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Posts: 95
Reply with quote  #11 
Back to doing a little more work on the installation. The house I live in has lots of roof space, but for the time being I'm leaving most of it alone. Since I only have a small number of panels to install I decided at least for this winter to place them above the patio in the back yard. However the patio only has about a 9 degree slope. it is no longer level and one of my landlord's requirements was no holes in the roof itself. Soooo...I decided to attach brackets to each end of the patios roof, build a frame to sit on the brackets, build up the height above the brackets so that the frame would both set level, plumb and above the roof all the way across the patio. Also because of the amount of weight that will be added and the fact that the joists which the framework brackets would be attached to are essentially only attached by toed in nails I thought I should add a few braces underneath the roof to help stiffen up the ends.

Mo Underbracing.jpg 
After determining where the side mounting brackets would be positioned I installed some 2x6 cross bracing under the roof between the two end joists.


Built some trusses out of 4x4 bases and 2x4 diagonals. They are around 32 degree angles.


Then painted them.

4x4 mount(Small).jpg  2x4 mount.jpg 
Installed the brackets on the ends. Used almost all 3/8" hardware to mount everything. The brackets have bolts going through the joists to hold them in place. On one side I used a 4x4 "spacer" and on the other side a 2x4 so that the frame would end up being level across the patio when installed. The spacers are held to the brackets with 3/8" lag bolts.

Completed Frame.jpg

Ran two 16 foot long 2x4's across the back and a few more short ones between the trusses down low for stability. Oh, the end trusses were attached to the spacers with eight 7 or 8 inch 3/8" shoulder bolts as needed. So as it stands now the framework is 15 feet across and solid as a rock. If you look closely you can see that the two middle trusses are both off the roof just a bit. The one on the right needed a couple 3/4"spacers and the left one used inch and a half. They are simply sitting under the frame but covered with some of that plastic undercoat type stuff so they don't rot and should stick to both the frame and the roof. The strings in the picture were to verify alignment. They are sagging because we got a ton of rain earlier today. So now I need to get some strut to attach the panels to. I did pick up a Victron 250/100 charge controller but still haven't picked an inverter yet. Also this will be a fully external install. All batteries and electronics will be outside the house so I am searching for some reasonably priced electrical enclosures.



Posts: 95
Reply with quote  #12 
Panels installed (Small).jpg 

Hey! I'm back. Well screwed around taking my time on this for months and finally got it more or less done. Installed the panels I think back in December. There are 8- 310 watt panels so if needed they could provide around 2500 watts of power max.

Battery box ugly.jpg

Found this steel box to house my batteries on CL for $30. It was kind of beat up with a fair amount of surface rust but none too deep. Sooo..

Battery box pretty.jpg    

A $10 can of Rustoleum and she's good as new.

Bare batteries in box.jpg

The Volt batteries fit nicely and leave enough room for cabling and circuit breakers. Eventually I'll 
strap those batteries down.
Breakers wired.jpg 
And now they are wired up. Each of the 8 packs has its own breaker so that it is easier to remove individual packs if necessary. The two larger cables on the right of the breakers go to the charge controller and the inverter in the control box.

Control box Naked.jpg 

  Well all those wires had to go somewhere and here it is before the wire run. The charge controller is a Victron that can handle up to 5800 watts with a 48 volt output to match up the the 48 volt Chevy Volt battery packs. I over sized it on purpose because next year I expect to double the size of the system.

Control box Terminated.jpg 

Here is what it looks like all wired up. The smaller wires coming in from the top left are ten gauge from the panels and they get combined through the three breakers on the left. Max voltage can be a bit over 200 v. The larger 2 gauge wires on the lower left go to and from the battery pack. The breaker on the right of the din rail is the shutoff coming from the batteries going to the inverter. This is just a cheap $300/3000 watt inverter for the time being because that is all I really need at this time. 
Cable run.jpg 

The cable run between the battery box and the control box was really simple. Inch and a quarter pvc conduit and a couple LB's. However that was a pretty tight fit so next time I go up to at least inch and a half.

Conduit run.jpg 
For the first few days of testing I just ran an extension cord into the house which can be seen coming out the left side of the control box. Oh yeah,the control box was free too so no cost lost there. Except I do have to cut some wood for a front door for it. For a more permanent wire run into the house I used half inch emt shown coming out of the right side of the box. That goes into a pre-existing opening that I remove the outlet from and then placed a new outlet inside the house. We have pretty low electrical usage here at the house so I am only powering the high use appliances. In our case that would be the refrigerator(1.5-2.0 kwh/day), my television(.5 to 1 kwh/day) and the same with my room mates tv. Additionally I have begun doing all electrical cooking at the inverter location(coffee, blender, rotisserie, and veggie steamer. Our normal usage is between 7 and 9 kwh/day. Now that the solar is in use our utility usage is between 3 and 6 kwh/day.

If I hadn't mentioned it, this is a stealth off grid system. So, not feeding into the utility grid at all. I know that many people think that we should be grid tied so we can sell our excess power to the local utility but I am a fan of Jack Rickard (video link later) in this respect. I don't want to sell my energy to the power company at a rate they get to dictate. Our bill will be low enough that for the most part it will be below the minimum charge per month of around $20. For $20 per month I don't mind using the power company as an energy backup. Also in California the utilities have to give us some sort of climate change credit twice a year that will somewhat negate that $20/month fee. Our last climate credit was $53 and the one before that was around $70. It's due again in October.

Right now I probably have around $4000 into the build and by the time I get done it will likely be double that. But I expect to have 50 kwh of battery pack and a total of about 5 kw of panels. Then what I'll do is install a 200 amp manual transfer switch so I can turn off the utility power feed when I want. My guess is I wouldn't need them more than a few time a year. Then again, I might just get a backup generator and go off grid completely. Back to economics. I know I will never get the cash back that I have put into this thing. I simply manage our energy usage well enough that our bills here are extremely low in the first place. But everybody needs a hobby and one of my hobbies is taking money away from the utility companies. Hell, I've spent more money on my bicycles in the past ten years than I will have total on the solar install by the time I'm done. How much do you guys spend on your other hobbies?


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Posts: 2,990
Reply with quote  #13 
Nice setup!

Solar is like the wind. It may be free, but putting it to work isn't!
Willie, Tampa Bay
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