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-   -   How bad is snow for people with solar and roof racks? Is it worth it to heat it? (https://www.skoolie.net/forums/f13/how-bad-is-snow-for-people-with-solar-and-roof-racks-is-it-worth-it-to-heat-it-35154.html)

Truffles 03-09-2021 10:36 AM

How bad is snow for people with solar and roof racks? Is it worth it to heat it?
 
Hi all,

Problem: I have been wondering for a while how you people with solar and roof racks deal with snow. It seems like it would be difficult/dangerous to clean the snow off the roof after a large storm if you have to move before it melts. If you don’t clean it, it would seem like there is a potential for snow to fly off in a way that could hurt someone on the road.

Solution?: I was considering adding a loop to the hydronic heating system to heat the roof of the bus and try to keep that stuff melted if we plan on moving any time soon. This may prevent large chunks of snow from settling, while having the benefit of keeping light snow from obstructing the solar panels.

Is that dumb? Does a heated bus already naturally keep the snow off without the need to complicate things?

I would imagine that this would lead to a big chunk of ice at the base of the bus that may cause its own problems. But one step at a time.

s2mikon 03-09-2021 02:20 PM

My panels are flat. Yes they are reduced in output that way but in the summer here they put out 235-245 watts. They are 290 watt units. When it snows like last month they put out 0! As far as sweeping the snow off I'm not going to risk falling off a slippery ladder. As far as driving off with snow on the top, truckers do it all the time with trailers. If someone wants to tailgate that close to hell with'em. I have thought of a loop of copper pipe running under them to warm them up but I just use the pedal on the right and a compass pointing south.

Ronnie 03-09-2021 05:19 PM

Snow here in Virginia usually does not stick around more then a few days so I never worry about it.


I do have a ladder built on the back of our bus, and a low railing along the edge, plus non slip paint on the roof. So not to concerned about getting on the roof to clear snow off the panels if it did not melt soon enough.

peteg59 03-09-2021 06:39 PM

Needless to say a 6" snow covering will block out any solar action, (based on what a friend has told me). Probably 1" of snow would have the same effect? Don't have solar, so I can't speak from experience.

It is a misdemeanor to drive with snow on a vehicle roof here in snowy NH.
Megan's law or something. Passed a few years ago, named for a poor young girl who lost her life due to a tractor trailer shedding its trailer's snow/ice load on the highway that penetrated the windshield of her mothers car and basically decapitated her.

Amazing how heavy a thick ice/snow load actually weighs, and the damage it can do to an unlucky motorist who happens to be travelling behind a truck when it eventually breaks free.

It basically goes for all vehicles, not just commercial truckers. If the State Police see it on a vehicle, the operator will get stopped and likely ticketed.
Serious shiite right there.

dwood443 03-09-2021 07:13 PM

Quote:

Originally Posted by peteg59 (Post 429769)
Needless to say a 6" snow covering will block out any solar action, (based on what a friend has told me). Probably 1" of snow would have the same effect? Don't have solar, so I can't speak from experience.

It is a misdemeanor to drive with snow on a vehicle roof here in snowy NH.
Megan's law or something. Passed a few years ago, named for a poor young girl who lost her life due to a tractor trailer shedding its trailer's snow/ice load on the highway that penetrated the windshield of her mothers car and basically decapitated her.

Amazing how heavy a thick ice/snow load actually weighs, and the damage it can do to an unlucky motorist who happens to be travelling behind a truck when it eventually breaks free.

It basically goes for all vehicles, not just commercial truckers. If the State Police see it on a vehicle, the operator will get stopped and likely ticketed.
Serious shiite right there.


Iím guessing my son and I were lucky so many years ago. My son around 6 or seven in the front seat and I on the highway in winter here in north east Ohio.
A truck got on in front of us that must have been parked overnight. Snow and ice flipping off the roof. Just as I told my son we better watch out a piece as big as the car hood flipped off and landed on my hood and then into the windshield. Needless to say the hood seriously dented and the windshield shattered.
My son and I was covered in shattered glass. luckily we were able to safely pull over to berm. My son was not hurt at all but I almost hard a heart attack.
Now I avoid any kind of snow/ice flipping off cars or trucks. I had no idea that stuff was so dangerous.

