mjordan

ok so there is currently another LED topic in the DIY area but i cant get anyone to respond to me so i figured starting a new tread with my Q would help. (based on the fact that my Q isnt lokked at)

the link... LED Conversion

now if i want little less than 3 watts per gallon like 2.8-3 which type of led would i need.

i can calculate it myself i just need to no wat these things are in comparison to a standard/general rule that is comenly used.


http://www.ledsupply.com/07007-pwc-08-3.php
http://www.ledsupply.com/07007-pwc-08-1.php


the links to the 2 different types of led travel supplied me with.^

thanks...

ray_sj

Don't know too much about lighting, but maybe this Wikipedia entry on lumens helps:

"A 23 watt compact fluorescent lamp emits roughly 1500 to 1700 lm, which is comparable to a general-service 100 W incandescent light bulb"

Maybe that gives you an idea how many of those LED units you need? Sounds like it could get expensive, though.

mjordan

to my knowage that doesnt look like it would help. but thanks anyways.

reasons for the leds are because the led may be expensive and to get 3 wats per gallon will be a little pricy around 80 bucks (which is what a smaller compact florecent would cost for about 1/2 the wattage) leds have a life almost 10 times longer for the task trying to be preformed

mathas

Despite lumens not being the best indicator of photosynthetic suitability, that's the best information we have to work with based on the links you provided.

If ray_sj's findings are correct, and a 23W CF bulb emits roughly 1500 lumens, you would need 6-7 of those LEDs to produce the same luminous efficacy. You can extrapolate from there to figure out in general how many you need for the LEDs to appear as bright to you as a standard CF lamp.

I assume since you're trying to reach 3WPG you're trying to light a planted tank. If that is correct, have you given any consideration to the light produced by LEDs and whether or not its even ideal for photosynthesis? You could find yourself spending a lot of money to build a fixture that will last for years but do a sub-par job of encouraging plants to grow.

If you can find a spectral power distribution graph for that LED, it would help.

edit: it looks like there are two links on the pages you posted, one for Endor Star and one for Luxeon Rebel. Are both links applicable to the LED on the page? If so, they aren't horrible for plants. They could be better, but they could be a lot worse.

mjordan

the first link on my first post shows the original posts for TRAVEL who did this same thing for a planted tank

he said to get 5 or 6 of the fixtures but provided me with 2 links. 1 link for a fixture with a high output and another for 1 with only a 1/3 of the power.

my question is which one was he saying 5 or 6 for

Thanks,
mjordan

Tavel

sorry dude, haven't been checking the whole forum.

CFL's have an inflated lumen rating because lumens are adjusted for human sensitivities...human eyes are most sensitive to green, and guess what color florescent emit the most of?

That's right, green.

Guess what color plants don't use for photosynthesis...

That's right, green.

Plants are most absorbent to blue-violet and red, and it just so happens that white LED's have a huge spike in the blue-violet range.

So basically, the lumen ratings help...but they're not a direct conversion.


So onto your project...

Dude, you are sooo lucky you waited! The prices for the high-output tier LED's went way down in price! They used to be $25-$30, but now they're $16!!!

So definitely get the 300lm Endor Star
http://www.ledsupply.com/07007-pwc-10-3.php

three of those (operating at the full 700ma) will be 1,620 lumens, which is roughly equivalent to a 23W CFL...probably a little brighter. Given that, each individual LED is equivalent to about 2.5 watts of fluorescent output...a little more even.

I think you should use better heat sinking too. In addition to the foil, use some 2" squares of 1/8" aluminum stock directly on the LED's. You can get that from the hardware store, no problem.

That should get you on your way, basically 1 LED for every gallon of water. (remember the "3-up" has 3 individual LED's on it).


Also, since white LED's have a weak red spectrum, you might want to add some red LED's to balance it out. (I emphasize the MIGHT because it certainly adds complexity and cost, but may not add that much to the set up).

I'd say get one white LED for every gallon of water, then an additional red LED for every 3 white LED's. That should give you plenty of power and a good spectrum for photosynthesis.

You'll probably have to put the red LED's on some kind of dimmer to balance the light output. You don't want your tank looking all red tinted, lol.

mjordan

thank u so much and i didnt relize the prices went down. thats so cool.

now my Q is wat is a 23watt CFL

Tavel

one of these things...

http://www.lightbulbsdirect.com/page...actFluorescent

mjordan

Thanks

pepetj

mjordan. I saw your first thread and I was into comment on it but so far two things stopped me: 1) I am discouraged to go into LED for plants as yet, cost-efficiency being one of the concerns; 2) I don't fully grasp the way LED illumination works to compare the light emmited by LEDs to the light emmited by CFs, T-8, T-10, T-12s. I try not to provide feedback if I have serious doubts of my understandings of themes.

