I doing an experiment with plants, for which I want to use commercially available LED lamps. They provide the light I need but the area they cover is too small. So I am trying to replicate a lamp of high power LEDs but I have straggle deciphering the necessary power supply, and I wonder if the specifications can be calculated?
The image below is the circuit I want to replicate. There are four arrays of 30 LEDs connected in series (orange outline in image; each LED is claimed to be 10W) and it includes two power supply (based on the image it appears each power supply is 50W). Each power supply feeds two of the four LED arrays (one circuit is shown in red, in the image below).
Using standard values for 10W LEDs: LED forward voltage=3.5v, LED current = 1.05Amps
For the sake of simplicity, I do calculations for each of the two independent circuits (i.e., two LED arrays and one power supply, red outline in the figure). So these are my calculations so far:
Expected voltage driver=Number LEDs * LED Voltage
Expected voltage driver=30*3.5
Expected voltage driver=105v
Expected power driver=Number LEDs * LED Voltage * LED current * Number of LED arrays
Expected power driver= 30*3.5*1.05*2
Expected power driver=220.5W!
Yet the only information in the power supply it says it is 50W. I wonder where my error is? The circuit works, so I wonder if perhaps the LEDs are lower wattage (e.g. 3W instead of 10W) or if this type of circuit uses a PWM so that only some LED's are ON at a given time?.