How do you deal with freezing rain, or crusty snow that can't be brushed off?

[iceledoar]

In this case there is really no difference between a rheostat or a potentiometer. whatever you call it you are putting a variable resistor in series with the panel. I have always wondered why there is two different names in the first place. They are fundimentally the same thing that is used in different ways. It is kinda like the difference between a relay, a contactor and a solinoid.

Let’s not forget the dimmer switch.

 

[Rbertalotto]

My 10.5Kw panels are on the roof of my 2.5 story house and can not be reached. This winter has been very mild in Southeastern Massachusetts so it hasn't been an issue this year. But most years the panels are covered from end of December to Mid March!
I always wondered why the panels were not designed to self heat at X degrees.
If I had enough land I would rather ground base the array. Then I could service them or at least spray them with PAM cooking spray.

 

[Red Squirrel]

That's my issue too if I decide to put panels on the house, they would be at the same angle as the shed ones, except I would not have enough ground clearance to get to them with the long broom due to the angle of the roof. Ex: I would have to back all the way up to the neighbour's house and still not have enough reach with the broom as they would still not be line of sight. Would almost need to put scaffolding permanently.

I sure wish I had more land so I can do a good ground mount system. Been looking into off grid land though to build a camp as I do eventually want to live off grid. Then I can really have lot of fun with proper solar and wind setups.

 

[mtt04]

I'm up here in Nova Scotia Canada.

I hear some folks have put a divert load used for wind power fastened on a rail under the panels.
They then have a typical battery divert switch that is 3 way.
basically they power direct from the batteries.

3 way divert switch has one pole going to the batteries, one pole to the divert load, one pole to the charger and they re-direct 12v power to the divert load bar. Basically they are cutting off the charge controller and running direct current from the batteries to the divert load.

I'm not sure what wire size they use for the divert load but it would be distance and amp rated.
The divert load bar heats up under the panel and warms the panel.

I haven't bothered to it because I'm not up at the cabin in the winter much.
I'd look at some google searchs and see if there is a diagram somewhere

 

[kernel]

best course of action at my ranch.....

 

[Red Squirrel]

That's sorta what I have in mind too but I would just use thin wire taped/glued under the panel kinda like a heated floor system, and put a temp sensor to regulate the temperature (just need it to be like +5c or so), then foam board over it (from under the panel). In fact I'm now thinking if I can design this thing as a bolt on module I can build it and test it on the bench before then installing it in production. I'm thinking it could be a casing that goes behind the panel but also has some kind of air baffle at the top and bottom which I can open in summer only then close it in winter. Would essentially heat it from the back and trap the heat there. At least that's my theory. I basically have less than 1kwh to work with if I use battery power so it will need to be able to do at least one panel so I can start producing. It could take several days to get back to full operating power but it would be sufficient as we don't get freezing rain that often. For the rest I would still be brushing it off normally until I find a way to automate that too.

 

[Red Squirrel]

Managed to get a good chunk of the snow off the solar panels. Because it was all crusty and crap I could not brush it last time I tried but I had the idea to turn the brush around and I can use the handle to drill a bunch of holes and then criss cross the patterns until I can make it weak enough so leverage can break it off and it worked.

Still at least an inch on there but at least the weight is off them. Lot of it managed to evaporate (sometimes snow does that when it's warm but not super warm) but still it would get very heavy in spring if I left it especially since there's still more storms ahead of us.





This summer I'm continuing on converting my unfinished garage to a shop (insulating, heating etc), so after that there are tons of projects I'll be able to work on year round and an automated brush system, as well as heated pads is going to be on the agenda, and I'll try to do it before winter comes.

If I can actually get an automated system going that can handle the snow AND freezing rain, then it might make it viable to put solar panels on the house too. I have room for up to 3kw but really more like 1kw without putting them in really weird orientations. 1kw would be decent though as I could make it run some of the "always on" circuits around the house like fridge, freezer etc. Maybe even servers. I would still have rectifiers to keep batteries topped up but at least in the day that stuff would run for free.

 

[EllaBella]

I don't live in a cold climate, just a wet one but I have used glue on heating pads to my van underslung water tanks to prevent them from freezing in cold conditions.

Could you do the same here? Could you mount a heating pad to the back of your solar? You could remove the worst of the snow and then let the heating pads warm them just enough to melt the layer of ice in contact with the solar, allowing it to be brushed off easily?

