3.2 KW Residential install w/Enphase Micro-Inverters

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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #32
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    Re: 3.2 KW Residential install w/Enphase Micro-Inverters

    I'm interested to see, in the course of a day, thru the seasons, what the variation is, moment to moment, of each inverter. If you have a plain simple install, you have not gained anything over a central inverter. If you have trees and shadows, then you do have reason to gloat, as only 1 or 2 panels shut down.
    I want to see the main enphase site, where they are tracking all their inverters, and see what their global install base is doing for reliability.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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  • a0128958
    a0128958 Solar Expert Posts: 316 ✭✭✭
    #33
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    Re: 3.2 KW Residential install w/Enphase Micro-Inverters
    drees wrote: »
    ...Public monitoring site is available here:

    http://enlighten.enphaseenergy.com/public/systems/xM8R3368

    First time I've looked at an Enphase monitoring site for a specific installation. Pretty nice to see all of the detail per panel information. I can see how this would be valuable to design around and/or fix shade situations.

    In case you want to do your own analysis work, i.e., arithmetically crunch some of the numbers to further examine system performance, does Enphase provide to its users a means to download the detail data to your local computer?

    And for the total solar PV output, how do you know how much is exported versus how much is used?

    Many thanks.

    Best regards,

    Bill
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  • drees
    drees Solar Expert Posts: 482 ✭✭✭
    #34
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    Re: 3.2 KW Residential install w/Enphase Micro-Inverters
    a0128958 wrote: »
    I can see how this would be valuable to design around and/or fix shade situations.
    Even without any significant shade issues until late afternoon (last couple hours of the day) I still find it informative.
    a0128958 wrote: »
    In case you want to do your own analysis work, i.e., arithmetically crunch some of the numbers to further examine system performance, does Enphase provide to its users a means to download the detail data to your local computer?
    Yes, you can download data on a per-panel per-day basis.
    a0128958 wrote: »
    And for the total solar PV output, how do you know how much is exported versus how much is used?
    I would need to have a way to monitor total energy consumption - right now I only have my main utility meter.

    To get more detailed data, I would either need to invest in a whole-house monitoring setup (eg TED, or WEL like you). It's something I am considering doing so that I can better track where my energy usage is going.
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #35
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    Re: 3.2 KW Residential install w/Enphase Micro-Inverters
    drees wrote: »

    I would need to have a way to monitor total energy consumption - right now I only have my main utility meter.

    It's something I am considering doing so that I can better track where my energy usage is going.

    For a month, I took meter readings, and compared to inverter output, and spring -fall, I was selling, and winter, I was short, and buying. After a month, I gave up, and just used the monthly bill. Daily was meaningless/overload
    You can read your own meter.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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  • a0128958
    a0128958 Solar Expert Posts: 316 ✭✭✭
    #36
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    Re: 3.2 KW Residential install w/Enphase Micro-Inverters
    drees wrote: »
    ... you can download data on a per-panel per-day basis.

    This is good to know. Thanks.

    Best regards,

    Bill
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #37
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    Re: 3.2 KW Residential install w/Enphase Micro-Inverters

    it would be interesting to verify their figures too as we don't know how accurate they are.
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  • nvyseal
    nvyseal Solar Expert Posts: 108 ✭✭✭✭
    #38
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    Re: 3.2 KW Residential install w/Enphase Micro-Inverters
    mike90045 wrote: »
    For a month, I took meter readings, and compared to inverter output, and spring -fall, I was selling, and winter, I was short, and buying. After a month, I gave up, and just used the monthly bill. Daily was meaningless/overload
    You can read your own meter.

    LOL! I was stupid and did that for my entire first year. i listed the inverter output kWh and the meter (sunrise) beginning and end (sunset) so i could get an idea of how all the seasons would affect my generation. I put it all in google calendar. The good thing is i can kinda figure out what my generation is going to be for a given month now
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  • drees
    drees Solar Expert Posts: 482 ✭✭✭
    #39
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    Re: 3.2 KW Residential install w/Enphase Micro-Inverters

    First week of April performance numbers (and last 2 days of March):
    3/30 14.5 kWh
3/31 14.2 kWh
4/1  19.1 kWh
4/2  19.2 kWh
4/3  17.7 kWh
4/4  17.9 kWh
4/5  14.1 kWh
4/6  20.1 kWh
4/7  19.8 kWh
Tot 156.6 kWh

    3/30-31 were half rain, half cloudy
    4/1-4 were partly cloudy
    5th rained half the day, partly cloudy the other half.
    6th was clear, cool and windy
    7th was clear, a lot warmer and a bit less windy

    So far it looks like I'm exceeding the estimated PVwatts output by about 10% - if this average keeps up should see well over 500 kWh for the April.

    PVwatts estimated output numbers: 
    Month / Solar Radiation (kWh/m2/day) / AC Energy (kWh)
1  	3.04      	 228
2  	3.81      	 263
3  	4.93      	 383
4  	6.00      	 445
5  	6.81      	 520
6  	7.09      	 519
7  	7.07      	 525
8  	6.66      	 492
9  	5.66      	 405
10  	4.35      	 327
11  	3.37      	 242
12  	2.75      	 202
Year  	5.13      	4552
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  • System2
    System2 Posts: 6,290 admin
    #40
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    Re: 3.2 KW Residential install w/Enphase Micro-Inverters
    drees wrote: »
    Quick update - my permit was officially approved today. Planning on doing the install in about two weeks once I get all the miscellaneous parts (sub-panel, disconnect, wiring, conduit, junction box, etc).

