15 kw net metering array

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  • bcroe
    replied
    Losses

    Originally posted by Bobodude
    Nice system Bcroe. My only comment is on the transmission cable from the panels to the out building. If I understand you right it's 600' with #4 cu? Wow, that is nearing a wopping 8.27 % voltage loss at full load! I know it was free but that will be a loss forever! I used 4/0 aluminum for my 70' run from panels to inverter. And it was free too. Wish you the best of luck my friend.
    Using oversized wire is great, esp if you get a good deal. But not having
    to dig the trench or lay the wire is a big trade off. All the trade offs were
    known at the beginning; if I bring in more energy than I need, it will be
    wasted on a Tier 2 grid tie. The actual resistance of the 4 gauge loop
    was measured in advance with a Kelvin connection.

    Actually the LOOP is 600', 300' each way. 255V @59A gives me a loss
    of 9V across the 0.15 ohms, or 3.5%. Since that only occurs at peak
    power, its a good trade off verses digging up and replacing all that wire.
    Keep in mind there are DC copper losses of 1.4% from the panels and
    inverter losses of 4.5%. So trying to beat 1% out of the total 9% is
    really into diminishing returns. Copper loss % drop linearly as solar
    energy decreases; inverter loses stay in the area of 4.5%. In the long
    run, if I cancel out my house energy bills, the losses don't matter. I
    still need to install the additional R50 insulation this fall, to adjust the
    consumption end.

    Still bringing in 90+ KWH (inverter output) every sunny day this month.
    Bruce Roe

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  • Bobodude
    replied
    Nice system Bcroe. My only comment is on the transmission cable from the panels to the out building. If I understand you right it's 600' with #4 cu? Wow, that is nearing a wopping 8.27 % voltage loss at full load! I know it was free but that will be a loss forever! I used 4/0 aluminum for my 70' run from panels to inverter. And it was free too. Wish you the best of luck my friend.

    Leave a comment:


  • bcroe
    replied
    15 KW Solar Array Operational Report

    After some weeks of operation, i am getting some
    actual numbers. Ultimately the goal is 23,000 KWH
    a year collected, or 63 KWH a day. In recent days,
    with serious clouds every afternoon, its running some
    15% ahead of the goal. Some days 45 KWH, some
    near 100 KWH. I missed out on the most optimum days
    around the beginning of summer, which should have
    done quite a bit better. Esp, June & July due to the
    AUTHORITIES failing to get the NET METER installed
    when agreed. Will have to estimate that production,
    measure it for real next year. I know, it will drop in winter.

    At this season it produces energy some 14 hours a day.
    The extreme tails give out some hundreds of watts, when
    the sun isn't directly hitting the panels. Soon as there is
    direct sun, it does kilowatts. It takes 16 KW solar DC to
    produce the inverter max of 15 KW AC, after DC copper and
    inverter losses. With 18 KW of panels, there is some
    clipping anywhere near solar noon, if there isn't a cloud
    in the way.

    If the sun is completely blocked, output could be 5% to
    15%, depending on just how dark it is. That includes rain.

    Generally, everything was planned over some months, to
    fit the existing space, facilities & needs as much as
    possible. All the operating parameters so far are pretty much
    where they were expected to be.

    With the panels being over 500' from the house and the NET
    METER, transmission losses are part of the design. A 600'
    loop of 4 gauge carrying 250 volt at 60 amps AC (15 KW)
    can exceed 3% loss. I knew that, but it was already in place
    for free, and no where near overloaded. However the line
    voltage here is rather high, 120V/240V all the time. Add 9V
    drop in my loop, and the inverters are seeing 250V at peak.
    The worry is, they are nominally programmed to trip out at
    264V (hasn't happened yet).

    My question is, what to do if they start doing high line voltage
    trip out? It won't hurt the inverters; they are designed to
    operate up to 277V nominal. Perhaps the trip point could
    be programmed a bit higher; anybody know how adjust a
    Fronius?

    Failing that, another way to get some margin is lower the
    voltage to the inverters a bit with an AUTOTRANSFORMER.
    Just a 5 or 10 volt shift down (at the full 60A) ought to be
    enough. Pretty clumsy way, just in case all else fails.

    It will take a couple years to run this science project out.

    Bruce Roe

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  • bcroe
    replied
    Mowing

    Originally posted by bonaire
    Bruce, three acres is a lot, I've got about 2 to mow. About 2 gallons.
    Here's an upcoming company with electric mowers using Li-ion.
    http://www.meangreenproducts.com/products.html
    Bonaire,
    Its 5 acres, but only about 4 have grass to mow. I don't think there is money left
    to buy a powerful electric mower. 54" cut sometimes takes all of the 27 hp to get
    through. But at 9 mph, can get done in 2 hours, my neighbor calls it "marathon
    mowing". The same AWD rig blows snow in winter, an essential thing in the
    country.

    Bruce Roe

    Leave a comment:


  • bonaire
    replied
    Bruce, three acres is a lot, I've got about 2 to mow. About 2 gallons.

    Here's an upcoming company with electric mowers using Li-ion.

