Trying to build an LED light, please help


by newhavenhydro
Tags: build, light
newhavenhydro
newhavenhydro is offline
#1
Jan23-14, 09:38 PM
P: 2
Hi,

I am new to this site, but it seem like there are some very intelligent people posting on this forum and I was hoping someone could help me out.

I am trying to build a LED light.

I would like to string 10 of these lights together and plug them into the wall.

5 watt
430nm (hyper violet)
6-7 max forward voltage
700mA
1000-1200 mW radiant power (not sure if that matters)

http://www.aliexpress.com/store/prod...447691205.html

I am confused on what parts i need and the logic/science behind how the volts amps and watts work. i am really here to learn i hope someone can help.
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berkeman
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#2
Jan24-14, 04:05 PM
Mentor
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P: 39,628
Quote Quote by newhavenhydro View Post
Hi,

I am new to this site, but it seem like there are some very intelligent people posting on this forum and I was hoping someone could help me out.

I am trying to build a LED light.

I would like to string 10 of these lights together and plug them into the wall.

5 watt
430nm (hyper violet)
6-7 max forward voltage
700mA
1000-1200 mW radiant power (not sure if that matters)

http://www.aliexpress.com/store/prod...447691205.html

I am confused on what parts i need and the logic/science behind how the volts amps and watts work. i am really here to learn i hope someone can help.
Welcome to the PF.

Your question is quite broad, so it is difficult for us to give a simple answer. If you don't yet know basic V=IR type electronics, it will be a big task for us to coach you through this. What background do you have in electronics so far?

From your link: "Voltage: 6.0-7.0V Current: 700mA" -- What are you planning to use for your power source?

Here is a link with basic info about driving LEDs: http://www.ledsmagazine.com/articles...uidelines.html

.
newhavenhydro
newhavenhydro is offline
#3
Jan24-14, 11:16 PM
P: 2
I think i am going to use either a 72 volt 700mA 50 watt driver...if i can find one. or 2 36 volt 700mA 25 watt drivers... and though my prior knowledge is pretty lacking i have been studying up a lot... i understand that volts = amps * resistanse... in my readings i believe i will string negative end of the first star to the driver and the positive end of that same star to the negative end of the next star and so on until the tenth light where the wire from the positive goes back to the driver. then the driver gets spliced directly to a three prong AC adapter....

how does that sound...

berkeman
berkeman is offline
#4
Jan26-14, 02:32 AM
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P: 39,628

Trying to build an LED light, please help


Quote Quote by newhavenhydro View Post
I think i am going to use either a 72 volt 700mA 50 watt driver...if i can find one. or 2 36 volt 700mA 25 watt drivers... and though my prior knowledge is pretty lacking i have been studying up a lot... i understand that volts = amps * resistanse... in my readings i believe i will string negative end of the first star to the driver and the positive end of that same star to the negative end of the next star and so on until the tenth light where the wire from the positive goes back to the driver. then the driver gets spliced directly to a three prong AC adapter....

how does that sound...
Only closely matched LEDs can be driven in series. Do you know if those units are matched well enough that they can be driven in series? It should say on the datasheet, or you can call their technical support folks to ask.

Also, 72V is over what is called SELV (safety extra low voltage). You are getting into dangerous/hazardous voltage ranges there. If you can keep the voltages under 60V, you will generally be in the SELV range. But using more like a 12V power supply and putting the LEDs in parallel with their own individual current limiting resistors would be a much safer way for you to go at this point in your learning...


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