# RGB Light Fixture power question

#### DrNeutron

##### Just starting in this crazy hobby
Quick question on a makeshift light fixture.
I plan on using some led strip to make a light fixture or my daughter, here are the specs on the strip:
•Working Input Voltage: 12VDC
•Working Current/meter: 0.6A
•Output power: 36W /5 Meter
I plan on using an RF LED RGB controller for control of the light (she can make it whatever color she wants and change intensity, but no way to limit intensity).
The controller is rated for an input of 12-24V DC and outputs 12V with a max of 6A*3 channels. rated output us less than 5A/channel so will keep under that. I am going to use a laptop power supply that is 18V and rated for 6 amps.
Taking this all into consideration, I would guess that 8 meters would be my limit? Or should I go lower in the case using white? I just want to be safe (haven't started designing the fixture yet).
Thanks

#### David_AVD

##### Really old (now a Grandpa)
Community project designer
Generous elf
The controller may accept 12V to 24V, but it will also output the same voltage. You'll need a 12V power supply to use it with 12V lights.

#### DrNeutron

##### Just starting in this crazy hobby
I'll verify that with my meter when I get it Dave (you are probably right, I have a 5A 12V P/S as well).
So do you think I could get away with 8 meters of that strip with a 6A controller or am I pushing it? (if I use the 5 A P/S I would probably drop to 7 meters).

#### ltay13

##### Full time elf
Community project designer
David is right you will need to use your 5A 12v PSU not the laptop one. Seeing as you have 3*6 = 18A capacity with the controller the 5A PSU will be the limiting factor.

I would agree with your idea of only running 7m of the strip using that PSU, especially if it's a Chinese one. 8m is pushing it on white unless it is a good quality PSU.