 

[offgriddle]

I find with climate change we get way more weird weather patterns here now including freezing rain or wet snow. This ends up causing a crust on the panels which cannot be brushed off like regular snow. I have a 400w system on my shed which I just turn off completely in winter but it would be cool to run power to the house and run it year round. Last year I sorta had it running year round to keep the battery topped up but no load. Every morning (if I remembered) I would snow shoe to the shed and use a long broom to take snow off. At one point in December though we got freezing rain, so I was not able to broom it right down to the glass for the rest of the year as it just made a crust.

This is basically as good as it got:



That is not regular snow but a more crusty ice/snow, so it's not physically removable without serious brute force, like on a car windshield, but I don't want to use that kind of force on panels.

How do you guys deal with this? I eventually want to live off grid so this is more or less a pilot project. My first thought is to change the incline of the panels so they are vertical, downside with a roof mount is that they will act as a sail and put a lot of stress on the roof when there are wind gusts. Another thought is to run thin wire behind them like a heated floor application and basically melt the ice away as needed, but this would require a much beefier battery. Ideally I should just need to melt the under layer and I should be able to get it off with the broom. In an off grid application and a much larger array I could replace the wire with pex tubing and glycol and run it through a boiler.

For general snow removal been toying with some kind of automated brush on a rail system that sweeps them hourly, maybe this would take care of freezing rain too by wiping them down? Downside is the bristles would get all icy after.

Anyway just curious what others have done to deal with this so that they can be used year round. I know it's also possible to backfeed power into the panels but I don't really want to mess with that. A mistake could be disastrous.

I have discovered that what doesn't easily brush off suprisingly quickly melts away on it's own during the day even on cloudy and otherwise below freezing days.

 

[offgriddle]

I don't live in a cold climate, just a wet one but I have used glue on heating pads to my van underslung water tanks to prevent them from freezing in cold conditions.

Could you do the same here? Could you mount a heating pad to the back of your solar? You could remove the worst of the snow and then let the heating pads warm them just enough to melt the layer of ice in contact with the solar, allowing it to be brushed off easily?

that's a good idea

 

[offgriddle]

Managed to get a good chunk of the snow off the solar panels. Because it was all crusty and crap I could not brush it last time I tried but I had the idea to turn the brush around and I can use the handle to drill a bunch of holes and then criss cross the patterns until I can make it weak enough so leverage can break it off and it worked.

Still at least an inch on there but at least the weight is off them. Lot of it managed to evaporate (sometimes snow does that when it's warm but not super warm) but still it would get very heavy in spring if I left it especially since there's still more storms ahead of us.





This summer I'm continuing on converting my unfinished garage to a shop (insulating, heating etc), so after that there are tons of projects I'll be able to work on year round and an automated brush system, as well as heated pads is going to be on the agenda, and I'll try to do it before winter comes.

If I can actually get an automated system going that can handle the snow AND freezing rain, then it might make it viable to put solar panels on the house too. I have room for up to 3kw but really more like 1kw without putting them in really weird orientations. 1kw would be decent though as I could make it run some of the "always on" circuits around the house like fridge, freezer etc. Maybe even servers. I would still have rectifiers to keep batteries topped up but at least in the day that stuff would run for free.

My panels seem to be tilted considerably more than yours, (for maximum winter gain), maybe tilting more would be helpful.

PS: I'm trying to find a protective, "eve sleeve", similar to the one you are using on your wires. So far I have searched the internet and several local electrical supply houses to no avail. Could you share the vendor and part number and approximate price you paid if you have it? Thank You.

 

[Red Squirrel]

Yeah the heat pads is basically what I plan to do, but it will just be more DIY with thin wiring and a custom SMPS so I have more control over power draw. The tilt angle is a problem too, it was just easier to keep them the same as the roof pitch but I might try to see if I can angle them more. I just have to be careful I engineer it right so that wind forces are spread out evenly on the roof mounts as it will act like a sail if they are tilted more up. There are only 8 total lag bolts holding the whole thing together and we get the occasional wind gust storms here, where we get these huge bursts of wind at random. They can hit completely out of nowhere, it can be a nice day, then suddenly it feels like a transport just hit the house. I'm thinking if I tilt them, but add weights at the back of the tilted part, it might help translate some forces when the bursts hit as there is more mass to pull up.

