Following a two-inch snowfall on Jan. 7, I had cleared our lower 13-panel string with a Mr. Longarm by 9 a.m. Within one hour, it was producing, full tilt -- but the upper string, which I couldn't reach, took several hours longer to shed its snow.

At the risk of turning SolarChargedDriving.Com into SnowOnSolarPanels.Com, here’s a quick update on our ongoing experience and growing expertise with snow covering our 5.59 kW system here in Aurora, Colo.

[In fact, as far as I can tell, no one on the Web is writing as consistently about snow on solar panels as SolarChargedDriving.Com. In that sense, we’re giving you something new, fresh and useful that you can’t get anywhere else!]

Got a two-incher snowstorm Saturday night -- the night before the big Broncos game in which they pulled off an exciting 29-23 upset over Pittsburgh :-) -- and woke up to 15-degree temperatures with perfectly blue skies.

I wrote in my previous entry on snow – an extensive and hopefully useful one in which I put forward 12 different ways to deal with snow on solar panels – that I wanted to try the water hose for the next storm, which turned out to be this storm. Unfortunately, it was too cold Sunday morning to use a water hose.

By 10 a.m., one hour after I'd swept the lower 13-panel string, it was snow free. Notice the upper 13-panel string is still completely snow covered, though.

Mr. Longarm-ed it again
So I used Mr. Longarm to shove the snow off the bottom 13-panel string in our 26-panel system (I cannot reach the upper 13-panel string with a Mr. Longarm, even when standing on a ladder).

By 2:30 p.m. all the snow had melted off both of our 13-panel strings despite temperatures only about 37 degrees. The quick melt came because we had less than 3 inches of snow -- 4 inches or more seems to spell trouble in terms of melting time.

Mr. Longarm is fairly effective, but it’s damn hard work!

An 23-foot extender pole, even one made out of lightweight materials, forces you to work your muscles, especially the forearm and trapezius muscles a lot. There’s also the small risk of scratching the panels, though Mr. Longarm’s plastic extender rings tend to hit the panels, not the aluminum pole itself, partly because I’m very careful, and partly because they stick out more.

On Sunday morning, I was guessing that our lower 13-panel string, which I cleared by 9 a.m. would be completely snow/ice free by noon on what was a cold but totally blue sky Colorado day. I also predicted that the snow on the upper 13-panel string wouldn't melt much and that we'd lose an entire blue sky day’s production from it.

2 inches or less melt quickly
Turns out that I was wrong about the sun's capacity to melt snow off our panels.

It was strong enough to melt the snow off of our upper 13-panel string by Sunday afternoon. However, it took about four hours from the time the sun first hit the string to when it began producing electricity.

Meanwhile, the 13-panel string I was able to clear of snow with the Mr. Longarm by 9 a.m. started producing, full tilt by 10 a.m., at least two to three hours before the upper string. 

The moral of the story: There seems to be a critical mass in terms of snow amount. Two inches and under, and the sun appears to be able to penetrate enough through the snow to fairly quickly heat up the panels and the snow comes off within a few hours in blue-sky conditions and temperatures around 32 degrees Fahrenheit. At three inches, or perhaps four inches or more, the sun can't penetrate to create this effect and it takes a long time -- sometimes days -- of sunny, blue-sky, but also cold weather for the snow to finally melt off the panels on its own.

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