hooking up 3 watt LEDS

[Cyparagon]

Interesting... Is your power source rated for 10A?

You might be better off running three in series and calculating your own resistance values. It would result in less heat and greater efficiency.

 

[LarryDFW]

Mohrenberg;

I've made quite a few AC powered lights out of 3 Watt Cree's.

The resistors are just lowering the efficiency, so you need to eliminate them.

For large arrays, I usually go for 24 VDC to power them (laptop supply).

You can run about 6 in series with 24 VDC ( or 12 @ 48 VDC).

One resistor may be required to limit current of the string to 700ma (for heat).

They will make a very efficient light source.

This is a 9-watt model I made from a switching power supply:
http://www.candlepowerforums.com/vb/showthread.php?t=171588
It replaced a 13 watt compact fluorescent with better color and more light.

LarryDFW

 

[FireMyLaser]

Either you don't have enough power, or you forgot about the polarity.