I'm putting together a custom aquarium lamp as a hobby project and I'm not sure of the best way to configure the LEDs.
All the LEDs are Cree and I am looking to push ~800ma through them.
5x whites with a forward voltage of 3.4v (XTEAWT-00-0000-000000H51)
2x blues with a forward voltage of 3.4v (XTEARY-02-0000-000000Q04)
3x reds with a forward voltage of 2.1v (XPERED-L1-0000-00801)
I am not sure whether to go with a dedicated LED driver or a standard 12v strip supply. I would prefer a 12v supply as they are available locally.
I figured to run with 12v:
3.4v - 3.4v - 3.4v - 2.20hm 5W resistor = 818ma, 1.5w in the resistor.
parallel
3.4v - 3.4v - 3.4v - 2.20hm 5W resistor = 818ma, 1.5w in the resistor.
parallel
2.1 - 2.1 - 2.1 - 3.4 - 2.7ohm 5W resistor = 851ma, 1.8w in the resistor.
I am concerned about the power dissipation in the resistor being high and adding to the thermal load.
Is there a better way to go about this? I looked for 'dual channel' LED drivers so I could hook up two strings of 3.4v and 2.1v but they don't seem to exist.
I considered using two 800ma drivers into one series line of 3.4v and one series line of 2.1v but that seems ugly.
I looked into some preassembled aquarium lamps and they seem to use SMD resistors only, so there must be a trick I am missing.