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# Lights, Voltages, Lumens, and Wavelengths

#1
09-17-18, 09:29 PM
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Lights, Voltages, Lumens, and Wavelengths

So I have a few questions.
• How can I learn the true power pulled from lights that are LED, CFL bulbs, or the longer T8 style bulbs? Maybe like kW/h or something, it all seems hard to line up when different lights I.e. LED, CFLs, or incandescent.
• How is Voltage related to the power a standard household breaker is set up with, i.e. 15 amp standard breakers I think?
• How can I safely calculate how many different things I can plug into a surge protector and then plug that into a single standard three prong outlet? ( I don't want to unnecessarily be using other outlets to avoid overloading another, and vise versa.)
Obviously I plan on growing plants under them, indoors, and I don't fully understand the relationship between the different aspects of light.
• Lumens, I believe is a measurement of the brightness the bulb produces, is this related to power?
• Wavelength, I believe is the color the light is, I.e. Blue is closer to the higher frequency of invisible wavelengths like ultraviolet, and Reds are closer to the invisible infrared wavelengths.
• How do Watts become the baseline measurement for light the plant is bathing in?
I know this is probably some of the most basic things you learn about electricity and light. I apologize if it seems like I could have found this from another source, but turned here for your time. Here are some lights I found around that I think may be used to sufficiently grow plants indoors.
Below Are 3 different lights. The first two are of a 2FT LED, I linked the shot of the specs too. The third is of a bulb from a ballast that holds 2 T8 32W bulbs, 6500K Daylight. Fourth is of ~20ft roll of LED lights, I don't remember where I got these, but theres a small 12V beside each tiny LED; I think it this are waterproof to an extent as well.

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#2
09-18-18, 08:05 AM
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You've asked a lot of questions but I'll cut to the end.

What do you intend to grow? You don't have to be too specific but I just want to know about the plant's light requirements. The roll of LED's you have is mostly useless for growing plants. Some low light varieties and starts can do well with the fluorescent lights. The LED is the most efficient and best suited to a wider variety of plants though it depends on what you are growing.

#3
09-18-18, 08:27 AM
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XXXXXX. In the state I live in it is legal. I sure hope this doesn't stop you from answering any questions I have about light. I just want a full understanding of light, and how it mimics the effects how the sun. Obviously the sun is producing wavelengths of light on either end, far beyond visible spectrum. When I think of it in astrophysical terms it makes sense. Its all radiation. It is many different things, but it is obviouslyvery bright! How can a light that covers a square meter area be as effective for the plant to do photosynthesis?

My broad spectrum of the subject is not on par with what I feel comfortable with buying really expensive lights, without knowing really what I'm looking for. I don't want a guide to say, "this light will do it." "This light won't" I want to be the one making the decisions for my own projects.

Last edited by Pilot Dane; 09-18-18 at 09:46 AM.
#4
09-18-18, 09:17 AM
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- Lumens, I believe is a measurement of the brightness the bulb produces, is this related to power?
- Wavelength, I believe is the color the light is, I.e. Blue is closer to the higher frequency of invisible wavelengths like ultraviolet, and Reds are closer to the invisible infrared wavelengths.
- How do Watts become the baseline measurement for light the plant is bathing in?
It helps to think in terms of sound waves -
Lumens is like decibels, strength of the actual sound
wavelength of red, green, violet is like bass, mid, treble in music.
Watts is the measurement of the total power used, including useful work plus heat.

#5
09-18-18, 10:21 AM
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Thank you for your reply. Although I appreciate a comparison, that does not really answer my questions. Sound waves are audible vibrations of a frequency of energy right? If Lumens are decibels, the its the strength of the light. Wavelength like you said is the variation in frequency, making the light its visible spectrum, different colors. So now how is the measurement of total power not directly related to lumens - heat energy?

If Watts is a measurement of power then:
Watts = Lumens + Heat energy ?

Still how then is Voltage related to watts, and Watts to amperage, and amps to voltage. I think this was hard for me to grasp in physical science in high school, because Ohms is another measurement I remember. idk, maybe I could skype with someone with my questions if I'm too vague or all over the place.

Sorry, I don't want to be a bother on this forum I have never been on it before, I just have questions I really want to learn the concepts, not just memorize what a word that kind of means ::insert whatever::.

#6
09-18-18, 10:49 AM
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You will need considerably more light than anything you have mentioned for most varieties if you want "fruit". The plant you mentioned takes a large amount of light to achieve it's potential.

The LED you listed would be good for sprouting but just doesn't have the power for full plant growth. For most varieties I would be looking an LED of at least 100 watts as a starting point for one plant and you'll probably want more power. If you are getting one light I would get one that's more red and focused on flowering. Vegetative lights are good for growth in the beginning buy you'll really need the vegetative spectrum to get good flowering.