Sehnsucht 03-09-2021 07:19 PM

Not speaking from experience, just being practical here, but what if you mount the panels at an angle like a roofline or mount them so that they can be repositioned somewhat? As far as I can tell houses with solar panels on the roof have no problem shedding snow accumulation so if your schoolie has them mounted at an angle maybe with a peak down the center the snow should slide off before it accumulates or if it does manage to accumulate it'll slide off when the weight overcomes the friction of the panel's surface which can't be much I'd imagine.

As for snow loads on truck roofs, yes people have no idea how much or how heavy that is! Several states have passed laws but like most near-sighted legislation they didn't consider how they expect truckers to clear the snow off the roof! Some facilities have a roof scraping mechanism but they're not commonplace nor are they all-access. Any state passing such a law needs to have scrapers installed at all weigh stations, rest areas, and truck stops so that drivers aren't ticketed for something that have no recourse to address.

TJones 03-09-2021 07:21 PM

I have also been wondering if it is worth it to install solar panels since I will using my bus mostly in the snow. I am thinking the combination of snow, frost, and road grime will require frequent cleaning.

One of these might help.

https://youtu.be/FE6f8vcDImo

Ted

Iceni John 03-09-2021 07:52 PM

Quote:

Originally Posted by TJones (Post 429782)
I have also been wondering if it is worth it to install solar panels since I will using my bus mostly in the snow. I am thinking the combination of snow, frost, and road grime will require frequent cleaning.

One of these might help.

https://youtu.be/FE6f8vcDImo

Ted

If you're serious about maximizing solar harvest in the winter, the panels need to be tiltable to face the sun as best as possible. This means they need to raise to about 45 degrees, or more in higher latitudes, to have any chance of producing meaningful output. At that angle most snow will slide off them. And as for cleaning them, something that most folk don't incorporate into their PV installation, it's prudent to build a walkway on the roof so you don't fall off while washing them, and then it's easy to also add one or two water outlets on the roof to plug a washdown brush into, making the monthly panel cleaning a simple and safe 5-minute job.

John

Rivetboy 03-09-2021 10:08 PM

Hey John, what kind of connector are you using on the roof?

Joe

musigenesis 03-09-2021 10:41 PM

Quote:

Originally Posted by Truffles (Post 429716)
Does a heated bus already naturally keep the snow off without the need to complicate things?

If your ceiling is well-insulated, the snow up top might stick around a lot longer than you think. We had a few snow storms this winter that left 4-6" of packed snow and ice on my roof. I assumed it would come off the first time I hit a bump but it stuck on there like a hairpiece on a personal injury lawyer. It stayed up there for days even though I was heating up the bus inside to 60į to 70į every day. I finally had to knock it all off with a snow shovel wielded from a ladder since I wasn't going to go out on the roof. I definitely need to build something like what Iceni John suggests, a small walkway of sorts on the roof that I can safely use to knock snow off.

Truffles 03-16-2021 11:30 AM

So it seems like the general consensus us that snow can be a problem for both solar panels and other drivers on the road. I am not sure that tilting the solar panels would solve the problem of having a ton of snow stuck up top, intermingled into the brackets that the solar is mounted to.

Since it will be relatively inexpensive to just add a zone to an already planned hydronic heating system, it seems like that is going to be the direction I go. That way, I can make the pipes run between the roof and the insulation intended for the ceiling. My wabasto diesel heater that came with the bus isn’t going to flench at melting snow, and to be able to keep the solar panels clearer than they otherwise would be, it’s worth it.

Now, what would be the best way to get the pipes to transfer heat to the roof? Should I run them front to back, between the framing boards? That would mean it would really only contact the roof at the ribs. Maybe it would be better to have it zig zag back and forth along the corner of the roof and the rib.

Decisions decisions.

