PDA

View Full Version : 3w Red led`s


felps
09-30-2011, 12:26 PM
I received some 3w red led`s today (typ 2.2v,750mA) ,wired them up to a driver (680mA).
When switched on they contiuously flash on and off,which seems like a constant rate, does anyone have any idea whats at fault,i.e. led`s,driver or my soldering ?

Thanks
kerry
09-30-2011, 12:41 PM
Did you get the driver from ebay? topledlights? My driver did the same thing!!! He tried to say I hooked them up wrong, I put it in the mail today.
felps
09-30-2011, 01:08 PM
LED-DNA
kerry
09-30-2011, 01:54 PM
I think they had some of the same brand, mine was red. Either way, I am using a 12V 500ma wall wart for the time being. I think I am going to order one from rapidled.com .
kotlec
10-01-2011, 09:28 AM
Usually driver does that when voltage is too low or too high to drive leds. I mean too many or too few leds as per specification.
rygh
10-01-2011, 02:00 PM
Usually driver does that when voltage is too low or too high to drive leds. I mean too many or too few leds as per specification.
+1
What are the specs? We can probably help.
felps
10-01-2011, 02:14 PM
I guess the spec`s of driver or led`s are wrong then,I placed a resistor inline with output for a few seconds and they stopped on.
felps
10-01-2011, 02:21 PM
Running 10 led`s


http://www.ebay.com/itm/ws/eBayISAPI.dl ... AQ:US:1123 (http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&item=220760727318&ssPageName=ADME:X:AAQ:US:1123)

http://www.ebay.com/itm/3W-RED-80lm-650 ... 33697be9ba (http://www.ebay.com/itm/3W-RED-80lm-650nm-660nm-LED-Plant-Glow-Light-/220813060538?pt=LH_DefaultDomain_0&hash=item33697be9ba)
rygh
10-01-2011, 09:28 PM
That driver is rated 20V to 36V on the output.
Dc forward voltage on the LEDs is rated 2.2V to 2.4V.

Minumum LEDs:
20V / 2.2V = 9 LEDs.

Maximum LEDs:
36V / 2.4V = 15 LEDs.

Those are theoretical. My guess is more like 7-16 would be fine.

Alternately, you can put a resistor inline as it sounds like you did.
But make sure it is pretty high power.
felps
10-02-2011, 01:46 AM
I checked the voltage drop across array and diodes,its running at 18v and 1.8v per diode so I`m going to add more led`s to take it over the drivers 20v minimum.
Adding a couple more led`s wont do my total wattage any harm :roll:

Thanks for running through it with me
felps
10-02-2011, 04:49 AM
Two more added now running at 2 volt per led and working fine