Success! (sort of). I connected my lights to a laboratory DC power supply and they started to light up at about 18 Volts, with full brightness at 24 Volts. At that voltage, they were drawing 1.5 Amperes, so a total of 36 Watts, which is what was marked on the unit. I now have the problem of getting a suitable power supply I went to HD, Radio Shack, and two electrical supply houses. None had a 24 volt DC power supply, although one of the supply houses showed me a WAC power supply which they said would work. It was labeled 24V AC, but the counter salesman said "it was AC-DC", which I don't believe. However, will LEDs work on AC?

I have integrated LED exterior lights from Hinkley. They work great. One did fail, and despite being outside of warranty they shipped a new LED module and driver no questions asked. It was annoying to replace but not especially difficult.

If you look closely at the photos of the fixtures, you will see that the Nora Cobalt is a "retrofit" type fixture (like the Halo the OP originally asked about) where the driver, heatsink and LED board are in one compact "trim" unit that is installed in a standard metal housing used for various kinds of fixtures. If the fixture fails, the "trim" unit would need to be replaced. The Lightolier LyteCaster L3 is a modular design with the driver (step-down transformer and current stabilizer) mounted in the housing and the light unit and heat sink fits into the "trim". If the fixture fails or the color dims, the appropriate part can be replaced. The parts can also be upgraded. These fixtures need a more substantial heat sink because the COB chips are more compact than the typical SMD chips. The Nora Cobalt is intended for residential use and the Lightolier LyteCaster L3 is intended for residential and light commercial use. I recommended them because they are both more powerful than typical LED recessed fixtures, are more deeply recessed, have an adjustable beam angle and use a superior COB LED. The L3 also has a great wall-washer for a more uniform light on a wall but it costs another $20+. There are no bargains in good lighting.

Thanks, Bill! I couldn't resist responding to Mike. It brought back memories of growing orchids in the frigid NE for over 20 yrs. It wasn't just the shorter daylight hours, but the cloudy, grey skies and trying to flower orchids in NY in the old days when LED's were not around. I had tried regular light bulbs but they gave off too much heat and you couldn't put them close to the plants. My octopus lamps worked. I had so many. When Target or Home Depot had a sale, I'd run in and buy some more. But, I did have a large house with floor to ceiling windows so it was a bright room when the sun was out. Mike, I'm really tossing the idea of moving back. I'm so unhappy now with a number of personal issues, I realize I'd like to be closer to family and old friends. But I'm not doing anything in haste. I'll give it a year or so. Yes, Florida is like a orchid growers dream. So easy to grow them here. Heat, humidity (did I mention I used to run humidifiers blowing steam on my orchids in NY??). Humidity is off the wall here. However, because of such constant humidity, you run into fungal issues. That is something I'm not good with. Also, the water is not good. I've had RO tank installed and put numerous rain barrels on every gutter. I think no matter where you live and grow, you need to understand what you are growing and try to do the best you can to adapt your environment to meet the challenge. There are certain plants, both dirt plants and orchids which don't do well in your environment. So rather than drive yourself crazy, you find the plants you can work with. The challenge is fun. Jane