Optimal LED for 4x4x7, 2 plant SCROG


#82

Where are you measuring the Temps of 92 and 74 at?


#83

Hi @dbrn32, the 92F was at the floor of the tent. Since that post I’ve been able to bring the temp down to 85. I’m working to bring it lower. The 74 was taken at knee level in the grow room. Since I’ve moved the thermometer to the inside of the inlet fan to see what the actual temp going in is.

I took a measurement of the wall wattage taken by one set of 3 COBs. They are drawing 290 watts. I thought it would be higher with the inclusion of the Mean Well driver… That’s 72.5 watts/sqft at max brightness. Now I’m happy knowing I have plenty of light.

All the lights were burning for an hour or so before I heard my wife holler “what happened”. She had tripped the breaker while running a hair straightening iron and hair dryer. I’ve ordered a third timer… It’s time to utilize the 3rd circuit in the room.


#84

The driver is rated based on max voltage output. Do you know what forward voltage of your cob is at 1.4 amps? I assumed they were 52 volt vero, but they look like they would be more like 70 volt C version. 70 volts x 1.4 amps Puts you right about there.

Did you use a kilawatt to measure them? Also, if you’re using a potentiometer to dim with, opening the dimmer circuit will give you a little boost in output, up to 108%. But you have more light than you need, so I wouldn’t worry too much about it.

Your Temps aren’t too bad. Probably a tad higher on the floor because there’s not as much air moving there. But you should be plenty good with mid 70’s at canopy level I would think.


#85

@dbrn32 - its mid 70s outside the tent, mid 80s on the inside where the plant is.

I started a separate thread here
Feeding A/C into tent? about venting an A/C unit into the tent.


#86

Yes. Just plug it in and measures. Perfect for a hacker like me.


#87

Here’s what I settled on:
Truedays 16" Plant Saucer Caddy, Plant Dolly With Wheel Roller Moving Tray Pallet

I was able to get two of them for 30.00 (used) at a garage sale, and they’re pretty darn sturdy, too. The water storage space is really nice, though I still have to be careful how I pour (it seeps as well as drains), but it works, and I can use it for the Christmas this year.:slight_smile:


#88

Here’s what I settled on:
Truedays 16" Plant Saucer Caddy, Plant Dolly With Wheel Roller Moving Tray Pallet

I was able to get two of them for 30.00 (used) at a garage sale, and they’re pretty darn sturdy, too. The water storage space is really nice, though I still have to be careful how I pour (it seeps as well as drains), but it works, and I can use it for the Christmas this year.:slight_smile:


#89

Those are neat, but not sure what they have to do with the lights I was talking about?


#90

Wow! Far more affordable than I thought :thinking: and I’ll be able to purchase sooner than planned :smiley:


#91

That light is only 185watts


#92

I don’t understand why people don’t seem to take efficiency and heat dissipation, etc. into account when evaluating the output of LEDs. If a light is pluming off heat, that’s part of the draw at the wall. Electricity from the wall does not evenly equate to lumens from the light. An incandescent bulb that burns 60W puts out light+heat. An LED that burns 9W puts out approximately the same amount of light+a lot less heat.

Maybe I’m misreading.


#93

Some people do. Some people even go as far to say that a 9 watt led has about 10-15% driver efficiency loss, and out of the 7 or 8 watts remaining less than half of those will be par watts while the rest go to heat loss. The same people also probably aren’t concerned at all with the amount of lumens a particular light measures. The only time lumens would be taken into account is when calculating efficacy of two lights that produce exactly the same light spectrum. Otherwise the amount of lumens produced is relatively worthless.

Not everyone has a degree or even any experience at all in light science, engineering, or even an electrical background. That’s why we try to help each other out. For most, it simply doesn’t matter because they don’t have the budget for a highly efficient led light. In those cases you just try to find the best for which you can afford.


#94

@dbrn32 thanks and I agree about being helpful. Sorry if my post came off differently. I mentioned it more because it seemed like consensus vs. individual misunderstanding. But I appreciate your addition.


#95

I didn’t think your post came off as bad or anything like that. But you only really touched on the beginning of led efficiency. There are a few of us here that could really take that conversation to the next level if you want. But the almighty dollar usually runs the average hobby grower out of the conversation quickly.


#96

I’m at a loss when it comes to lighting. Don’t even understand most of what’s posted about it…
I have a 1000w HPS in a tent that’s 4.75x4.75x6.75 and have been told that it’s perfect and that it’s too much :thinking:
I’m using T5 florescent for veg (for economy sakes more than anything) but will switch to the HPS for flower.


#97

You’re 1000 watt is fine in that size grow. A lot of people struggle to maintain canopy temps with them, so they opt for other options.

A lot of people underestimate how good fluorescent is for veg. Outside of going with a more efficient led setup, I would definitely consider fluoro’s as my next option. I think you’re pretty good right where you’re at.


#98

One good trick for a hefty HID lamp like that is to connect your exhaust fan with flexible duct right to the lamp fixture, so the air around the bulb goes out the exhaust. You can also get really fancy with special glass that reflects infrared (heat mirror). Probably too expensive for hobby growing, when LEDs are relatively cheap.


#99

Put them in a tote I got a washing machine pan under all mine it’s gets water in it and I shop vac it up


#100

I’m very new at growing. Last year i tryed 320 watts of cfl. It was a loser.

I just got King 3x dimmable 900 watt for a 4x4 grow room I built in my man cave. It looks good, but we’ll see.


#101

Looking at King’s specs for other LEDs I think those “900 watt” LEDs only draw about 152 watts each from the wall. So you would have 456 watts total. 456/16 is 28.5 watts per square foot. 35 would be better. 28.5 will probably do. Make sure your walls are all painted with flat white paint to get maximum reflection.

If you could buy two more of these lights it would be near ideal. Or maybe I’m wrong about the power draw. I didn’t actually find a spec for the 900 watt model. I estimated that from the power draw of their “1800 watt” model.