snow melt ?

[mike90045]

So, what happens when you back feed 48V into a 160V array to try to melt snow?   Does it only work if you have a 60V array?  If the array nominal voltage is high and batteries/generator much lower, can you get any melting power to backfeed, or is it only a couple watts ?
Covered in snow and ice this am. Poles too stout to whack with an 8"x8",  not shaking loose.  Only making 60W under the clouds & snow

[russ_drinkwater]

We need rain send some melted snow here please!
40deg C outside a lot of days, no chance I will ever see snow on the panels!
Got a petrol powered hairdryer?

[TomW]

I wonder if simply shorting out the panels (after disconnecting from controller) would help speed defrosting?

That would produce all the heat in the panels from the power they are making and shorting panels is harmless to them. In higher voltages the arcing might be an issue with the switching gear.

Just a thought I had.

Tom

[mike90045]

I wonder if simply shorting out the panels (after disconnecting from controller) would help speed defrosting?.....

My 5Kw of array was making about 100w at noon,  spreading that over the surface of the array will do .....  0 !

If there was enough sun for appreciable "shorted heating", the panels would be producing power and warming themselves.

I'm wondering what sort of voltage needs to be applied in relationship to Vmp to melt stuff.    Several years, and I've had no issues, but now this super cold stuff comes, and it's become so reflective, I'm on day 3 of 100% generator.  Happy new year to me.

[boB]

We needed to melt snow off our engineering array last week but I didn't...

The voltage to turn the PV into a space heater has to be just about or slightly above
the Voc of the panels, whatever that happens to be.  I wouldn't try this though
because the series fuses will probably blow before you can give them enough
power to melt the snow.

I find that if it is too cold and/or the snow/ice is too thick, it just isn't going to work
very well.

It sure is fun though when it works !

boB

[toothy]

Try typing in "snow rake" the plastic ones work pretty well on hard to reach panels. Once you get most of the white off it goes fairly fast with a bit of sun. I've become a bit obsessive about this with our short days.

Wade

[robbertwilliams]

Try a telescopic Libman Floor Squeegee.  The panels in the winter should be nearly vertical.  I've only had issues with a couple of inches sticking.  The floor squeegee works perfectly, then the black in the panels helps melt the rest.

[CDN-VT]

I bought a snow rake
https://www.homehardware.ca/en/rec/index.htm/Outdoor-Living/Yard-Maintenance/Snow-Removal-Aids/Tools/Gen-Purpse-Snow-Rake/24-Telescopic-Roof-Rake/_/N-ntlmu/R-I5551487

And I made a rubber wiper so it's to glide over , the tube also has a pressure washer of -39 C blue anti freeze if needed

[niel]

hi mike,
can you change the angles on the arrays for they seem semi-flat for somebody in northern cal. as you know the higher angled the pvs sit, the less likely snow will stick to it. you don't have much snow on them, but without the sun beating down it tends to stay making overcast days even less productive. other than this, you need to physically remove the snow like with a roof rake or something similar. once any of the black surface face appears it tends to speed up the melt even with overcast unless your temps dip way down as to offset the btus of the sun.

another thought to try is to clear 1 pv of a string and the power produced by the clear pv will force itself through the other pvs in the series string and may help speed the melt process. it'll be too slow for most of our patience i'm sure so try to clear them all of some snow.

[mike90045]

The arrays are actually at about 45 deg, the limit of the adjustment arm.  The 10 panel array lower edge, is about 16' off the ground, to clear clumsy truck drivers & wired side to side S5P2.   The other array (back by the shed) is much lower and I could use a snow rake on it to clear the lower row (wired top to bottom) S4P3

[CDN-VT]

I find if I clear the bottom section so the black / blue panel can see the sun , It grabs enough heat to let above slide off .Thats if say I have under 25mm/ one inch or so , When Im deep , its full snow rake pulling.

VT

[niel]

ok, well if you would like to try something simple i thought of, it may speed the process of the melt. get a long rope and throw it over the whole array. it may be difficult to place the top of the rope at each upper pv, but once there just be on the ground with both ends and push/pull it back and forth while slowly moving it left or right. this could clear some spots well enough to start the heating of the pvs from solar radiation. if you try it let us know if it helped.

[niel]

cdn-vt may have part of the answer as putting windshield washer fluid into a good squirt gun and fire on the array could definitely get things started.

[russ_drinkwater]

Just do not got with britians use of salt on the roadways to help stop snow and ice buildup!
I think a liberal coating of fine salt on the panels would be a tad corrosive! Lol.
And drop efficiency  off the charts!
Like the idea of the windscreen spray in the squirt bottle.
I was on the roof the other day and noticed the wife's cats have tried to help our solar production by vomiting over 2 panels!
I have never seen chunder spread so far!
Made my trigger finger itch!
Sorry to any cat lovers out there.
I could hire the cats out to you as the warm spew may assist with the snow melt process?

[TomW]

Just do not got with britians use of salt on the roadways to help stop snow and ice buildup!
I think a liberal coating of fine salt on the panels would be a tad corrosive! Lol.

I read about the Canuks using beet juice to treat roads. Non corrosive, organic, natural, etc.

Lowers the freeze point of water so, apply to surfaces ahead of time it prevents ice from bonding to the road so it breaks up.

Sounded effective

Never heard of it before.

Just a thought

Tom