I am more inclined into exploring the SHO CFs direction and T-2 and T-5s (in theory). I am still using/trying standard CFs T-2CFs, and standard T-8, T-10 and T-12 fluorescent lamps).

I want a PAR meter and a lux meter but they are not a priority right now. Still working on getting a quite complete set of water parameters tests (got a professional dissolved O2, waiting for the dissolved CO2 and the REDOX meter).

Pepe
Santo Domingo

mjordan

if what your saying is corect travel i should need 3-4 of these 3up pods because one 3up pod = a 23watt CFL. but u also say that one led should =1 WPG. based on that i need 10 pods of the 3up. now the more i think about it could the one led = 1 wat per gallon from a stand point of 3 times since i want 3 wpg.

ex: need 90 leds to = 90 gallons

Tavel

i said 1 led = 2.5 watts...so 1 led per gallon of water is in your target range.

3x 3up pods = a 23watt CFL...but just go by the above rule for simplicity.

but yes, you're right. You'd need 90 led's for a 90 gallon tank, which mean 30x 3up pods...that's expensive.

mjordan

what i dont currently understand is how 1 led can equal 2.5 watts.... or 1 watt

and wat about how these powerbrite systems with 4 leds emit 50-60 watts

mathas

Note that the page for the Powerbrite lights you're referring to say "PowerBrite LED Systems use high intensity 1 watt (50-60 lumens/watt) Power LED's" (http://www.current-usa.com/powerbrite.html). That's not saying they emit 50-60W, that's saying each of the four LEDs emits 50-60 lumens per watt of electricity used, which seems a bit low for LEDs to me.

mjordan

OOOOOOO.... i see.

my bad

Tavel

I should be more clear. each LED emits a light intensity that is equivalent to 2.5 watts of fluorescent output.

meaning you'd need a 25 watt fluorescent to emit the same amount of light as 10 LED's

mjordan

and how would i check over your work... 4 eyes are better than 2.

and i just wouldnt mind seeing the jist of it all

Tavel

good idea. I'm going to review it tomorrow.

Just look for lumen estimates on fluorescent lights and compare that to the lumen output of LED's.

mjordan

now a lumen is wat? i know its a rating of light. but can it be directly related to the watts that we need to use to understand the output to watts per gallon.


hope that makes sence

mathas

A lumen is a measurement of light, but as Tavel noted in post #6, it's a measurement of how bright the light appears to human eyes.

There isn't any type of "x watts = y lumens" ratio, because different types of lamps have varying degrees of efficiency, and different bulbs within the various lamp types have varying spectral signatures. Once again referring to Tavel's earlier post, lumens are strongly influenced by the amount of light emitted in the green wavelengths... if you have two bulbs of the same type and wattage, the one with the stronger green output would have a higher lumen rating.

Energystar.gov and Wikipedia both have comparison charts that outline luminous efficacy for various types of lamps that are good for getting a general idea:

http://energystar.custhelp.com/cgi-b...bDj&p_lva=2562
http://en.wikipedia.org/wiki/Luminous_efficacy

mjordan

another words u have to set up a few ratios with the comparing lights

mjordan

just so people know.... i am not buying leds. y---- because i coulnt get the facts,
sorry

Tavel

We gave you so many pages of information here, plus you have the entire internet at your disposal (where do you think I learned it?)...and you think you don't have enough?

What do you want from us? To build it ourselves and ship it to you? There is no instruction manual for this type of project, you just have to figure it out as you go.

mjordan

haha that would be nice.

the good thing about computers are that u can never know the tone that someone is using...
thats y im not going to think your a snob and im glad u tryied to help me but over the course of information i got no sound answer of weather or not i need 5 pods or 20...

no kidding at one point in time it sounded like each led was 5 watts. then it went to just under 2. then to 1.
and finnally i learn there is now realation from lmens to watts so i could be anyones best guess.

im sorry but i am/have order a retrofit kit from ahsupply. i am getting it tomorrow in the mail and im am glad because i am not made of money. the kit comes wit the facts and i went with it.

again im sorry i waisted your time but its been months not only can i not get a reply withing a week of a post but ive been wanting to replant this stupid tank the last 6 months.


EDIT:thanks,
mjordan

Tavel

ok...the kit will eliminate any confusion. That's good.

mjordan

it is up and running as of yesterday...

i love it.
it works well.
i know i made the correct desicion