The eternal light question

[willard3]

Originally Posted by GpsFrontier

. But let say to make the math easy, you have a florescent light that puts out 10,000 lumens at 100 watts. 10,000 divided by 100= 100. Is that 100 kilowatts? Is that per minute, per hour? Also how would you figure out the energy consumption for appliances that don't put out light (lumens)?

If you divide lumens by watts, how would you come out with kilowatts?
Watts/1000 = kilowatts
(Lamp watts/1000) X hours of operation = kilowatt hours
KWH X cost/kwh = cost

[GpsFrontier]

Thanks willard3,
Although I'm simply not sure that the lumens plays a part in the calculation at all. There are many devices that use electricity that don't put out light at all, yet energy consumption for those devices have been able to calculated. If memory serves, the calculations are determined by the watts and amp draw. Also any Resistance (Ohms) will play a part. I don't remember if voltage needs to be figured in, or if higher voltage just helps push through more amps. But bottom line, every cost calculate I have seen relays only on knowing the wattage. So with all that in mind, I just don't think that knowing the lumens plays a part in the calculation at all.

[fuzzygrass]

Your local hydro shop will have a catalog that will have a chart for different size magnetic ballasts. the chart brakes down hours ran and $ per kw giving you a general idea of how much it will cost to run. I know a that a 400w lumatek with a eye super hps will run at 423-425w. I saw that on a different forum

[watercatwn6535nd]

I'm going to go against everthning you may have heard about lights. I ran a test this summer with tomatoes out side and inside with full sun no shade. my inside plants grew twice as big fruited first the out side in natural light.

my bulbs are the cheap $1 at lowes f32 4ft bulbs and my lumens meter reads about 1200 in the center of my light fixture. plants grow fine

to compare i have a system that grows just as well with 1200 watts hps on light rail movers. just cost me more money.

I now believe its the closeness to the light that makes it less money to run. hps put out lots of light but you have to keep it so far away. in florecent the plant can grow right on it.

To much energy being used on heat rather than light out put. and to be fair my 1200 wat hps is in a position of where i run 768 watts of florecents so its a savings of a third. but no light movers, no a/c just fans. its as good and cheaper in the long run.

I now believe and am building a new light fixture for my out door green house that is as simple as one 8 foot florecent bulb mounted right down the center on my grow pot going vertical to the roof and i will be letting the plant envelope the bulb during growth. this way i figure i currently get only part of the bulb shining on the plant so i have to add additional bulbs around it to surround it. now i will have 360 degrees of bulb from one bulb and i belive this will be the same as four bulbs.

with this theory i will go from hps 1200 watts to my current 768 watts to 288 watts. why shine on the plant from the outside when you can go to the center of the plant and shine out all the way around.

[willard3]

Originally Posted by GpsFrontier

Thanks willard3,
Although I'm simply not sure that the lumens plays a part in the calculation at all. There are many devices that use electricity that don't put out light at all,

Isn't this a question on lighting?
If you have lighting, you have lumens
If you have lumens in an electric light, it takes watts to make them.

This is physics and not a matter of opinion.

[GpsFrontier]

Isn't this a question on lighting?

No,
The question is about calculating electricity cost. Just because it's referring to lighting makes no difference. You calculate energy consumption using the same formula whether it's a light, refrigerator, radio, TV, computer, electric fan, pond pump etc. That is not an opinion, they teach Ohm's Law (current (amps), volts and Resistance are the 3 parts of electricity) in school, although it has been a lot of years sense I was in school. Watts is a measurement of the rate of energy conversion, and if I remember correctly is also a measurement of the heat generated by that conversion. No where is lumens (a measure of the power of light perceived by the human eye) mentioned as any measurement (or part of) of electricity.

Once the amount of energy used is determined, then it can be multiplied by the price per Kilowatt that the electric company charges (easily found on your electric bill).

[willard3]

Originally Posted by GpsFrontier

No,
The question is about calculating electricity cost. Just because it's referring to lighting makes no difference. You calculate energy consumption using the same formula whether it's a light, refrigerator, radio, TV, computer, electric fan, pond pump etc. That is not an opinion, they teach Ohm's Law (current (amps), volts and Resistance are the 3 parts of electricity) in school, although it has been a lot of years sense I was in school. Watts is a measurement of the rate of energy conversion, and if I remember correctly is also a measurement of the heat generated by that conversion. No where is lumens (a measure of the power of light perceived by the human eye) mentioned as any measurement (or part of) of electricity.

Once the amount of energy used is determined, then it can be multiplied by the price per Kilowatt that the electric company charges (easily found on your electric bill).

Hence my previous post, ie,

If you divide lumens by watts, how would you come out with kilowatts?
Watts/1000 = kilowatts
(Lamp watts/1000) X hours of operation = kilowatt hours
KWH X cost/kwh = cost

You just don't understand energy very well.

[GpsFrontier]

Originally Posted by willard3

Hence my previous post, ie,

If you divide lumens by watts, how would you come out with kilowatts?
Watts/1000 = kilowatts (not "lumens", unless you are spelling lumens "Watts")
(Lamp watts/1000) X hours of operation = kilowatt hours (no lumens mentioned)
KWH X cost/kwh = cost (again no lumens mentioned)

You just don't understand energy very well.

I understand dividing watts by 1000 to get kilowatts (a kilowatt being one 1000'th of a watt), then multiplying by hours of operation. But nowhere is LUMENS a part of that calculation. Again, energy comes in many forms, and is not the same thing as electricity. Even the wind has energy, or a tornado, even a waterfall has energy, even a fart has energy in the form of methane gas. There are even some farms that are converting the energy trapped in cow farts, into usable energy to power generators. You don't seem to understand the difference between energy and electricity, or you wouldn't keep referring to one when meaning another.

