voltage will be 120VAC if you live in the states, but what's important is the voltage being output by the driver going to your light.



(also, I'm sure I'm just being redundant but Watts = Volts × Amps, not Volts × mA. So 48V × 325mA = 15.6W, or 48V × 0.325A = 15.6W)

Typically it's the current that you want to regulate when it comes to LED arrays. Ill have to look to see what driver they are using. If it's a meanwell with only 1 POT, then there should be 2 dimmer leads that could be wired with an aftermarket POT in series to regulate current flow.

SoMike said:

So the 260 w qb has a dimmer and I am assuming it reduces the voltage to the led?
If i want to dial in a specific watt per sqft say 40 watts, how would I do that?

Click to expand...

A really simple way is to work out the square footage of your cabinet and times it by 40w, 30w or whatever you want to run at, to get the total wattage for the entire cabinet. Then buy a power meter (uk) or a Kill a watt (USA) for about a tenner and plug it into the mains socket the light is plugged into. Then adjust the dimmer on the 260w qb until it reads the correct total wattage on the power meter.

There might be a slight difference due to performance of the driver not being 100%, but it is close enough for general growing. That will also show you how much your grow is costing in real time. Saves having to do maths every time you alter the power up or down and having to wire in a multi-meter. Literally plug and play.

It's not oregano said:

A really simple way is to work out the square footage of your cabinet and times it by 40w, 30w or whatever you want to run at, to get the total wattage for the entire cabinet. Then buy a power meter (uk) or a Kill a watt (USA) for about a tenner and plug it into the mains socket the light is plugged into. Then adjust the dimmer on the 260w qb until it reads the correct total wattage on the power meter.

There might be a slight difference due to performance of the driver not being 100%, but it is close enough for general growing. That will also show you how much your grow is costing in real time. Saves having to do maths every time you alter the power up or down and having to wire in a multi-meter. Literally plug and play.

Click to expand...

That is what I was thinking about.
I think i really could figure out the math but it was making my head hurt.
Ill find one of those kill a watt devices
Thanks.

It's not oregano said:

A really simple way is to work out the square footage of your cabinet and times it by 40w, 30w or whatever you want to run at, to get the total wattage for the entire cabinet. Then buy a power meter (uk) or a Kill a watt (USA) for about a tenner and plug it into the mains socket the light is plugged into. Then adjust the dimmer on the 260w qb until it reads the correct total wattage on the power meter.

There might be a slight difference due to performance of the driver not being 100%, but it is close enough for general growing. That will also show you how much your grow is costing in real time. Saves having to do maths every time you alter the power up or down and having to wire in a multi-meter. Literally plug and play.

Click to expand...

Very nice, lol much easier...

Bobby Long Buds said:

First thing I notice when the lights too close or bright, is the points on the edges of the upper leaves will twist upwards if that makes sense.

Click to expand...

Interesting, I had that once.