Not too sure what you mean about the eye sleeve, if you're talking about where the wire comes off the edge of the roof it's literally a grocery bag. I want to do a more permanent solution with conduit though, this was a temp thing "for now" and it ended up staying longer.

 

[EllaBella]

Yeah the heat pads is basically what I plan to do, but it will just be more DIY with thin wiring and a custom SMPS so I have more control over power draw. The tilt angle is a problem too, it was just easier to keep them the same as the roof pitch but I might try to see if I can angle them more. I just have to be careful I engineer it right so that wind forces are spread out evenly on the roof mounts as it will act like a sail if they are tilted more up. There are only 8 total lag bolts holding the whole thing together and we get the occasional wind gust storms here, where we get these huge bursts of wind at random. They can hit completely out of nowhere, it can be a nice day, then suddenly it feels like a transport just hit the house. I'm thinking if I tilt them, but add weights at the back of the tilted part, it might help translate some forces when the bursts hit as there is more mass to pull up.

Not too sure what you mean about the eye sleeve, if you're talking about where the wire comes off the edge of the roof it's literally a grocery bag. I want to do a more permanent solution with conduit though, this was a temp thing "for now" and it ended up staying longer.

Could you place some rigid sheeting on the sides and back at an angle to act as a wind deflector? So rather than the wind getting under the back of the panel, it's directed up and over? Kinda like a wind deflector on the front of a van or lorry?

Could be made out of plywood or some thin metal sheeting?

 

[ghostwriter66]

I have discovered that what doesn't easily brush off suprisingly quickly melts away own its own during the day even on cloudy and otherwise below freezing days.

View attachment 8732

This is when i mention that last week we had highs in the low 80's and this week the weather guys are forecasting 90 degrees this WED and THURS (south Texas desert) ... our biggest issue is DUST that starts getting caked on ... I would take snow any day of the week -- that dust crap lasts until the next good rain .... and then the cycle begins again ...

 

[EllaBella]

This is when i mention that last week we had highs in the low 80's and this week the weather guys are forecasting 90 degrees this WED and THURS (south Texas desert) ... our biggest issue is DUST that starts getting caked on ... I would take snow any day of the week -- that dust crap lasts until the next good rain .... and then the cycle begins again ...

Could you use an anti static glass cleaner? A lot of dust clings to glass due to a tiny static charge.

 

[offgriddle]

This is when i mention that last week we had highs in the low 80's and this week the weather guys are forecasting 90 degrees this WED and THURS (south Texas desert) ... our biggest issue is DUST that starts getting caked on ... I would take snow any day of the week -- that dust crap lasts until the next good rain .... and then the cycle begins again ...

I never imagined dust clinging to and building up in layers sufficient to significantly reduce solar gain, a difficult problem indeed. Still, are you sure you would like five months of cold, snowy weather follow by five months of warmth but with lots of rain, mosquitoes, black flies & ticks all for two months, (September & October), of scrumptious weather only to begin the same cycle over again? Hmm?

 

[offgriddle]

Could you use an anti static glass cleaner? A lot of dust clings to glass due to a tiny static charge.

First the panel warmer idea and now the static brush idea, you have good ideas!

 

[Steve_S]

Could you use an anti static glass cleaner? A lot of dust clings to glass due to a tiny static charge.

It is NOT advisable to use ANY glass cleaner or chemical on solar panels. Just hose them off if they get dusty. Many class cleaners can actually etch the glass if it is hot when the crap is applied. NEVER use Vinegar either... just plain water ! IF there is bird poop or something nasty / sicky, a little dish soap & warm water and a "soft cloth, preferably microfibre" and light work will clean it.

 

[offgriddle]

It is NOT advisable to use ANY glass cleaner or chemical on solar panels. Just hose them off if they get dusty. Many class cleaners can actually etch the glass if it is hot when the crap is applied. NEVER use Vinegar either... just plain water ! IF there is bird poop or something nasty / sicky, a little dish soap & warm water and a "soft cloth, preferably microfibre" and light work will clean it.

Why not vinegar? Corrosive to aluminum & electrical connections and not slick enough to prevent scratches?

 

[Steve_S]

Vinegar etches glass is left on it. It is a mild acid. Solar Panel docs also mention NO CHEMICALS but hey, what do they know right.