Once again
The form of energy of lumens is "A measure of the power of light PERCEIVED by the human eye"

I'm not sure why it's so important to you that I just believe that a "lamps lumen output" has anything at all to do with calculating its electrical cost. But you also don't seem to understand that the electrical costs of other devices "OTHER THAN LAMPS" need to be calculated also, in order for the electric company to be able to charge for the electricity they use. Fact is lights/lamps are not special, you don't have two electric meters on your house, one for lamps and another for everything else. You can keep trying if it's so important to you (and I won't say never), but good luck convincing me.

[Luches]

One Kilowatt is not a 1000th of a watt but 1Kw=1000 watt. 1 Kw is also what you call 1 unit in the US and at most other parts of the world.

If knowing how much watt a bulb consumes (in Kw/h) and approximately how much lumens it produces, you can in fact calculate both: 1. consumption per hour, day, month etc. and 2. if knowing the surface you need to cover, how many watt per lumens per square ft a specific setup consumes and costs. Yes you can, but you need to know how.

Example with Metal Halide = 70-115 lumens per/watt and assuming that 5000 lumens per/sq ft are appropriate and/or sufficient for the purpose.

Let's assume that one 150 watt Metal Halide bulb would produce (for simplicity as an average from 70-115) 100 lumens per watt and thus producing 15000 lumens. Hence be sufficient for a surface of 3 sq ft. And to cover a surface of 21 sq', you'd need 7 bulbs of 150 Watt, which corresponds to 1050 watt and brings the total consumption of these 7 bulbs close enough to 1 Kw/h.

Making things as even as we can for the sake of simplicity while still keeping the maths accurate enough for the purpose, we can safely say that with 7 MH bulbs, we cover 20 sq ft, produce close to 100.000 lumens and are consuming 1 Kw/h.

Now we can easily and actually put watt in direct relation with lumens or square foot and vis versa and make our own equation for future projections and estimates.

Of course that other premisses and/or choices (of bulbs and lumens per sq ft needed) would also need a different "mathematical spadework", - and most probably not end up in such even numbers! But any 5th grader should be able to take over from here and transfer the described method to another model... without a doubt and without arguing, - right?

[one800fish]

I'm using 6ea 100watt output cfl's in the 6500k spectrum.
6 x 100 = 600watts of light.
These bulbs use 23 watts ea.
23x6= 138 watts.
138watts ./. 120 volts= 1.15 amps.

Same for flowering except bulbs are 2700k.

my utility bill for October was $58.60.

As far as penetration, the blubs are in clamp on shop light fixtures and I can move them where needed and my plants are doing great.

This may not work for everybody but for a $58.60 utility bill, it works for me.

[NorEastFla]

Originally Posted by one800fish

I'm using 6ea 100watt output cfl's in the 6500k spectrum.
6 x 100 = 600watts of light.
These bulbs use 23 watts ea.
23x6= 138 watts.
138watts ./. 120 volts= 1.15 amps.

Just a note about your wattage. The "equivalent" wattage is a "Brightness" perceived by the human eye, and has nothing at all to do with plant usable lumens.

What you have as far as your plants are concerned is 138 watts of total light.

Can you post pics of your plants growing under this amount of light? I'd love to see them.

[NorEastFla]

To expand a little on my last post, a 23 watt CFL has 1,380 total lumens output with a 60 lumens per/watt efficiency.

They also have self-contained ballasts that can, if used in an enclose area, result in quite a heat buildup that could heat the reservoir temperature and/or grow chamber temperatures.

Light-bulb efficiency is measured in terms of lumens per watt—the amount of light produced for each watt of electricity consumed. More lumens per watt means more light for your money.

Incandescent: 10-17 lumens per/watt

Halogen: 10-22 lumens per/watt

White LED: 20-60 lumens per/watt

Mercury Vapor: 25-60 lumens per/watt

Linear Fluorescent: 30-110 lumens per/watt

Compact Fluorescent (CFL): 40-70 lumens per/watt

High Pressure Sodium (HPS): 50-140 lumens per/watt

Metal Halide (MH): 70-115 lumens per/watt

***
Light on a surface (such as a plant canopy) is referred to as illuminance, which is typically represented by footcandles (lumens per square foot, equal to 10.76 lux) or lux (lumens per square meter, equal to 0.092903 footcandles).

Most leafy plants like to have a minimum of 5 thousand lumens per/sq ft of plant canopy. You can get by on 3 thousand per/sq ft, but 5K will make them grow much better and contain much more health giving nutrients and vitamins for your body.

You discover the "Lumens per/sq ft" by adding up the total lumens of your lights and dividing that by the number of square feet of plant canopy you have.

With 6ea, 23 watt CFLs, you have 8,280 total lumens. At the lowest minimum lumens of 3K per/sq ft, that gives you enough light for 2.76 square feet of plant canopy if you expect good growth, short internodal length and average fruiting.

2.7 square feet is the same as an area of 397.44 square inches, or an area about 20 inches by 20 inches.

As you can see, that's not much area. You'll find that HPS is the best all-around lighting for plants indoors. Great spectrum, remote ballasts and a very good lumens per/watt output.

A 150 watt HPS will have about 16,000 total lumens. At 3K per/sq ft, that's enough lumens for an area of 5.33 sq ft or an area of 768 square inches or an area of 28 inches by 28 inches.

An area covered with multiple 150 watt HPS will be much better than an area covered by one larger bulb. The lights can be closer to the plant canopy and each plant receives a much better light and an efficiency of 106.66 lumens per/watt as opposed to the 60 lumens per/watt the 23 watt CFLs will give you. It's a much better bang for your buck.

[halfway]

Awesome post NorEast. I pulled that onto a word doc and saved it for reference.