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Topic: LED driver shield (Read 2 times) previous topic - next topic

redtop03

sorry guys,I didn't really know what I was doing or how to ask for help,the LEDs that I plan to use are Bridgelux

royal blue
Wavelength: 452-455nm
Forward voltage: 3.6V @700mA
Radiant flux: 360-380mW @ 350mA
Max. current: 700mA

white
Color temperature: 6500-7000K
Forward voltage: 3.7V @700mA
Lumens: 180-200 lm
Max. current: 700mA

I thought these were 3v each,I see now that I can only use 6 per driver channel,and I plan to connect the LEDs in series.....

from what I've read about some LED drivers,I assumed that if you have a driver that ran at 1000ma you could connect 2 strings of 500ma LEDs and it would split the 1000ma current between the 2 strings....

I've never did anything with LEDs before so I'm still trying to learn...I don't think this driver shield is gonna be enough for my needs,looks like 36 LEDs will be the max I could use without stacking about 4 of those shields...I appreciate the help

Willie McDaries

Chagrin

This was just asked about 2 days ago: http://arduino.cc/forum/index.php/topic,161849.0.html

This is a buck driver so input voltage must be greater than the forward voltage of the LEDs.

The maximum current through each driver is determined by a sense resistor. They appear to have solder jumpers to enable different combinations of resistors that are already present on the board.

You can't have strings of LEDs in parallel connected to this or any driver; they will not balance current. Each string must be individually current limited.

One string of 8 * 3W LEDs at 500ma suggests individual LEDs with a forward voltage of 6 volts, and 8 LEDs in series would be 48V. That's greater than your 24V supply and over the 30V limit of the driver. You should also post a link to the LEDs you're using for more accurate advice on what would be possible.

muddy

Do you have 8 separate leds? Or 8 connected in series?

Do you have more specifications on these leds? Like voltage? I assume the current per led is 1A (since it's 3W).

You can not connect 2 strings to 1 channel.

redtop03

I'm still in the planning stages of building an aquarium controller using the Arduino Mega 2560....

I have a few questions about this shield...and if this has already been ask here,forgive me,I'm new here and extremely lost so go easy on me please :D



http://www.ledsee.com/index.php/new-products/arduino-6-channel-led-shield-035-07-1a-detail

I plan to use an external 24v 15a 350w power supply to power the LEDs...

can this be used with a series of 8 x 3w high power LEDs ?

according to the specs for the shield,current is selectable between 0.35a , 0.7a , and 1amp...

if I use 500ma LEDs,can I add 2 strings of 8 x 3w LEDs per channel providing I don't exceed the amperage of the 24v power supply ?
Willie McDaries

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