Sun hours

[DanS26]

When the panels are clear, are you getting full power from the array ? Got to be some reason half the panels didn't clear.

Just looking again at the pic....it appears to me that there is a slight offset between building sections...maybe 6 to 12 inches. This offset may be enough to create a wind eddy that built up a drift on the covered panels. A deeper snow mass could cause the slower melt. Just guessing though.

[Mike90250]

When the panels are clear, are you getting full power from the array ? Got to be some reason half the panels didn't clear.

[SunEagle]

Victory!

For now. I would hate for Burningislove to have to wait until Spring to get any future snow off the panels.

[DanKegel]

Victory!

[Burningislove]

Turn up the heat in the other part of the house (the part with the insulated ceiling) ?

Are the 2 arrays on 2 inverters ? Maybe 1 inverter shut down and is not working ?

Both sides have very good, modern insulation in the attic floors (ceiling of the livable house). So cranking up the heat wouldnt do much as it wouldnt reach the attic. The house is already quite warm due to the wood stove that heats the whole house, including keeping the hobby room above the garage at a comfy 60 degrees in the winter.

The two arrays are fed into a common inverter (Solar Edge), but are run separately and then joined in the inverter box. It's been producing some power, but of course not that much given it's winter and one half of the array is covered with snow.

I took the advice and used a snow rake to carefully remove the snow dam from the edge of the roof up to about a foot away from the lowest panels. It seemed to work well as there was just an avalanche and the covered array is now about 50% clear and the rest should fall off in today's warm, overcast weather and tomorrow sunny, colder weather.

[Mike90250]

Turn up the heat in the other part of the house (the part with the insulated ceiling) ?

Are the 2 arrays on 2 inverters ? Maybe 1 inverter shut down and is not working ?

[Burningislove]

Do you have pictures? The installer leaves experience to show all that can go wrong. My feeling is that with limited
options, a roof mount system is pretty much SOL in snow.

Yes, see attached. Also started a new thread to not (further) distract this one that has more details on the system, roof, house, etc.

https://www.solarpaneltalk.com/forum/solar/the-pros-and-cons-of-solar-energy/304077-ice-dam-forming-but-only-on-half-the-array-help-needed

[bcroe]

Any recommendations for when it DOESNT naturally slide off? My installer said the same thing, not to worry about it and that gravity will take care of this as my roof is well pitched. Reality is that half of my array cleaned itself, the other is completely covered in snow and has a huge snow/ice dam at the bottom that will prevent anything from sliding off. Both halves of my total array are identical and face the same direction with same roof pitch. Unclear why one side is fine, the other is a disaster.

Looking for ideas how to fix this mess. It's a colonial house so the roof is high up and I can't get a ladder up there this time of year with all the snow. Hesitant to use a roof rake for fear of damaging the panels.

Do you have pictures? The installer leaves experience to show all that can go wrong. My feeling is that with limited
options, a roof mount system is pretty much SOL in snow. If panels are 2 high, the snow will have to slide twice as
far to clear; unless there is a big gap between upper & lower panels. Even a ground mount can have problems with
snow build up at the bottom. Here a 2' gap between panels and the ground is marginal; 3' would not build up to
obstructing sun so fast. Guess that could be done on a roof; haven't seen it yet.

Assuming the snow has a place to go, there will be motorized vibrators attempting to shake it off on the next round.
Bruce Roe

[J.P.M.]

Any recommendations for when it DOESNT naturally slide off? My installer said the same thing, not to worry about it and that gravity will take care of this as my roof is well pitched. Reality is that half of my array cleaned itself, the other is completely covered in snow and has a huge snow/ice dam at the bottom that will prevent anything from sliding off. Both halves of my total array are identical and face the same direction with same roof pitch. Unclear why one side is fine, the other is a disaster.

Looking for ideas how to fix this mess. It's a colonial house so the roof is high up and I can't get a ladder up there this time of year with all the snow. Hesitant to use a roof rake for fear of damaging the panels.

To be clear, I never wrote, and do not mean to suggest not being aware of possible dangers.

Might be that wind patterns are slightly different and there is some drift buildup on the covered array that doesn't manifest itself under prevailing wind patterns. Might be that the clear portions of the array run warmer than the other portions and melt snow quicker, and run warm enough to refreeze the melt and disallow ice damming. Might be a different response to variable freeze/thaw cycles. When it comes to weather, you can pretty much bet that whatever happens will be the result of several things and may or may not happen the same way every time.

[Burningislove]

Maybe yes, maybe no. It depends. sometimes snow will slide of, sometimes not. Beware of snow slides.

Any recommendations for when it DOESNT naturally slide off? My installer said the same thing, not to worry about it and that gravity will take care of this as my roof is well pitched. Reality is that half of my array cleaned itself, the other is completely covered in snow and has a huge snow/ice dam at the bottom that will prevent anything from sliding off. Both halves of my total array are identical and face the same direction with same roof pitch. Unclear why one side is fine, the other is a disaster.

Looking for ideas how to fix this mess. It's a colonial house so the roof is high up and I can't get a ladder up there this time of year with all the snow. Hesitant to use a roof rake for fear of damaging the panels.

[bcroe]

Looks like dreary Dec is past, getting more more sunny days where production reaches half the summer peak.
1/2" snow came at night; I looked at the gloom and said "is it worth cleaning them?". A little later though the sun
started showing, so I went out and cleaned them up. The inverters immediately showed 12 KW. Once the sun
cleared all shading, they maxed out at 15KW whenever no cloud was blocking. Its often too cold for the heat
pump, but I'm trying to keep enough resistance heat on so that the furnace doesn't run. Bruce Roe

[SunEagle]

It was a little late, but eventually the sun come out on one of the shortest days of the year and made me 70 KWH. Bruce Roe

Every little bit helps. I hope you don't get as much bad weather as you did last winter.

[bcroe]

It was a little late, but eventually the sun come out on one of the shortest days of the year and made me 70 KWH. Bruce Roe

[bcroe]

It is standard procedure in snow country to put panels in landscape orientation, but not for the reason you mention. Within most solar panels are several strings of cells in parallel. The strings run vertically if the panel is in portrait orientation and horizontally if the panel is in landscape orientation.

Snow slides down the panel and gets caught up on the lower frame of the panel. In portrait orientation, the snow blocks the lower part of each string of cells within the panel (no power). In landscape orientation, the snow entirely blocks just one string of cells and leaves the other parallel strings clear to make power.
--mapmaker

My installer didn't seem to be aware of this "snow country" practice; in fact I haven't noticed ANY panels
mounted landscape here. Maybe that will change. If I lost the bottom row of cells in many panels, I think
the whole string would drop out. It would be dominated by the parallel strings with no blockage, at full voltage.
Bruce Roe

[mapmaker]

If I build any more platforms, panels will be landscape (to reduce the distance for snow to slide off). I am wondering, why no one ahead of me has made such a suggestion?

It is standard procedure in snow country to put panels in landscape orientation, but not for the reason you mention. Within most solar panels are several strings of cells in parallel. The strings run vertically if the panel is in portrait orientation and horizontally if the panel is in landscape orientation.

Snow slides down the panel and gets caught up on the lower frame of the panel. In portrait orientation, the snow blocks the lower part of each string of cells within the panel (no power). In landscape orientation, the snow entirely blocks just one string of cells and leaves the other parallel strings clear to make power.

Also popular in snow country are black-framed panels... they accumulate less snow than white or aluminum frames.

--mapmaker