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Thread: My workshop solar project

  1. #1
    Join Date
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    My workshop solar project

    I bought a 7.2 kw grid tied system to install on the shop. In order to make the numbers work I have done all the roof work myself. I had banked some work hours with the friends pictured so no labor costs other than the electrician who is coming in this week. I was in the solar business back in the 70ís, 80ís. The Iron Ridge Rack system was excellent other than the fact that I had to punch 84 holes on my perfectly good 5 yr old roof. I had the guys lined up to hit this and get it done in a couple days and then we all stayed home, so On that 8/12 I did the racking myself. At 71 it like to kick my butt, but short days and no hurry. Slow and steady wins the race. Life is a humbling experienceB9428CAF-9781-4B63-8D4D-F25C370A6591.jpg90B1B84A-FDB0-48B3-85BD-AEE035A6EE01.jpg16B4CEFE-9FE9-41E5-A434-9AE9AA4010CD.jpgF78D3AC5-DA4A-416F-9AD4-7EB125AED128.jpg

  2. #2
    I donít understand how you use that kind of electricity. Donít solar panels generate DC voltage? What are people running with these things?

  3. #3
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    Looks great, Jack! At least you have a nice rectangular roof to make it slightly easier.

  4. #4
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    Quote Originally Posted by Ben Helmich View Post
    I don’t understand how you use that kind of electricity. Don’t solar panels generate DC voltage? What are people running with these things?

    Google 'inverter'.
    "The Danish government believes that if we train 5,000 designers, and produce
    one Hans Wegner, the money is very well spent." - Ole Gjerlov-Knudsen

  5. #5
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    Ben, I am using Enphase 7+ Microinverters. They have excellent training videos on their site. Each panel has its own MI, so 24 panels, 24 MI. That helps in shading output. Without the micro inverters if one panel in a string got shaded it would cut off output to the rest of the string. With them, if 6 panels are getting shaded I am still producing with the other 18. Also the MI's mount to the rack below the panel. Roof wiring is quite literally snap, snap, snap and discreet connectors so you can't miss...well, as long as you hear the "snap" on connection. Yes, the panels produce DC current, but the MI's convert to AC on the roof. All my in-building wiring can be run in romex. As this is a "grid tied" system I am only pushing power back to PG&E, but other than the standard hook-up charge I will have no electric bill.

  6. #6
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    Jack, can you run everything in your shop off solar after this project?

  7. #7
    7.2KW. So that would give you 30A @240v or 58A @ 125v? Is that right? Sitting here in my chair using my computer next to a window unit I'm pretty sure I'm using less than that right now. That is cool! Let us know how it works out. I think my shop would pull maybe 50A at full load: table saw, window unit, dust collector, lights, chargers for batteries and laptop. And you're unlikely to pull full load often with a saw. Would you use batteries to store any, or just pull off the grid when the sun ain't shining?

  8. #8
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    Iím guessing the excess power goes back to the grid and his electrical bill goes down, or negative.

    Very nicely done Jack, you should be proud!

  9. #9
    Join Date
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    Nice job. Am envious. We don't get the solar days to make a system very efficient here. I would be all over it if it made economic sense.
    Regards,

    Kris

  10. #10
    Join Date
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    Quote Originally Posted by Matt Day View Post
    I’m guessing the excess power goes back to the grid and his electrical bill goes down, or negative.

    Very nicely done Jack, you should be proud!
    Yes that is correct, although what state you are in matters tremendously. In Florida, that's the case. In California, with different rates at different times of day, it's more complicated.

    Very nice job, Jack.
    You're like the door closing button on an elevator. Comforting but not necessarily effective.

    After cancellations this year, I have enough frequent flyer miles to orbit the sun.

  11. #11
    Join Date
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    I have a 30kWh system on my roof in Florida. In my case, the my roof height starts at 45', so there was no way I would ever consider going up on the roof. I worried about the installers every second they were up there.

    I ran a surplus last year, so Duke Energy actually paid me for electricity, although the monthly billing charges of $10.25 eat into that, and they only pay you $0.0325/Kwh for the surplus, and charge you $0.13 for electricity you use, so the system is totally rigged in their favor.

    That being said, I love having my home and workshop being solar powered. It provides enough electricity for me to run 5HP machines and 5HP cyclone, lights, etc...

    IMG_2370.jpg
    You're like the door closing button on an elevator. Comforting but not necessarily effective.

    After cancellations this year, I have enough frequent flyer miles to orbit the sun.

  12. #12
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    Quote Originally Posted by Jack Frederick View Post
    Ben, I am using Enphase 7+ Microinverters. They have excellent training videos on their site. Each panel has its own MI, so 24 panels, 24 MI. That helps in shading output. Without the micro inverters if one panel in a string got shaded it would cut off output to the rest of the string. With them, if 6 panels are getting shaded I am still producing with the other 18. Also the MI's mount to the rack below the panel. Roof wiring is quite literally snap, snap, snap and discreet connectors so you can't miss...well, as long as you hear the "snap" on connection. Yes, the panels produce DC current, but the MI's convert to AC on the roof. All my in-building wiring can be run in romex. As this is a "grid tied" system I am only pushing power back to PG&E, but other than the standard hook-up charge I will have no electric bill.
    I assume this means he doesn't use any power generated by his own panels.

  13. #13
    Join Date
    Jan 2010
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    Quote Originally Posted by Keith Outten View Post
    I assume this means he doesn't use any power generated by his own panels.
    I just wrote a long reply, which vanished.

    Basically, you have to think of this as net energy, measured by a net meter.

    Let's say that your array is producing 24Kwh at noon. Your house is using 15Kwh. So your array sends 9 Kwh to the grid, and you use 15Kwh that you are producing. The meter runs forwards or backwards at any time if you are producing a surplus, or in the opposite case, using more than you are producing (Actually, my meter shows 2 numbers - what my array sends to the grid, and what I used from the grid.)

    Unless this works totally differently in California. Lots of things are "different" in California,

    Clear as mud?
    You're like the door closing button on an elevator. Comforting but not necessarily effective.

    After cancellations this year, I have enough frequent flyer miles to orbit the sun.

  14. #14
    Haven't watched co-workers drown, but as a nineteen year old, watched the guy working with me get electrocuted. Happened in an instant. He and I flipped a coin to see which would be doing which job. I LOST the coin flip!

  15. #15
    Join Date
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    El Dorado Hills, CA, USA
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    Quote Originally Posted by Alan Lightstone View Post
    Let's say that your array is producing 24Kwh at noon. Your house is using 15Kwh. So your array sends 9 Kwh to the grid, and you use 15Kwh that you are producing. The meter runs forwards or backwards at any time if you are producing a surplus, or in the opposite case, using more than you are producing (Actually, my meter shows 2 numbers - what my array sends to the grid, and what I used from the grid.)

    Unless this works totally differently in California. Lots of things are "different" in California,
    Net, you are right for California too. But I think of it a different way. When the grid is down, our solar panels cannot be used to power our house. So the way I look at it is our panels send everything they generate to the grid, and we draw back what we need, the same way we would with no panels. And then the electric co figures out the net difference for your bill. I have no idea whether that's more, or less, technically accurate than your description, but the net result is the same

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