    I'm looking at doing an installation in San Diego with Enphase inverters and have a question for you about your plan submittal to the City. Their guidance document indicates that "systems with micro inverters need to show disconnects in compliance with CEC 609.14(D)". Enphase's website says that the MC connectors meet this requirement. Did you have any problem with the city and what did you show on the drawing? Also, did you use the Wiley Electronics WEEB connectors for grounding? Any insight you have on this would be greatly appreciated!
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  • drees
    drees Solar Expert Posts: 482 ✭✭✭
    #41
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    Re: 3.2 KW Residential install w/Enphase Micro-Inverters
    lobodelmar wrote: »
    I'm looking at doing an installation in San Diego with Enphase inverters and have a question for you about your plan submittal to the City.
    FWIW - I live in Encinitas so they approved my plans, not San Diego.
    lobodelmar wrote: »
    Their guidance document indicates that "systems with micro inverters need to show disconnects in compliance with CEC 609.14(D)". Enphase's website says that the MC connectors meet this requirement. Did you have any problem with the city and what did you show on the drawing?
    I used a 2 pole 20A rated outdoor switch to avoid this issue. Though if I were to do it again, I'd submit the plans without the switch as wiring them up were a PITA and another moving part to fail over time. If they complained about the lack of a roof-top disconnect, I would submit the supplied documentation from Enphase with their argument against needing one.
    lobodelmar wrote: »
    Also, did you use the Wiley Electronics WEEB connectors for grounding?
    Yes, I used them for the modules but didn't for the inverters - I wish I had as the WEEBs make grounding simple. I did the install on a weekend so I couldn't source more WEEBs on short notice.

    Where are you getting your hardware?
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  • System2
    System2 Posts: 6,290 admin
    #42
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    Re: 3.2 KW Residential install w/Enphase Micro-Inverters

    Thanks for the quick reply. I haven't placed the order yet, but I think I'm buying the panel and inverters at Sun Electronics and the rack and other misc at Million Solar Roofs. I think that they have the WEEB grounding clips, but I'm not positive. I have a bunch of BP thin film panels that I installed a few years ago and am looking to add about another 1.5 kw with Canadian Solar panels and the Enphase inverters. Hoping to complete all of this by April or so.

    By the way, did you install a switch for EACH microinverter?

    I think that I'll follow your suggestion and try to get San Diego to buy off on the MC connectors as compliant.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #43
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    Re: 3.2 KW Residential install w/Enphase Micro-Inverters

    At most, you would need a lockable switch for each 15-20 amp 240 VAC inverter circuit (or a common lockable switch for all micro-inverter circuits).

    I would hope that you can get the building inspector/utility to buy off that no lockable switch is required.

    I believe I have seen some locking systems for circuit breaker lockouts... Perhaps, something like keeping those handy next to the panel/subpanel would make your inspectors happy.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • jcgee88
    jcgee88 Solar Expert Posts: 154 ✭✭
    #44
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    Re: 3.2 KW Residential install w/Enphase Micro-Inverters
    lobodelmar wrote: »
    I haven't placed the order yet, but I think I'm buying the panel and inverters at Sun Electronics and the rack and other misc at Million Solar Roofs.

    By the way, did you install a switch for EACH microinverter?

    If I were going to do a DIY, for the rack I would give strong
    consideration to this:

    http://www.solarflexrack.com/

    Their design allows more of the rack to be completed at the
    factory, thus less chance for a DIY-er to make a mistake.

    By the way, that being said, I would never do it myself, but
    that's because I hate working on electrical stuff! ;-)

    For Enphase installations, if you put in a disconnect, it is not
    at each micro-inverter.

    John
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  • drees
    drees Solar Expert Posts: 482 ✭✭✭
    #45
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    Re: 3.2 KW Residential install w/Enphase Micro-Inverters
    lobodelmar wrote: »
    By the way, did you install a switch for EACH microinverter?

    I think that I'll follow your suggestion and try to get San Diego to buy off on the MC connectors as compliant.
    No, one per string. I have 2 strings of 9, so I installed 2 switches. Definitely try to do the install without the roof mounted AC disconnect.

    Unfortunately, SDGE will still most likely make you install a utility accessible lockable AC disconnect - but you might want to try to talk them out of it since about half the utilities these days don't require one.
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  • System2
    System2 Posts: 6,290 admin
    #46
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    Re: 3.2 KW Residential install w/Enphase Micro-Inverters

    If I only have to install the lockable AC disconnect for SDGE, I'll be pretty happy. The switch is cheap and easy to install and I don't mind if it's a little ugly. I'm more concerned with avoiding the roof-mounted disconnect. Hopefully I'll get a sympathetic plan-checker/inspector from the city.
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  • drees
    drees Solar Expert Posts: 482 ✭✭✭
    #47
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    Mebin said:
    In design Plan you have stated that junction box is required to terminate one end of the Enphase inverters along with an AC disconnect switch for each string. Is AC disconnect switch per string in junction box required for all enphase project. Or it is just required in SDGE Utility.Please let me know if you have any information regarding this.

    A disconnect per string (aside from your typical circuit breaker) was not required at the time, but seemed like a good idea. I later learned that SDG&E had also removed the requirement for a solar disconnect as well.

    If I were to do the project again, I would not bother with any disconnects besides what's required by the utility.
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