Alter RGB floodlight?

[ShellNZ]

I purchased an 12v 10w RGB floodlight from here in NZ (theres my first mistake lol).

Turns out I cant control the color, it cycles through 16 colors, one second each.

Took some pics of back and front as Im wondering if its possible to rewire/alter it so I CAN control the color?

Love the yellow cellotape lol

Front of the little PCB board (apparently constant current device)

Back of CCD

Front of floodlight with lid/reflection off (showing led and red wire, assume the black is at the back)

Pink shading is the back of my iphone reflecting color.

As you can see its only 2wire all the way through.

Is there a way?

 

[JPB]

If that LED has four leads there is a possibility that they are R G B and common. If so you could bypass all the controll circuitry and run them from a DC SSR.

It would be interesing to see the back of the board holding the LED and work out if the colour changing is being controlled external to the LED package. If so

 

[David_AVD]

You *could* modify it for discrete RGB control from a DC controller but... (you knew this was coming) you'd need three Constant Current regulator circuits. The effort in doing that wouldn't be worth it imo.

 

[ShellNZ]

Geeeez *sigh* Why do I have to do everything the difficult way.

Thanks guys

Just for information purposes I took a pic of back of led...

 

[Mike]

Its a 12vDC COB LED. I think made by ChiLED by the looks of it.

Most of these 10w modules have a vF figure of 12vDC for Green and Blue and 7vDC for the Red. The large resistor on the front side is to drop the feed voltage to the 7v for the Red colour. its 12 ohm.
Current draw from these chips is 600mA

So you could modify it and use it with a DC controller if need be. You would need to figure out what lead on the chip is +ve (common) then each other lead corresponds with the colours.
You will need to desolder the resistor from the board and solder that in line with the Red lead before hooking it into a 12v source.
The other colours and +ve can be wired straight back to the controller.

Or if you dont want to use a DC controller, use a standard RF controller like this or something similar . but you will still need to solder that resistor into Red lead before connecting.

 

[David_AVD]

The resistor would certainly help with the lower Vf of the red LED. Not sure why they don't have resistors for the other two colours. It could be that they've chosen switching transistors that are somewhat lossy and inherently limit the LED current for blue and green dies.

The problem is that when you wire the LED to an external controller, you actually improve the operation (remove the losses) to the point where the LED will likely draw too much current. That's when they curl up and die.

 

[Mike]

David your right. Technically the Blue and green should have at least a 1 or 2 ohm resistor on it @12vDC just to be on the safe side.

If need be I can try and find the data sheet for this type of LED

In saying this I have 2 running like this at the moment (although its an EDISON chip) direct from a DC controller and they seem fine.

 

[damo1271]

The circuit looks like it uses 3 x mosfets to drive the LEDs. you can tap into the gates on these mosfets and drive the mosfets directly from an external control source. That way you dont need more constant current drivers.
I suspect that the 3 resistors shown as 331x3 will be connected the mosfet gate. Desolder these resistors and connect your control wires. This is easier than trying to lift the gate from the PCB. (I cracked the first one I did and then had to replace the mosfets - that is painful! )
There is another post on this forum that shows the circuit required. I used this in a slightly different chinese RGB flood and it works a treat. I am 99.9% positive you can do the same with your flood.

http://doityourselfchristmas.com/forums/showthread.php?16881-10-Watt-RGB-Flood-Light/page10&highlight=RGB+flood+modify