GreatPlainsBus 03-20-2021 03:54 PM

Our panels are tilted just slightly, about 15-20 degrees, and I've found that snow only rarely accumulates on them. I think a big part of that is the never ending wind of North Dakota, but even the few times we got snowed on in Wisconsin it didn't stick to the panels. They're slick enough that it just doesn't stay on. That said I'm glad I have a way to access them when they need to be cleared before driving.

All in all it does happen sometimes, but with some tilt I don't see it being a constant problem to where heating your whole roof would be beneficial.

GreatPlainsBus 03-20-2021 03:57 PM

Side note, snow definitely accumulates on the roof itself, so you'll want a way to clear that before driving. I guess it all depends on how often you're on the move. If you're stationary a little snow on top is just extra insulation.

Florida Ranger 03-20-2021 04:38 PM

Donít have to worry about it collecting on solar panels here on Floridaís Gulf Coast I really do Feel bad for those of you that have this problem. But I canít quite Reach you. Stay Safe ..

Whiskey.Wilderness 03-20-2021 06:08 PM

We are going with flexible panels so we can curve them to the roof shape- we spent winter here in Colorado with the bus already and found that the snow falls off of its curved roof pretty readily so panels curved to it shouldn’t be a problem once we install them and I’m also gonna keep a layer of rainx on em to help in the future too helps keep snow/ice from sticking to em

Simplicity 03-21-2021 02:54 AM

I feel this issue is mute unless you know you are going to be using your bus a LOT in areas of snow/ice during that season. If this is simply a "oh, what if we get caught in a snow storm" kind of thing, then I'd just deal with that when it happens. You don't buy a snow thrower to clear your driveway twice a year.

If you are going to be traveling in snow country during the snow season, than my suggestion for dealing with it are:

Using the broom part of a push broom, MacGyvered a handle to be able to reach up and over to the middle of your bus from the sides. Pull the snow from the center of the bus off the roof.

Use 70% Isopropyl alcohol in a 50/50 mixture with water. It melts ice right off windshields, so it should work the same for solar panels and roofs. That's basically what they put in the winterized windshield wiper solution.

Use a framework of wire with a 12v current running through it to loosen the snow so it comes off easier. Look at your back window of your car, that's what they use to defrost the back window. Amazingly effective. It's also similar to wrapping outside water pipes with electric cords to keep the pipes from freezing.

Use a combination of any of these to address your situation.

Best of luck.

rgjarrell 03-21-2021 03:52 AM

Homeowners have been putting a wire along the spots of a roof in northern parts of the country for a long time to melt ice dams and prevent ice dam roof leaks.

https://www.amazon.com/dp/B00527FMMC...ing=UTF8&psc=1

cadillackid 03-21-2021 09:32 AM

it doesnt take much dark solar panel showing through the snow to get melting started.. seems if you broom off a good bit of it then the dark spots showing through will get warm pretty quick.. and if its cloudy out in a cold place in winter your solar is probably not doing much anyway due to very low energy through clouds during low sun-angle..



drive to florida? thats the way I like to think about winter

Iceni John 03-21-2021 11:02 AM

Quote:

Originally Posted by Rivetboy (Post 429806)
Hey John, what kind of connector are you using on the roof?

Joe

Sorry for the late reply! I'm using the panels' original MC4 connectors that plug into home-made 10AWG extension cables that then run into each side's combiner box. If I ever needed to change out a panel, it would be a simple 5-minute job this way.

John

o1marc 03-21-2021 02:23 PM

Quote:

Originally Posted by Whiskey.Wilderness (Post 431372)
We are going with flexible panels so we can curve them to the roof shape- we spent winter here in Colorado with the bus already and found that the snow falls off of its curved roof pretty readily so panels curved to it shouldnít be a problem once we install them and Iím also gonna keep a layer of rainx on em to help in the future too helps keep snow/ice from sticking to em

AIUI, flex panels mounted on the surface of the roof have a tendency to overheat and reduce effectiveness. Any panel mount off the surface would not benefit from hydronic heating of the roof.

When it starts snowing I go south.:thumb:


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