What are you generating?

nvyseal
nvyseal Solar Expert Posts: 108 ✭✭✭✭
in General Solar Power Topics #1
The last few days my 4.7 KW system has been generating 37 kWh a day. Nice to see the meter spinning back further every day.

Now if i just had that natural gas well solarvic has ;)
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  • a0128958
    a0128958 Solar Expert Posts: 316 ✭✭✭
    #2
    Re: What are you generating?
    nvyseal wrote: »
    The last few days my 4.7 KW system has been generating 37 kWh a day. ...

    Wow. If you assume you have a system like SG, where your derating factor is 90% to cover all losses, including DC to AC conversion, wiring, output variation panel to panel, imperfect azimuth/tilt/shade, and temperature of your panels, that's 8.7 hours of insolation (8.7 sun hours).

    If you instead assume the default 77% factor used by PVWatts, then it's even more insolation, at 10.2.

    That sure seems to be a lot of sun hitting your panels!

    Best regards,

    Bill
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  • russ
    russ Solar Expert Posts: 593 ✭✭
    #3
    Re: What are you generating?

    Where are you located?
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  • nvyseal
    nvyseal Solar Expert Posts: 108 ✭✭✭✭
    #4
    Re: What are you generating?
    a0128958 wrote: »
    Wow. If you assume you have a system like SG, where your derating factor is 90% to cover all losses, including DC to AC conversion, wiring, output variation panel to panel, imperfect azimuth/tilt/shade, and temperature of your panels, that's 8.7 hours of insolation (8.7 sun hours).

    If you instead assume the default 77% factor used by PVWatts, then it's even more insolation, at 10.2.

    That sure seems to be a lot of sun hitting your panels!

    Best regards,

    Bill

    Hi Bill,
    I didn't mean for this thread to be about my system, but more of a reference on what a size of a system can produce, and trust me, there are days that my system does not perform as well (cloudy or extremely hot). I do get a fair amount of sunlight. My inverter says its operating about 10+ hours a day. Panels are facing south on a flat roof house with a 15 degree tilt with very little shade from about 10:00am to 4:00pm. It's 8:00am right now, generating 1000w. The system won't shut down until about 6:30pm. DST
    russ wrote: »
    Where are you located?

    Hi Russ
    Southern California, Rancho Cucamonga (Alta Loma)
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  • mikeo
    mikeo Solar Expert Posts: 386 ✭✭✭
    #5
    Re: What are you generating?
    The last few days my 4.7 KW system has been generating 37 kWh a day
    Well here in the Mountains of Arkansas, my little 1800 watt grid tied hybrid system is generating around 10 kw each day. This is the time of year where the system will peak on perfect days, I generated 11kw on one day last year. That's nice, but then there's all those days I don't even generate 4 kw. The combination of cool weather, clear skies, low humidity and higher sun angle are all coming together. Later, the weather will get hot, humidity will be high and summer rates will drop to 7 kw a day on the best days.
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  • drees
    drees Solar Expert Posts: 482 ✭✭✭
    #6
    Re: What are you generating?

    I'm doing very close to 20 kWh on clear sunny days right now. 3.24 kW DC system in San Diego. Did 19 kWh today with clouds coming in right at 4pm.

    Panels are mounted nearly flat. As long as the sun hasn't gone down or up, the system will be generating some small amount of power (see link in my sig), so with current sunrise/sunset of 6:30/7:15 the inverters wake up/shutdown about 5-10 minutes after/before those times.

    I'm impressed by nvyseals' numbers - he's producing 85% more energy than me with a system that's only 45% larger. DC-watt for watt, that's about 27-28% better. Can panels tilted south 15* instead of mounted flat improve performance by that much? I thought my numbers were already pretty good comparing to PVwatts output.

    nvyseal - what's your peak output on a clear sunny day? Mine is currently 2.6-2.7 kW. I'd have to guess you are actually hitting your nameplate rating of 4.7 kW which is impressive given that 15* is still angled too flat for this time of year and that it has been in the 80*s the past couple days.

    At 8am I'm currently producing between 650-750 watts which is on scale with your output at that time... I have a bit of a disadvantage as my panels are actually tilted West 3-5* or so.
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  • RandomJoe
    RandomJoe Solar Expert Posts: 472 ✭✭✭
    #7
    Re: What are you generating?

    I have 1080W STC on a battery-based system. I don't run anywhere near enough stuff to keep the system occupied fulltime, so the inverter switches loads over to battery around midnight. This draws the batteries down about 20% to give the panels something to do. I still hit absorb then float handily before the end of the day so "lose" some potential production capacity.