    Leave a comment:


  • SunEagle
    replied
    Originally posted by bcroe
    Of course it is zoned AG. There are horses on the other side of the fence, but they eat too
    little & leave way too much behind. Then there are the deer....
    It must be tough living out in the country. Wish I could.

    Well if I haven't said it yet your pv system looks real nice and I wish you a lot of luck with it.

    Leave a comment:


  • bcroe
    replied
    Goats

    Originally posted by SunEagle
    Also the wool has more value than the milk. But it is nice that the goats will pick up the trash. Maybe a couple of goats with the herd of sheep is a better combination.
    Of course it is zoned AG. There are horses on the other side of the fence, but they eat too
    little & leave way too much behind. Then there are the deer....

    Leave a comment:


  • green
    replied
    Nice setup Bruce!!! I wish I had that much room to work with. I'm glad you only had to lose 2 trees, we are going to have to cut down 7. They are 60+ foot tall spruce and blue spruce that were hit pretty hard with the drought last summer. The good news is that it opens up my options for a ground array.

    Best of luck to you and thanks for the pic and update.

    Leave a comment:


  • SunEagle
    replied
    Originally posted by Sunking
    No use sheep. Goats will eat everything
    Also the wool has more value than the milk. But it is nice that the goats will pick up the trash. Maybe a couple of goats with the herd of sheep is a better combination.

    Leave a comment:


  • Sunking
    replied
    Originally posted by thastinger
    get yourself some goats for the lawn, then you can use the milk as well.
    No use sheep. Goats will eat everything

    Leave a comment:


  • thastinger
    replied
    get yourself some goats for the lawn, then you can use the milk as well.

    Leave a comment:


  • bcroe
    replied
    Electric Car

    Originally posted by bonaire
    Snow won't be a general issue. And, on snowy days, you have lots of clouds anyway, not as much of an issue. The only day you need them cleared early is a nice sunny day that follows the big snows. You can do a heat pump with propane burner use only when temps are lower.
    Also, check out those oil filled radiant heaters that you can position in the room you are in. Lots of
    ways to warm yourself up with the electric power.

    Consider an electric car now to use the power you are collecting. Volt, leaf, tesla, etc. I'd rather drive on that power than sell it back to the utility. I've got a volt myself and really love driving on electricity.
    There will be some "zone" electric heating next winter, while annual energy numbers are compiled.
    I figure to run the propane furnace blower when a zone comes on; a couple guest rooms are usually closed off for the winter.

    There are days when the car never moves. Trouble is when I do travel, its hundreds of miles, too
    far for current electrics. I suppose a hybrid could cover part of the trip electrically, may look into it
    after this stage is well settled. I have no ideas for the tractor, which uses 3 gallons of gas to mow
    the lawn. Bruce Roe

    Leave a comment:


  • bcroe
    replied
    Seasonal Angle

    Originally posted by bcroe
    thanks, I think the next problem is how to change the angle of the 12 racks,
    one at a time. Don't want snow piling on, need a steep angle. I haven't seen anything
    about how to leverage those support braces, could use some examples. There are some
    extra attachment holes to hook machinery; the vision here is something on the tractor
    to adjust & hold the rack while the braces are changed. Bruce
    This thing really cranks! At 8:20 AM savings time (7:10 sun time) its already delivering
    over 4 KW. Hitting 15 KW peak AC output every day the sun is out.

    A rig to change angle seasonally is on order. Its a cheap DRYWALL HOIST from asia,
    uses a hand crank. The numbers look about right for the job, will need to adapt the
    top to fit the rack holes I drilled. And determine if it should sit on the ground,
    or bolt to the back of the tractor. Bruce Roe

    Leave a comment:


  • SunEagle
    replied
    Originally posted by bonaire
    Ford and Chrysler/Fiat do not want to sell electric cars, it seems. But they have to for California requirements, like Honda. Thing is, they really are less expensive to drive and possibly to own long term. Drove over 90 mile on electricity yesterday in my volt using two charges.

    The ford should go 70 or more miles on a charge. I can get an easy 47-50 miles with a smooth pedal on a warm day with only 10.4kWh usable in the volt out of its 16kWh pack.

    Florida should have more EVs than it does. Cheap electricity and a lot of people with retirement money. Warm weather allows for the EVs to get the best mileage.
    I would jump at the chance to lease the Honda Fit. Right now they are going for $259 / mth no money down and they throw in a 220v charger. The Fit has about an 80 miles distance on a charge.

    So far only in California for now.

    Leave a comment:


  • bonaire
    replied
    Ford and Chrysler/Fiat do not want to sell electric cars, it seems. But they have to for California requirements, like Honda. Thing is, they really are less expensive to drive and possibly to own long term. Drove over 90 mile on electricity yesterday in my volt using two charges.

    The ford should go 70 or more miles on a charge. I can get an easy 47-50 miles with a smooth pedal on a warm day with only 10.4kWh usable in the volt out of its 16kWh pack.

    Florida should have more EVs than it does. Cheap electricity and a lot of people with retirement money. Warm weather allows for the EVs to get the best mileage.

    Leave a comment:

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