Last week, I installed a dozen solar-powered LED walkway lamps in my front yard; one of several small DIY projects I have undertaken to adapt my home in a sustainable way to my family’s habits. The details of how these lights work are described in my recent post, “Solar LED Luminaires Light My Path Home”, but I have not had a chance to check on their performance until this evening.
I took a picture of my walkway after sunset to show the level of illumination these solar LED lamps provide. I intentionally used my neighbor’s front yard as a backdrop in the photograph because his yard is lit by conventional, wired, incandescent walkway lamps.
The lights in the foreground illuminating the ‘S’ shaped walkway are my solar LEDs, and the line of lights near the top of the photo are my neighbor’s conventional outdoor lamps. My neighbor’s lamps are across the street and thus are farther away than the LEDs, but his conventional lights still appear brighter. Plus, his incandescent bulbs glow with a warmer hue than my LEDs, which have a starker, artificial white tone. Nonetheless, the solar LEDs do their job well, lighting the walkway leading to the front of my house. Plus they don’t add to my electricity bill, and the bulbs should last many, many years. So, I am content with their lighting performance.
The energy storage and utilization efficacy of the solar LEDs is determined by the ratio of how long they have charged compared to how long they stay lit. According to gaisma.com, the duration between sunrise and sunset yesterday at my locale was 13 hours and 27 minutes, with sunset coming at 8:14 pm. I took the following picture at 2:44 am this morning, by which time, the solar-powered LED had been continuously running in darkness for about 6.5 hours without any signs of degrading illumination intensity.
Of course, the real test will come in December on the Winter Solstice, the shortest day of the year. Will these lamps stay lit all night with only a little more than 10 hours of sunlight? Also, given my southern latitude with respect to most of the rest of the country (roughly 33° 13′ North), the performance I report for these lamps is not representative of their ability to stay lit in more northerly (or less sunny) locals like Minnesota, Maine, Washington, or Alaska.
By the way, my neighbors across the street turned off their conventional walkway lights just after 10:00 pm, presumably to save electricity.