    Right now when the days are nice and clear I'm hitting around 4.5kWh/day. Of course, we are having uncommonly cloudy weather this year so...! :roll: Today's reading is the best so far, 4.77kWh.
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  • LucMan
    LucMan Solar Expert Posts: 223 ✭✭✭
    #8
    Re: What are you generating?

    5.2 KW grid tie - 31 degree tilt= 23-27 KWH on sunny days.
    In the last month the best single day was 32kwh.
    Panels get full sun about 6 hrs. per day this time of year.
    Today no clouds 52 degrees 30 kwh, peak output 4617w
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  • nvyseal
    nvyseal Solar Expert Posts: 108 ✭✭✭✭
    #9
    Re: What are you generating?
    drees wrote: »

    nvyseal - what's your peak output on a clear sunny day? Mine is currently 2.6-2.7 kW. I'd have to guess you are actually hitting your nameplate rating of 4.7 kW which is impressive given that 15* is still angled too flat for this time of year and that it has been in the 80*s the past couple days..

    im often pushing way over the rating, especially when a cloud passes. today even with hazy sun i've already generated 10kWh (11:14am PST) and holding steady at 4598w. max was 5373w.
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  • drees
    drees Solar Expert Posts: 482 ✭✭✭
    #10
    Re: What are you generating?
    nvyseal wrote: »
    im often pushing way over the rating, especially when a cloud passes. today even with hazy sun i've already generated 10kWh (11:14am PST) and holding steady at 4598w. max was 5373w.
    OK, you're going to have to give us full details on your system so we can learn your secrets. :D To be generating 4.6 kW AC out of a 4.7 kW DC system at 11:15am is impressive - should conditions remain similar you should peak another 10% higher today or over 5 kW when the sun is right overhead at 12:55pm.

    What's your normal peak on a clear day? (For example, for the 6th, 7th, 8th this week).

    The sun is at it's peak (use this tool to calculate the sun's elevation for your location) right around 12:55pm pm, so you should be seeing your peak then with the panels angled south. The current elevation of the sun at that time is about 62.6 degrees, meaning that ideally the panels would be tilted up 27.4 degrees this time of year.

    During summer solstice (June 21 this year), the sun's elevation will be 79* so your output should be even higher then if the temperatures/wind are similar.
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  • nvyseal
    nvyseal Solar Expert Posts: 108 ✭✭✭✭
    #11
    Re: What are you generating?

    Hi drees

    Lets see if these numbers from my inverter will help you out. Just taken. Sorry if the pics are a bit dark, its from my garage.
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  • solarvic
    solarvic Solar Expert Posts: 1,071 ✭✭✭✭
    #12
    Re: What are you generating?

    The display looks the same as my fronius inverters. My highest output so far in 1 day has been 28 kw. 635 kw since March 3 as recorded by my personal power meter. If I would get rid of the electric waterheater and electric dryer I would have a surplus. S:Dlarvic
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  • nvyseal
    nvyseal Solar Expert Posts: 108 ✭✭✭✭
    #13
    Re: What are you generating?
    solarvic wrote: »
    The display looks the same as my fronius inverters.

    Yup! Good Eye solarvic! the infamous fronius 5100 :D

    Today, with clouds i didnt do so well, only 36kWh
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  • Brock
    Brock Solar Expert Posts: 639 ✭✭✭✭
    #14
    Re: What are you generating?

    Yesterday was a good day, sunny and cooler, we are at 44* north.

    1.8kw system generated 11.8kwh

    I keep thinking, what is the best way to put all our systems in to comparable numbers. Would it be array wattage devided by watt hours out?
    3kw solar PV, 4 LiFePO4 100a, xw 6048, Honda eu2000i, iota DLS-54-13, Tesla 3, Leaf, Volt, 4 ton horizontal geothermal, grid tied - Green Bay, WI
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #15
    Re: What are you generating?

    (And all the 'off-gridders' reading this are wondering: "What on Earth do these guys need all that power for?!" :p )
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #16
    Re: What are you generating?

    coot, if you met my wife you'd know. she, like so many others, takes it all for granted and then she gets mad at the electric company when she sees the bill's $ amount. it's all their fault, not hers, don't you know?:cry:
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  • solarvic
    solarvic Solar Expert Posts: 1,071 ✭✭✭✭
    #17
    Re: What are you generating?
    nvyseal wrote: »
    Yup! Good Eye solarvic! the infamous fronius 5100 :D