A couple years ago I tried this 45 watt square panel from Amazon. It is good for low light plants and will keep a full sun plant alive through winter but you won't get strong growth or flowering.

I have Kind brand V1 light bars at my office for orchids. They are expensive but very good and their customer service it top notch. I have two 45watt 36" long light bars. One each in veg and flower spectrum. One light bar is enough power for low light plants but even two (90w total) is marginal for full sun type plants partially because they spread the light out so much.

I've had good luck with this light I got from Amazon which is about \$70. It's powerful so it will produce good growth but you'll want to keep an eye on the plants for signs of sunburn in which case move the light further from the plant. It's wicked bright so you don't want it out in a normal room as you'll see stars if you glance straight at it.

#7
09-18-18, 11:02 AM
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To find the actual power pulled by a particular light or device or appliance you can get a "Kill A Watt" (tm) meter that will tell you.

You will have to accept the lumens advertised for a particular lamp (bulb) on its package unless you have a magazine review or word of mouth information to the contrary or you have scientific equipment to make an actual measurement with.

Lumens emitted per watt consumed is much less for incandescent versus other kinds of light which is why those other kinds of light have become so popular.

For LED most of the light is emitted more or less in one direction. For other kinds of lamps the lumens are emitted in several if not all different directions. Then, without good efficient reflectors, most of the light going off in an undesired direction will not hit your plants although those "wasted" lumens may provide accent light (for esthetic purposes) in a room.

Incandescent lamps give off light over a broad band of wavelengths although usually disproportionately less in the ultraviolet region. Fluorescents and LED emit only a few wavelenghs but are generally designed to give off a mixture that looks white to the human eye. A narrow red band and a narrow green band and a narrow blue band will altogether produce light that looks white. Scientific equipment (a spectrum analyzer) is needed to determine whether the mixture given off by LED or fluorescent lamps not advertised as plant grow lights includes enough in the frequency ranges for your plants.

Using your Kill A Watt meter (limited to 120 volts) or a clamp on ammeter or even an ordinary ammeter you can collect together about 12 amperes worth of lights for a 15 amp branch circuit or about 16 amps of lights for a 20 amp branch circuit. Although lighting theoretically allows computing the full 15 or 20- amps respectively, equipment operating continuously for hours and hours should be figured to use no more than 80% of the circuit amperage.

Breakers are rated for both a maximum voltage and a tripping amperage. Usually the rated voltage is 250, so a given breaker could be used either for a 120 volt or (paired) for a 240 volt branch circuit (U.S. systems).

Last edited by AllanJ; 09-18-18 at 11:23 AM.
#8
09-18-18, 12:34 PM
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Originally Posted by Pilot Dane
For most varieties I would be looking an LED of at least 100 watts as a starting point for one plant and you'll probably want more power.
LOTS of light.
Basement growing operations generally require specific high power growlamps.
The heat (wattage) from incandescent or sodium or fluroescent lamps was enough to give rise to court cases about the "expectation of privacy when viewed in infrared". A thermal camera could reliably pick out grow houses by the heat signature.

#9
09-19-18, 08:44 AM
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Thank you all for the information. It has helped.

Now since so many of you seem that what I'm doing is sketchy, could a moderator delete this thread? Lock it or whatever or just delete my posts.

Again, great community, thank you for helping.

#10
09-20-18, 05:36 AM
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It can be very confusing when shopping for grow lights and you need to focus on a few important specs.
Those are color and lumens...... wattage is irrelevant and will vary with the technology you are using.
There are two ideas when selecting lamp color.
To use blue colored light for vegetative growth and red for flowering is one way to go.
The other is to use a single color light in the mid color range like 4100k for both stages.

There is a preference to use two colors but brightness is more important if there is any kind of budget in setting up your lights.
One thing that complicates your choice is that although lumens are important, color specific grow lights can be somewhat lower in lumens output because the color is more specific for growing.

I am working at setting up a small greenhouse for next year and am trying a 4 foot 8 lamp T5 high output fixture.
It is reasonably priced and puts out 40,000 lumens at 4100k.
This fixture does not put out a lot of heat and can be on a pulley system to be adjusted to be just above the plants.

#11
09-20-18, 07:59 AM
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Then I suppose to be even more accurate you need to look at the PAR which measures the amount of light in the spectrum a plant absorbs. Unfortunately unless you are willing to buy or get ahold of the the lights and purchase the testing equipment all you have to rely on is the manufacturer's specifications.

Personally I hate the look of most LED grow lights. The light is a bright pink and plants look almost black. There are some full spectrum LED's coming to market that more closely match the output of metal halide and makes the plants look like plants (ie green).