Since I wanted spotlights that don't block much daylight and operate safely in a wet environment, I thought it would be a good idea to use ones that are mass produced for cars. So, I bought this:
https://www.amazon.com/dp/B07FR38763...ml_rv0_dp?th=1
One problem, though. "30W" is actually 7 watts because Chinese manufacturers often lie about the wattages of their lights and Amazon reviewers are too dumb to measure the wattage like I did. Anyway, I used them:
The lights are mounted on a wooden board that I normally temporarily put up to brace the polycarbonate sheets for the weight of accumulated snow. You don't see more of these braces because it hasn't snowed, yet. Ha, ha. The lights are connected to a 24VDC power supply that is connected to a photocell that is connected to a timer that is connected to a 120VAC outlet. The photocell turns the lights off when daylight is bright. The timer turns on to mimic the period of light (16 hrs.) during summer solstice where I live.