input output power

[BaronS]

Is the power quoted on a lamp the input (how much it drains) or output (how much it throws) power?

 

NOTE: my Nelson 48W CFLs quote an output equivalent to 200W (240? threw box away) incandescent. Forget about the comparative output for a moment, does such a lamp draw 48W of power?

 

Does a 250 HPS draw 250W?

Another way of asking would be: Is the output power of a 600MH 600W? and if so then what is it's power input (drain)?

 

_IF_ the number is an indicator of output power then the input power is 'rating' (eg 48W) + losses.

_IF_ it's input power then output is rating - losses.

 

My little Nelsons are doing OK for the 18/6, the young ladies under them appear to be growing with quite short internodal distance, but I'm pretty sure I'm going to want to run a separate box as 12/12 and might want another lamp in the 18/6.

 

I'm wondering about the different efficiencies of lamps and my overall power use. I can see 4 or 5 CFL in the 12/12, or maybe a single 250 HPS.

[SukonmiSkunk]

most ballasts will have an amperage rating.. this is what you should be looking at for power draw

a 2.5mm power circuit will allow around 28-30 amps of draw.. MAX.. youll get a little more ..like 32 amps.. but i would always leave a little in spare.. any more and you will me melting wires...

 

my 600watt digi ballast draws some where around 1 amps on start up.. and runs at around 2-3 amps.. so check your ballast box.. and ad up how many amps it draws... to figure out how much you can run off one circuit...

 

theres a few sparky's around that can answer in more detail.. but if you stick with these basics you should be ok..

[nitram]

Hi BaronS ,

aye - stick to what basics you need to know otherwise do a electronics course otherwise you will end up chasing your but.

 

If you do go searching understand the difference of an "amp" & "watt" that will be the only basics you need to know.

 

You can buy "plug & play" gear all you need to do is 'go' .......'do it'

Nitty.

[chuffer]

Hopefully this should answer your question, its the first time I've tried quoting so I hope it links ok. The second paragraph explains how a 1000w bulb wont necessarily draw 1000w as it also depends upon voltage (and some other details).

Last para shows how you can still get a good idea what your system is going to draw, if you can be bothered with the mucking around.

https://cannabis.community.forums.ozstoners...mp;#entry231041

Cheers

Peace

[BaronS]

DOH! Ya know, if you look closely at a Nelson 48W CFL base it actually states .30A.

 

P=IE, = .30*240= 72W

 

so it would seem that Nelson 48W CFL's draw 72W. ( I wonder if that's a max, it also states 220-240, .3 at 220 would be 66W)

 

Not very efficient, 67-73%.

 

That 600W digi-ballast is running anywhere from 480-720W, worst case is 83% efficiency but I doubt it's doing 125%.

 

Of course, the figures could be wildly conservative. It's not uncommon for electrical gear that draws ~0.2A to be rated 0.3A.

 

I think I need that current meter. I know the house voltage is stable (most of the time), Uninterruptable Power Supply on my 'puter logs incoming voltage. Maybe I should just connect the lamps to the UPS, see how the load varies.

[bullseye]

yeah it's rating is 'power consumed'.

you don't have the right idea with input and output power, that's more for a motor, if we were talking in terms of output for a light it's energy is measured in lumens. the electricity it needs to produce lumens is measured in watts.

the basics of watts is voltage x amps.

don't be concerned with what it's actually using because with our alternating current system we have a constant change in voltage.

the losses you are speaking of don't come in terms of watts - the losses in a light come mainly from heat. they're different energies.

so it's not input or output it's just consumed and it's not 100% accurate, it also fluctuates 50 times per second, but the average power consumed is 48W for your CFL's. = 48W per hour.

[BaronS]

GRRRR, that was no fun at all. Ran a lead from the UPS to the grow. The variation, second to second, in what the computers drag from the 1500VA UPS is larger than the additional drain from 2*48W Nelsons.

[BaronS]

well, 48 watt hours per hour. If it's the true power consumption that is quoted.

[bullseye]

it's always the true power that's quoted.

the reason it's 48W is because we use the equation P = V x I x cos (theta).

and the reason it's not so straight forward as P = V x I is because these fluorescents and our ballasts use inductors which throw the current out of phase with the voltage.

[BaronS]

OK, so we're getting close to certain that the quoted value is (phase corrected) power consumption (and probably should be quoted in VA, but there's only a few who actually know what that means, let alone why).

 

Now, do 5*48W Nelson CFLs put out the equivalent lumens to one 250W HPS? but it's actually a bit more complicated than that too, they gotta be the right frequency lumens.

 

Unless anyone has hard evidence to the contrary though I think my original question is answered. In general the rated wattage of a light fixture will be the consumed power. Don't try to run more than 4*600s off a single power point but 4*600 should be safe (the equivalent of one of those hunking great 2400W radiators). You also need to consider there are other items on the circuit, heat your dinner in the microwave and your lights may go out.