Solar panel and snow load

[colliehauler]

I would like to put a solar panel on a RV that I leave in North MN. Will a panel take the snow load and -40 temps? I know it will not charge under the snow but should charge in the fall and spring.

[Almot]

Keep in mind that most so called "flat" installations are slightly tilted, because it conforms to the roof slope. Unless your roof is totally flat - and in this case you'd better install the panel with slight slope, about 3 degrees, to drain the water and dust. This will help against snow accumulation as well. Lift one side (the one that is more likely to be the North side) about 3/4"-1" higher than the other side. Don't worry if the lifted side will become the South side at times - minus 3 degrees won't do much harm, and the other times it will work better than flat.

Landstar looks like a decent controller - it says "setpoints user defined" ? - if this is so, it's good.

[MrWizard]

sounds like you have a plan
should work in the situation you described

[colliehauler]

Mr Wizard- The guests will not use it of a winter. Now doing nothing the battery stays in the good on the trailer battery check leaving it sit from Sept until May. I could leave it on a battery maintainer but was looking for a way for the guests not to have to put the battery in before use. The battery would be fully charged before the snow hit and the snow would be gone before anyone would use it in the spring and should have the battery back up to full charge. The battery maintainer would be $125. less then the solar.

[MrWizard]

Your 900 miles away, but the guests Use It in the middle of winter and snow ?

Solar is great as long as the panels are clean, snow won't hurt them, but your battery is not going to be charged,
Sun for summer storage and charge fine
Winter pull the battery out, just my opinion

[westend]

colliehauler wrote:
Westend-I have a battery disconnect switch on the trailer, the panel is just to keep it topped off.

Good deal. Then all you have to figure out is how permanent of a mounting aspect you wish and what will work easiest. If the rig is parked and no one is going to be hauling it on a regular basis, you could probably get by with a pole mount of some kind and wire into the controller, situated close to the batteries. If you can figure out an easy detachment method (Anderson power pole fittings come to mind), anyone that is up there and wants to move the rig can store the panel and detach the module-to-controller wiring within minutes.

I have my tilted module set at 59 degrees. If you're up around Lake of the Woods or similar latitude, you can even tilt more. More tilt is better since it helps to shed snow. The MNDOT accessory road sign modules are tilted to about 80 degrees, for reference.

I just took a gander at my module and what was previously a cover of 8" of wet, frozen snow is now 1/4 gone after a day. Even at 5f, the module will have melted most of the snow off in a day or two. It's not critical to me because I'm not using the trailer and the batteries are fully charged.

Good luck with your solar charging, it is really a great thing, once setup properly.

[colliehauler]

Westend-I have a battery disconnect switch on the trailer, the panel is just to keep it topped off.

[westend]

The larger solar modules are rated to almost twice what a typical residential roof will bear for weight. Don't know about smaller ones but would assume they are the same.

I have my panel tilted but have been up on the roof twice to clear snow from the bottom. With a smaller module, you would need to put it up on a stand and tilting, pointed South, in Northern MN to make it effective. This year, the stand would need to be >3' high. If you are going into storage season with fully charged batteries, you may be OK, as long as there is no parasitic or other draw from the 12V system. AGM's make a lot of sense in this application but you still need a disconnect from any draw.

There's nothing set in stone that says you have to pull wire through the RV. Depending on where your controller resides and position of batteries, it may be easier to have the module to controller wiring on the exterior.

[colliehauler]

Thanks for the replies. Just wondering where you run the wire down from the panel? The only place I see would be the frig vent. Pianotuna-It says 10 amp controler adopt temp compensation will correct charge /discharging parameters automatically to improve battery life. The brand is a SUN GOLD SOLAR 85 watt panel with a 10 amp LAND STAR CONTROLER. Mr Wizard-Would like to not have to take the battery out every time not in use, spare RV for guests. I store it where there is no power, unless they move it to a site.

[free_radical]

colliehauler wrote:
I would like to put a solar panel on a RV that I leave in North MN. Will a panel take the snow load and -40 temps? I know it will not charge under the snow but should charge in the fall and spring.

Most can take a golf ball size hail pounding without problems,snow should be no problem..

[MrWizard]

I think better off to just, take the batteries out
You could have several months where the panels are not putting out any power, due to being covered up with snow

[pianotuna]

Hi colliehauler,

My panels have survived -37 c and lots of snow.

Do be sure to use a temperature probe on the battery bank.

[colliehauler]

The RV is 900 miles from home so I will not see it until spring.

[ed6713]

I live in CO. Several inches of snow routinely accumulate on the panels with no problem. I clean the panels after each snow so the batteries can stay charged during the winter months.

It doesn't get to -40* around here but 0* isn't a problem.

ed