we calculate the consumption of the led light.
The image shows the working point of an LED (extract from Cree XP-G led datasheet). Each LED is powered by a constant current of 700mA. With this current, the voltage across an LED is equal (approximately) to 3.2 Volt.
The power consumed by each LED is given by:
P = I(current) x V(voltage) = 0.7(Ampere) x 3.2(Volt) = 2.24 Watt
The total power consumed by light is only: Ptot = P x num.leds = 2.24 x 5 = 11.5 Watt
So it is you who I "copied" the supporting of my diy led fixture from. That was almost a year ago and I saw a post similar like this but in an italian forum although I don't understand italian (I hope that's you ^^). Thank you for sharing your tank and your lighting fixture.