Powering 12V LED strip with 30V DC power supply

[LiquidMetal]

Hello,

I am looking for ideas what would be the easiest ans safest way to power a 12V LED strip using a 30V DC power supply.

Thanks in advance

[PRR]

Find the current.

Compute a resistor.

If "efficiency" matters, there are more efficient ways. But resistor is easy and cheap, and the watts wasted is unlikely to be huge. (May be a couple of Watts though.)

[Seljer]

Cut the strip into two or three pieces (of equal length) and wire them in series

Slap a big resistor in there, measure how much currents the LEDs draw at 12V, and chose the resistor so it drops 30V down to 12V at that current

Possibly just use PWM to flash the LEDs with a lower duty cycle. Provided the pulse frequency is fast enough (a couple of hundred hertz) only the average current running through the LEDs matters, not the maximum so the LEDs won't burn up

Build a buck converter (look up the LM2576, that'll do roughly what you want providing 3A is enough current)..... or just buy on of these modules off the ebay: http://www.ebay.co.uk/itm/Car-Converter-24V-To-12V-5A-60W-Step-Down-Module-DC-To-DC-Buck-Module-UK-selle-/221451732844?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item338f8d476c (input voltage is listed as 17-35V)

[italianguy63]

+1 on the Buck Converter.  I have used them to convert +12V down to 5V to run USB devices and LEDs in my car.  At $2 or less, they are hard to ignore!

MC