    Today, with clouds i didnt do so well, only 36kWh
    Nvyseal. Don,t look like you are doing to bad with the Fronuis. I have 2 smaller ones since I didn,t buy my solar panels all at the same time. the first ones went out of production so had to get something different. the second ones I got are out of production and
    i could use 2 more if I could find them. Thinking f putting a couple mitsubushis with the 12 sharps as I think that the 2 kyocera I have with them pulled the power output down to the lower output output. I only get 1 volt more with the sharp array and it should be higher. the most I get so far is 28 kw. The ig 2000 was putting out its limit. it is rated 1800w and I was seeing about 1950 w today. 2000w is the limit. The ig 3000 wasn,t outputting any more. S:Dlarvic
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  • nvyseal
    nvyseal Solar Expert Posts: 108 ✭✭✭✭
    #18
    Re: What are you generating?
    Cariboocoot wrote: »
    (And all the 'off-gridders' reading this are wondering: "What on Earth do these guys need all that power for?!" :p )

    HAHA! I ask myself that question also. This house could never ever go off grid. I can go running around unplugging things and turning off lights and TV's but it seems for every 1 thing i unplug, i come back only to find 2 things plugged in. Its like trying to keep a black car clean.

    I just wish there was some way all the members at wind-sun as a collective could add our kWh together for a year to show what a small community can do to offset its carbon footprint. That in itself would be great PR for solar
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #19
    Re: What are you generating?

    There's no reason why a utility-powered house needs to use any more electric than a remote cabin. That's less than 3 kW/hrs per day (far, far less if you're Icarus).

    But if the power is there, you use it.
    Until one day it isn't there anymore.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #20
    Re: What are you generating?

    i just had to be on the semi rant about my other half and i soon went down to investigate a noise and saw her with her little quartz heater on and she said she got cold. mind you it's 50 degrees f outside as i type this and she left the window wide open. pulling hair out including the gray ones.:cry::cry::cry::cry:
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #21
    Re: What are you generating?
    niel wrote: »
    i just had to be on the semi rant about my other half and i soon went down to investigate a noise and saw her with her little quartz heater on and she said she got cold. mind you it's 50 degrees f outside as i type this and she left the window wide open. pulling hair out including the gray ones.:cry::cry::cry::cry:

    We had a daughter who opened the window for fresh air and cranked the heat up to stay warm. This in a house with a fresh air heat exchanger.

    Maybe we could have a little forum contest; see who can reduce their power consumption the most in 30 days. The winner gets a lower electric bill!

    Seriously; anybody really spin their meter backward and achieve a 'negative' bill?

    I'd put grid-tie in at the new place (ideal orientation) but BC Hydro doesn't pay enough to justify it. Even though they just hiked the rates. Why, we're now paying 1/3 the national average instead of 1/4! It's an outrage! :p
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #22
    Re: What are you generating?

    i can't afford to send her on vacation for a month to have a chance to win it.;):D:p
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  • nvyseal
    nvyseal Solar Expert Posts: 108 ✭✭✭✭
    #23
    Re: What are you generating?

    I thought it would be a good idea to show my GF these last few posts to get her to realize energy conservation and that folks can live on just 3kWh a day. After she asked what we used, and i told her, she went off... "even the cavedude on GEICO uses more..." "tell those guys im not giving up my sub-zero!" "If you want to start saving energy, you can sleep on the couch"...

    I'm sorry, the hair dryer, curling iron, and the electric toothbrush... and the sub zero has to stay, for my sake!
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  • dsp3930
    dsp3930 Solar Expert Posts: 66 ✭✭✭✭
    #24
    Re: What are you generating?

    Yesterday was the best day I have had since I installed my first three Sharp 224w ND-224UC1 panels -- 4.7 kw generated. (peak at 647w) I have 9 more panels waiting to go in next month. With those installed - I would have been at about 18.8 kw for the day.


    Told my wife about this chain. She laughed and said she knows she is bad about the TVs with the kids. It seems that our kids like to go from room to room watching several different shows. She then noted I was also bad about leaving our bedroom and closet lights on occasionally. I prepared to duck ... as I pointed out that the bedroom had three 14w CFL lights while the TVs pull a combined 300-400w. She looked at me, was ready to say something, then smiled and walked off.

    I guess I feel lucky though as she is on board with just about any energy saving measures we can do. She has been great dealing with me obsessing about the best way to do something or listening to me describe some minutia of some plan to her.
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  • a0128958
    a0128958 Solar Expert Posts: 316 ✭✭✭
    #25
    Re: What are you generating?
    Brock wrote: »
    ... I keep thinking, what is the best way to put all our systems in to comparable numbers. Would it be array wattage divided by watt hours out?

    I think the performance item to compare is how efficient one's system is. I.e, SG's at 90%. I think I'm at around 65%. And when nvyseal started this thread I wondered just how efficient his system is (certainly appears incredibly so). And look at the impressive performance from Mikeo (and his system is hybrid).

    What's needed is the day's actual insolation to enable 'apples-to-apples' comparison. I looked around for awhile to see if somewhere there's published daily insolation. The best I could find is here.

