Even what's billed as the world's largest lemon battery can only generate enough juice to charge a small battery cell, so Mark Rober tries a few other fun power generators with a bunch of young scientists-to-be. Read the rest
We live on a street with no streetlights and it gets very dark at night. People who come to our house at night have trouble seeing things. I bought one of these $(removed) solar powered motion sensor lights with a 20-LED array and PIR (passive infrared) motion sensor and mounted (hardware included) it on a 12-foot wood column at the far end of the driveway. Lucky for me, the solar panel is facing the south so the batteries get a good dose of juice every day.
It works really well. When a car or person enters the driveway at night, the light comes on and throws surprisingly wide coverage. The light is so bright that it hurts to look directly at the lED array. The back of the unit has a 3-mode switch. You can set it to turn on and stay on when it gets dark (in one of two brightness levels) or to turn on only when it detects motion (the setting I use). People on Amazon say the batteries run down in 11 hours if you set it on the dim mode, and 2 hours in bright mode.
Solyndra, a would-be solar energy manufacturer that went belly up, has been in the news a lot lately because, before the company failed, the United States government gave it a sweet financing deal.
While there are some good questions to be asked about the way the financing for Solyndra was handled, the failure of this one company shouldn't really be extrapolated into a referendum on government loans for energy projects (which have otherwise been pretty successful) or the potential of solar energy. But that's not really the interesting part to me, anyway.
The interesting part is what David Biello, of Scientific American, talks about in a new article on what actually made Solyndra different and what its failure tells us about trends within the solar industry. While most solar panels are flat expanses of silicon, Solyndra was creating tubes lined with a semi-conducting material. The idea had promise ... and risk, Biello writes:
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On roofs that didn't line up with the sun's path across the sky, the cylindrical nature of the solar module allowed owners to get more power off the roof by capturing diffuse or reflected light. The panels did not require heavy racks that anchored deep in the roof for support but rather lay flat and spaced out to allow wind to flow through them, allowing them to withstand gusts up to 210 kilometers per hour as demonstrated during a test installation in Florida that survived a tropical storm. That also allowed more of the panels to fit on any given roof.