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Small Cabin Forum / Off-Grid Living / Grid Tied Solar?
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itsals1
Member
# Posted: 9 Mar 2017 08:16
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I realize this is designed for small cabins,BUT there are some very Super
Solar Savey members here.
My wife and I are wanting to install a 10 kW system at our country home.
I have talked to the people at Solar World. My biggest concern is ground mount vs roof mount system. Our HVAC geothermal has started installing these systems and really, only want to install ground mount systems. My wife and I are thinking of building a 48'x40'x10 stick built building with pole shed steel on the roof and walls to mount the solar panels to the South facing roof.
We are in Eau Claire WI, so we will have snow, but I doubt I will ever brush snow off the panels on a ground mount.
Any and all suggestions?

Thank you!

Steve_S
Member
# Posted: 9 Mar 2017 09:15 - Edited by: Steve_S
Reply 


With Ground Mount you can have them as tracking the sun which would increase power production significantly but it comes at a cost.... Those tracking systems are not cheap ! IF something goes awry, easier to get at and repair / replace on a ground mount vs roof mount.

* 500W panels will be available this year, a few are showing up already and like all things, more will be available soon. That of course means that lower wattage panels will get cheaper BUT remember the old "penny wise / dollar foolish" warning... Be careful with your shopping and really think it through. Any "high pressure" for a sales person is a warning flag, so Caveat Emptor ! The price per watt is always more on higher capacity panels but there is a payback that isn't immediately obvious till later when you say "I should'a, could'a & would'a but DAMN I didn't".

Fixed Mount on a roof is a set of compromises and as your building new somewhat less problematic. You can better build to get a more efficient angle / pitch but you won't get the same production capability from east or west nor seasonally... That's the compromise BUT a typical trick by us Canadians is to over-panel a bit to make up for the difference, so a couple more panels = cheaper than a tracking ground mount. simply put

FYI: If your attaching to grid, planning on rebates / incentives be aware that many vending installer's will charge max they can because you the consumer will be getting rebates etc... Case in point, I knew what I needed & wanted, went to a local dealer who is a Micro-Fit dealer (our incentive program) and his quote for all parts was MSRP and for a couple of thing MSRP+ 10% and his estimate was just under $21,000 ! Well, I knew the prices, so I shopped more and found an ethical dealer who sold at proper market value, total cost from them was $9100.00 and I bought my Inverter/Charger Combo from another dealer for < $700... so all in for under 10,000 VS the bad dealer at double ! NO JOKE and that High Priced dealer is still in business and just bought his 3rd Tesla for his daughter.

Hope it helps.

EDIT: Here is a link to a Angle to Roof Pitch converter so you can figure out what roof pitch would be best for you. It appears a 45deg or 12/12 is the median, which is a pretty sharp angle.
http://www.blocklayer.com/pitchangle.aspx
NB: Enter the angle value and click the [angle] button which will provide the rest of the numbers.

ATTACHED is the Optimal Solar Angles for Eau Claire WI
Eau Claire WI Optimal Solar Angles
Eau Claire WI Optimal Solar Angles


creeky
Member
# Posted: 9 Mar 2017 09:31
Reply 


I would build the barn and put the panels on the roof. Make sure you get the trusses engineered for the panels. there will be code issues.

You have a lot of good incentives right now and the US market is booming. So be prepared for that. That might be the advantage of getting someone just moving into the market. They're not crazy busy?

SolarEdge and their optimizers seems to be the way everyone is going. I hear good things.

And get a plug in hybrid or an electric car. From the samples I've seen, swapping out the gas cost turns the pay back from 7-8 years into 2-3.

I would love to take my truck gas bill and turn into free. Good luck.

Wilbour
Member
# Posted: 9 Mar 2017 09:46
Reply 


Quoting: creeky
And get a plug in hybrid or an electric car. From the samples I've seen, swapping out the gas cost turns the pay back from 7-8 years into 2-3


Would love to get the new Tesla 3 and run it for free!

Steve_S
Member
# Posted: 9 Mar 2017 10:06
Reply 


Here is an article from Canadian Auto Trader which is somewhat enlightening (ok shockers too, some good & bad)
http://www.autotrader.ca/newsfeatures/20170302/how-much-does-it-really-cost-to-charge -that-electric-vehicle/

Maybe someone has done something similar for the States (I looked and can't find it easily)

IF you can juice one yourself from your solar system... that would be a sweet deal. NOW if a smart company would finally come out with the 21st Century equivalent (mentality wise especially) of Henry Ford's Model-T. Affordable, easy to maintain and designed to get everyone driving ! Who needs autodrive and all the flashy extras... simple 4 door, a to b, reliable, cheap no junk... But then you can't even buy a conventional gas car without a heap of junk tossed in.

creeky
Member
# Posted: 9 Mar 2017 11:16
Reply 


There are a bunch of folks who have done this already.

The payback is ridiculously fast. I mean I pay 100/wk for gas and I don't drive that much. Somebody commuting?

Hard to beat a 2-3 year pay back. Plus heat/cool your house.

Solar rules!

bldginsp
Member
# Posted: 9 Mar 2017 13:33
Reply 


If you have the room, ground mount has a few advantages. You can set it to the exact angle for optimum exposure. And, it does not have the problems with roof-top. Eventually you will need to service the roof, and the panels are in the way. Not a big deal- they just need to be taken down and re-installed, but it adds labor costs. But with a metal roof it will be decades before the roof needs replacing. 50/50

itsals1
Member
# Posted: 9 Mar 2017 21:12 - Edited by: itsals1
Reply 


Wow, Thank you!

The ground mount would be stationary, I refuse to use a tracker. I've seen 1 crumble to the ground do to high winds,even with a concrete sonatube structure. The math tells me that 26*-30* will produce more power during the summer months because of the longer daylight hours. So I think a 4/12-6/12 pitch roof would be ideal for roof mount.
Any suggestions on solar companies like wholesale solar?
Thank you,
Travis

neckless
Member
# Posted: 10 Mar 2017 05:36
Reply 


FYI ...my freind installed a roof mount on his garadge a few yeas ago...i think i see him up on a ladder almost very day sweeping the snow off...

Atlincabin
Member
# Posted: 10 Mar 2017 09:45
Reply 


I got my setup for my cabin from Wholesale Solar. Very nice folks, easy to work with, accessible for questions via email or phone. Highly recommend them. They have been in business for a long time, so that says something about them.

creeky
Member
# Posted: 10 Mar 2017 16:18
Reply 


In our area there are hundreds of trackers. Never seen one fail like that.

The advantage to roof mount is you get a building and a solar rack in one. Sweeping is up to you. 😊

I've been recommended to renvu in the us. Might want to check their prices.

itsals1
Member
# Posted: 10 Mar 2017 20:23 - Edited by: itsals1
Reply 


Talked with the installer today. He highly recommend that we use the IronRidge ground mount (3" pipe). They bore 18" x48" holes and concrete them in the ground. He mentioned that they have yet to do a roof mount system because all there installs have been 10kw or larger. Due to snow load and the dead load that solar panels add,most existing roofs are not engineered for this. Even with us building a new structure the added trusses and constuction materials is more than the ground mount racking. Then there's the what if a optimizer goes bad,now I need to climb on the roof and remove the panel or panels to replace that. Thank you for replies, please keep your opions coming. You all are very helpful.
Travis

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