[autojuice]

High! So I would like to build a small LED growlight but I´m unsure how the specs should be calculated and wich would be the best LEDs to pick for my space. I set my eyes on the HomeBox XS so maybe 200w unit would be optimal?? I found this calculator https://metku.net/index.html?sect=vie...calc/index_eng while I was doing some scouting on stuff I need to pick for my solution. I was thinkin of using 27 3w LEDs for my light,21 reds and 6 blue as it would make the R/B ratio 7:2 wich is optimal according to the Internet,true... I don´t know? So both red and blue would need their own string in series,right? Is there something I have overlooked,probably but with your superior knowledge I hope to get some guidance.So no more jibber jabber of my part,let´s design a good quality DIY light. Sorry for my english,please correct my grammar so I can evolve.

[GoeRilla]

First, you need at least twice as many diodes. 3W diodes does not mean that they really use 3W.
Second you ned a constant currant power souce or rather some because they probably can´t give enough power to all the diodes.
Dealextreeme has some that can supply 9-12 3 watts diodes.They are called sku 42906.
They cost 13,44$ each so you can calculate how many you need.
here is a link to some Osram which are some of the best diodes: https://www.ebay.de/itm/25x-Osram-Dra...item2a13f45881

Rilla.

[rives]

Auto, you might want to check out the link in my sig to see how I built my hybrid fixture. It uses @ 180 watts of the Osram LEDs that Rilla linked you to above. You might look at Meanwell drivers, they have an excellent reputation. Heat-sinking/cooling is going to be a real issue at your desired power levels. Do a web search for Knna's tutorials on building LED fixtures - they are excellent and full of great information. He is a frequent poster on here, and is both a wealth of information and very willing to help. Good luck.

[autojuice]

Ok,so we got the LEDS picked out,thanks for the link great find. Is it like 25 of both red and blue or each,was a German site so I dunno? Is the calculator worth anything or should I just stop playing with it? Imma gonna use a heatsink 200mmX300mm and 50mm thick so it is quite massive,would this be enough for say close to 200W? How many LEDs can I fit on the heatsink without going overkill?

[GoeRilla]

Originally Posted by autojuice

Ok,so we got the LEDS picked out,thanks for the link great find. Is it like 25 of both red and blue or each,was a German site so I dunno? Is the calculator worth anything or should I just stop playing with it? Imma gonna use a heatsink 200mmX300mm and 50mm thick so it is quite massive,would this be enough for say close to 200W? How many LEDs can I fit on the heatsink without going overkill?

I´m not sure about how much cooling they need but i know that some people get by with just a sheet of alu with no ribs so i think
you can cool a lot of diodes with that.
The offer from the shop is 25 diodes mixed as you wish.
You shall tell which colour you want in the message box that appear when you pay, i bought 20 red and 5 blue.
The calculator can you forget about, get some swictch mode drivers as i told before.

Rilla.

[grow_right]

why not purchase a lamp? i think there are far to many issues with building your own lamp.

[autojuice]

Originally Posted by grow_right

why not purchase a lamp? i think there are far to many issues with building your own lamp.

Well wheres the fun in that? By building ur own you know exactly how it works and so on in case of failure in the future. I don´t see that many issues with it,LEDs are picked so now I just need to figure out how many I can cram on the heatsink. Then just calculate wich driver and how many I need.And tadaa!... my energy efficient light is ready. I don´t think I will order any components from the states though,so some european links would be nice.

[blimblom]

@grow_right it is also 3 times cheaper for those of us who dont want to break the bank for our hobby.

autojuice, i dont know where you live but maybe you can also check out https://www.cutter.com.au/ which has quite cheap Cree which are one step more efficient from the Dragonplus. check for XPE (royal blue/red) and XPG for white (dont forget to use white to cover those spectrums r/b lack)

also check the specs of each led to calcullate how much current/voltage they need and where they are efficient. For example the dragon plus LED Teile sells are better if you run them at around 500-550mA. They run cooler and more efficient if they put a bit less lumen ..

alouminum profiles work quite well for heatsink. Calculate around 100-150cm2 of total area per watt consumed ( for example a Π aluminum profile of 3x2x2 has 12cm2 of are per cm of lenght)

[autojuice]

Originally Posted by blimblom

autojuice, i dont know where you live but maybe you can also check out https://www.cutter.com.au/ which has quite cheap Cree which are one step more efficient from the Dragonplus. check for XPE (royal blue/red) and XPG for white (dont forget to use white to cover those spectrums r/b lack)

also check the specs of each led to calcullate how much current/voltage they need and where they are efficient. For example the dragon plus LED Teile sells are better if you run them at around 500-550mA. They run cooler and more efficient if they put a bit less lumen ..

alouminum profiles work quite well for heatsink. Calculate around 100-150cm2 of total area per watt consumed ( for example a Π aluminum profile of 3x2x2 has 12cm2 of are per cm of lenght)

Right on blimblom ok so cutter has some mean well drivers wich are supposed to be HQ,now I just need the right spec and the amounts... Let´s do 50 osrams 40 red @550mA and 10 blue@ what?? current... and hope they will run cool on the heatsink cus this math stuff is too hard for my mushy brain. . So all you LED Gurus please come on in and help with the calculations so I can pull the trigger.Need the right model of driver for the reds maybe 2?? and one for the blues. Will see about the whites later. Ok so all I need is the leds,drivers and the heatsink and I´m set ,correct? There will be a thread of construction if I just could get things bought.

[alkalien]

Ok, forward voltages of those Osram LEDs is between 2,4 and 2,8V running at arround 600mA. You get the exact Voltages from the datasheets, there is a graph, Vfw vs. A.

Now add those up for all your LEDs and get yourself a driver with a voltage range your combinded drop voltage fits in. Make sure not to get too close to the edges of that window. Keep in mind, the voltage depends on the current.

actually it is pretty simple once you did a few

I remomend the CEN drivers for multiple strings. Have a look at the new HLGs too. For cheap drivers test the LPFs. For having fun, I recommend the PCB line. Meanwell rocks!

You then need capton tape and a thermal conductive adhesive. We carefully bend the connectors upwards before glueing, it is way easier to solder and the thermal connection between the base and the heatsink is more secure.