    This map shows that approximately my insolation for Apr. 9th was 6.9 sun-hours (divide by 3.6 to convert measurement units - i.e., 25 / 3.6 = 6.9). Noting I too had a record day for Apr. 9th, at 42.5 kWh, this would then say my (8.1 KW) system's performance is
    42.5 kWh / 6.9 sun-hrs / 8.1 KW = 76%

    That seems about right for as perfect as the day was.

    nvyseal is in Southern CA. From the same map Apr. 9th insolation was approximately 6.9 sun-hrs. His efficiency would thus be
    37 kWh / 6.9 sun-hrs / 4.7 KW = 114%
    Obviously a DC-to-AC Derating Factor of 114% doesn't make sense, and hence my guess is his insolation was in fact much higher than 6.9. Still, his system must be incredibly tuned to obtain 'every last drop' of kWh harvest.

    Mikeo is in the mountains of AK. From my interpretation of the insolation map, his approx insolation on Apr. 9th was 6.4 sun-hours. His efficiency would thus be
    10 kWh / 6.4 sun-hrs / 1.8 KW = 87%

    This seems reasonable, noting that although Mikeo's system is hybrid it's probably finely tuned for maximum performance.

    My conclusion here is that a key piece of information needed to compare system performance is actual insolation. Knowing this, accurate performance or efficiency (actually overall DC-to-AC Derating Factor) can be computed to enable comparison.

    If anyone knows of a better source for actual daily insolation numbers as a function of location, please comment. PVWatts won't work here because it presents a monthly historical average.

    Best regards,

    Bill
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #26
    Re: What are you generating?

    Actually, PVWatts has an "Output Hourly Performance Data" button too... It uses the data from a "meteorologically typical" day.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • a0128958
    a0128958 Solar Expert Posts: 316 ✭✭✭
    #27
    Re: What are you generating?
    BB. wrote: »
    Actually, PVWatts has an "Output Hourly Performance Data" button too... It uses the data from a "meteorologically typical" day.

    Yes, PVWatts uses 'meteorlogically typcial' data - i.e., it's an average. For the purposes of the discussion here, I think what's needed is the actual insolation (and for the entire day).

    I thought this would be easy to find, but, found out otherwise. I was surprised that I couldn't look up somewhere what the actual insolation was for Apr. 9th for my ZIP or lat/long.

    It's easier to see now why some people have their own pyrometers (and producing insolation for the day by integrating each solar irradiance sample). Daily insolation increasingly to me appears to be the key number needed to carefully affirm solar PV performance, and to enable comparison of system performance on an 'apples to apples' basis.

    Best regards,

    Bill
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  • dsp3930
    dsp3930 Solar Expert Posts: 66 ✭✭✭✭
    #28
    Re: What are you generating?

    I have a 672 watt array. (3 x Sharp ND-224UC1)
    I output about 4700 watt hours on April 9th. (according to my Xantrex SCC)
    This equates to roughly 6.99 hours at 100% of PV panel rated production.

    Sunrise is roughly 7AM. (No trees to the east)
    Sunset was roughly 8PM. (Trees start blocking sun at 6:45PM)

    I live in the SW corner of Lake Erie ESE of Toledo, OH.
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  • russ
    russ Solar Expert Posts: 593 ✭✭
    #29
    Re: What are you generating?

    A Davis weather station with solar meter?
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  • mikeo
    mikeo Solar Expert Posts: 386 ✭✭✭
    #30
    Re: What are you generating?
    A Davis weather station with solar meter?
    Speaking of which, here is a graph of the solar insolation on Apr 9th for my system.

    http://forum.solar-electric.com/attachment.php?attachmentid=1096&stc=1&d=1271000322
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #31
    Re: What are you generating?

    Interesting thread, wife comments well understood, mid morning this houses idle load is about 1000 watts. Fortunately she is pretty green minded and pushes high load activities into our off Peak on the TOU rates. This year we will replace the fridge & the deep freeze with energy star models, The deep freeze I suspect is the worst, very old.

    Attached is a graph of the last week, and my last months data lines up pretty close to the utility. My peak day this week was April 7 @ 63.305kWh. The Green Bars are the solar generation, the Red bars are the load and the blue bars are the net for the day.

    It got to be about 90F in Phoenix yesterday so the load was up for AC part of the late afternoon, and early evening yesterday the 10th. It is now 8:45 AM and the data for the 11th is moving in the right direction.

    As for why so much power? Swimming pool, AC units (2), We currently have about 1,800kWh stored in the utility this year for later use on our summer usage. we hope to top that out at around 4,000 kWh before June when the draw is going to be the other direction to power those AC units. Also to that end we are adding in another 2160 of panels to top out the two 6000 watt inverters.

    Live system is online here:
    http://phx-solar.dyndns.org:8081/Footprints.html
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