how many 10w leds

[canadianbudz604]

Originally Posted by mike31154

Need to know what your CPU power supply is rated at & what the voltage output is. Simple math using Ohm's Law after that. If your power supply produces 50 watts, you could run about 3 to 4 of the 10 watt LEDs on it. Best to have about a 25% safety margin there. If you hook up 5 of these LEDs to a 50 watt power supply & run them at 100%, the power supply won't last long & you'll be risking some fireworks.

How do you intend to limit or control the current to your LEDs? Are you looking to hook them up in series or parallel? I use standard 12 volt power supplies to run my build (parallel), but also have dimmers in line to keep the voltage at safe levels. Different colour LEDs will have a different maximum Vf (forward voltage). Royal Blues usually take a lower Vf & run at less current than the 20000K LED. Exceeding max Vf will cook them in short order.

I'm going to hook them up in parallel, I could use dimmers, but I don't intend to use any whites. My tank Is a 40g breeder with a 90w led fixture already. (This is a dimmable fixture) with 15 6500k Cree and 15 blue Cree. Could I use resistors? Or should I just dim them?