Hello everyone, this looks like a wonderful forum and I am glad I found it. I would like to build a small LED grow light. I found this previous post on the topic: http://forum.allaboutcircuits.com/showthread.php?t=11687&highlight=led+grow+light
I have built a few decently complex amplifiers and am confident in my skills to actually build the project. My issue is with some of the concepts behind the project. I have the new edition of "Electronics for Dummies" on the way and im sure it will be helpful.
For this project I want to use high powered 1W LEDs. Eventually I plan to try and source parts with the most appropriate wavelengths for plant growth but for now lets assume I will be using a single type of diode; the Luxeon LXHL-MWEC. Spec Sheet: http://www.philipslumileds.com/pdfs/DS23.pdf
The basic specs for this LED are:
Typ. Forward Voltage: 3.42V
Max DC Forward Current: 350mA
Lets say I want to run about 20 of them off of a 12V power supply. If I am understanding thing correctly this is possible by running them is series. Am I correct to think this or do I need a larger power supply?
When I enter these specs into the ledwiz calculator I get a diagram for 7 rows of 3 leds for a total of 21. There is also a warning about the total power dissipated in my resistors. Why is this? It shows all resistors dissipate 7080 mW. Also there are two types used. If I use an input voltage of 18W and 20 LEDs then I dont get a warning and the resistors dissipate 1323 mW. I assume this is a much more sane setup but would like to try understand why this is.
I was reading on insructables about a simple LED driver circuit that powers the exact LED I am thinking about using. Here is the link: http://www.instructables.com/id/Power-LED_s---simplest-light-with-constant-current/
It says that the circuit is more efficient then just resistors and it looks like its possible to drive multiple leds off of the circuit. The diagram on the second page I think shows 3 leds running off of it. If I wanted to use this instead of just resistors would I build one circuit for each row?
Im sure ill have more questions but thats it for now.
Thanks
I have built a few decently complex amplifiers and am confident in my skills to actually build the project. My issue is with some of the concepts behind the project. I have the new edition of "Electronics for Dummies" on the way and im sure it will be helpful.
For this project I want to use high powered 1W LEDs. Eventually I plan to try and source parts with the most appropriate wavelengths for plant growth but for now lets assume I will be using a single type of diode; the Luxeon LXHL-MWEC. Spec Sheet: http://www.philipslumileds.com/pdfs/DS23.pdf
The basic specs for this LED are:
Typ. Forward Voltage: 3.42V
Max DC Forward Current: 350mA
Lets say I want to run about 20 of them off of a 12V power supply. If I am understanding thing correctly this is possible by running them is series. Am I correct to think this or do I need a larger power supply?
When I enter these specs into the ledwiz calculator I get a diagram for 7 rows of 3 leds for a total of 21. There is also a warning about the total power dissipated in my resistors. Why is this? It shows all resistors dissipate 7080 mW. Also there are two types used. If I use an input voltage of 18W and 20 LEDs then I dont get a warning and the resistors dissipate 1323 mW. I assume this is a much more sane setup but would like to try understand why this is.
I was reading on insructables about a simple LED driver circuit that powers the exact LED I am thinking about using. Here is the link: http://www.instructables.com/id/Power-LED_s---simplest-light-with-constant-current/
It says that the circuit is more efficient then just resistors and it looks like its possible to drive multiple leds off of the circuit. The diagram on the second page I think shows 3 leds running off of it. If I wanted to use this instead of just resistors would I build one circuit for each row?
Im sure ill have more questions but thats it for now.
Thanks
Last edited: