I've got a 3-9W RGB LED (https://www.adafruit.com/product/2524).
It's connected to a breadboard with a power supply that tests as giving 4.9V and 2A on a short circuit.
I've got 5W resistors at 2ohms for the green and blue leads (the datasheet says they have VF=3.6) and a 3.3ohms for the red lead (VF=2.5V).
The datasheet says the max continuous forward current is 700mA, so I'm trying to get as close to that as possible for each color. According to https://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-led-series-resistor these resistor values should be drawing ~700mA per die on the LED.
But if I hook up the circuit so the common anode lead goes to positive power, then the individual color leads are connected to their resistors, then the resistors go to ground) and put my multimeter in series with the anode, it shows it's only drawing 0.5A. I was expecting a lot more. I want to get this LED really bright. I mean, it's pretty bright as is, but I'm thinking it could be a lot brighter if it were drawing more current.
I'm trying to understand why it's not drawing the full 2A available... In looking at the datasheet again, I'm guessing it has to do with the forward current curves? For example, the red curve shows that at 2.5V it's only going to draw 200mA. Does that mean that if I take my supply voltage of 4.9V and subtract the VF of 2.5V (for red) that I should look on the curve at 2.4V to see how much forward current it will use? If so, does that mean I need to up my power supply from 5V to something higher to get it to draw more current?