DIY Led Wiring Question

[Hishman]

Hello,

 

I have a marine orbit led 24" and I managed to fry the controller since it got wet. So now I run it off an outlet timer and have hardwired the blue channel. Below is what the wiring looks like for the blue channel to run at 100%. The driver for the marine orbit is 12v and 4A so only ~23 watts of its capable 48 watts are being used. I plan on adding a couple strips of leds to the underside. I was going to experiment with ohm resistors inline on each channel until the get the desired look and par. Am I on the right track here?

 

Photo below for questions and confirmation on wires. When I touch the 4th wire to a running +/- led channel the light goes off. I can't figure out what this 4th wire is for. 7.5 volts run from the + wires to the - ground. 12v runs runs from the wire in question to the ground with a 10,000 ohm resistor. When the wire in question runs directly to the ground, it jumps voltage for a split second before a short protection circuit kicks in. 

 

Running the wire in question to a positive post on an led, and the ground to the - lights up the led. Is this just an unregulated 12v 4A circuit?

 

 

 

 

[Hishman]

Bump!

 

Some more info. Orbit marine LED only draws about HALF of what its advertised for 😲

 

My plan is to run a buckpuck inline this 12v wire and run as many 1W led's down the length of the orbit until i reach the PSU watt limit.

[mcarroll]

Can't remember for sure about Current, but some vendors advertise the nominal wattage of the LED's in use and some advertise the actual wattage.   IIRC, very few vendors report actual.

 

A 165w black box does not use 165 watts during usage, for example....it's just an indicator that the unit has 55 three-watt LED's.

 

Not sure what LED's are on the unit you're looking at, but it's common for some types of LED's to be run at 1/2 to 2/3 max wattage for maximum life / to avoid prematurely setting the LED's on fire.  😉

[Hishman]

Thanks for the response!

[blasterman]

Most Chinese LEDs are using 3volt forward voltage tech now, so it's quite possible it's running 4 LEDs in series off unregulated 12volts. Older LEDs are running 3.6-3.7 volts. That big resistor kinda points that way.

 

My Mars Aqua would melt if driven at 165 watts. 🙂  The things have like 8x10 inches of 1/10 inch aluminum PCB as a heat sink.

 

Chinese 3watt reef LEDs rarely run more than 700mA....which if you do the math with 3-3.1 forward volts doesn't equal 3 watts, but who you gonna sue?