"use a tightly focused LED bar with maybe 6-8 each 10 watters that may cover a 24" X 6" swath"

3 watt LEDs are already past the thermal design of my 2-foot T8 bars. The sheer amount of heat from a 10w LED would require either a VERY LARGE surface area for passive cooling, or active cooling. Active cooling would guarantee a long service life.

Swinging action might be done without power - remember the wind-up baby swings? If we had a mechanism that could keep swinging for 24 hours after a full wind up, no bother with power! Pendulum action is a good idea, but a wider swing will necessitate a longer extension, thus lots of overhead room will be needed.

I've been trying to work on a rotating LED bar for a while, the biggest problem is a reliable slip ring. Good ones will cost almost as much as the LED bar itself, making them prohibitively expensive. The ones in a rotating Christmas tree stand might work, but I'd worry that at that price it would fail prematurely.
khyberkitsune Reviewed by khyberkitsune on . LED bar on a powered pendulum? The biggest drawback to LEDs is still their high cost. The biggest benefits are the long life, the ability to target specific wavelengths, the low relative heat, and - in some cases: to choose or change the viewing angle. I have a 120 watt unit with 1 watt LEDs that does OK for my small 2' X 2' garden, but does not seem to have enough intensity or spectrum without adding CFLs. Looking at 10w LEDs for a DIY light is appealing, but very hard to justify the cost for the LEDs, heatsinks and Rating: 5