Need Advice on Grid Tie Setup

wilsonbhwilsonbh Solar Expert Posts: 57 ✭✭✭
Want to install 10 400w panels but not sure if string (Xantrex 4.0) or using the micro-inverters, one on each panel is the best way to go. The area is completely free of shade and would get full sun most of the day. Any advice?

Comments

  • BB.BB. Super Moderators, Administrators Posts: 31,068 admin
    Wilson, I moved your post to its own thread... Should be easier for everyone to follow and keep on track to your questions/needs.

    First, what micro inverter are you looking at... 400 Watt panels are pretty large, can you find a micro inverter that can support that size of panel?

    Second, how hard is it to get on your roof/service the array if there is a failed GT micro inverter?

    Third, how much does their logging system cost? Is it worth it to you? Many micro GT inverter logging system require full Internet connection capability--Do you have Internet available at the location?

    Lastly, first micro inverters from "one company" have had "non trivial" failures in the field. While I hope that newer GT micro inverters have a lower failure rate--You should be prepared to possibly someday need to replace an inverter or two in the 20 year "life" of the system.

    Central inverters do fail too, but you do not have to get on the roof to replace them. (and solar panels can fail too--I am on my second array).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Dave AngeliniDave Angelini Solar Expert Posts: 5,501 ✭✭✭✭✭
    And micro inverters get the heat of a roof that the central are not exposed to, hopefully! Good questions Bill! I would add the joy of lifting a 400 watt panel.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • wilsonbhwilsonbh Solar Expert Posts: 57 ✭✭✭
    Great responses, thanks to everyone for the information. I'm bending towards the string inverter. I like the Xantrex. Getting on my roof is easy and I have a standing seam metal roof so attaching the panels can be done with clips that hold aluminum angle to which the panel can be attached. My roof space is limited so I'm after the highest wattage on each of 10 panels. I'm hoping to get 400w or higher. My roof is 34 feet wide by 10' so I'm hoping too that these 10 panels will fit in that space. I'm still learning and as my funds increase and knowledge along with it, I'll get this project underway in a few months. I live in Florida and have to work this through Florida Power and Light (FPL).

    Does anyone have a designed plan they would share? Something professionally drawn that shows their system setup would be very helpful to me. Could something like this be online here?
  • SolarPoweredSolarPowered Solar Expert Posts: 626 ✭✭✭
    For grid application micro inverter is the only way to maximize harvest and accelerate return on investment.

    According to the last 25years of PVwatts data at a de rate of 79.5% which has majority been recorded by string inverter systems and Poly panels. Micro inverter systems are harvesting between 8%~22% more power than the standard PVWatts estimates at string inverter derates, and is within 3% increase in harvest compared to Enphase Energy's PV watts derates estimates.

    The micro inverter system is ease of use and installation. Does not require calculations DC side conductors, meets all the requirements for NEC rapid shut down(so no additional disconnects are required).

    Total system component savings compared to string inverter systems is on average 6% and does not require combiner boxes, additional USE2 conductor, or disconnects.

    Micro inverter systems offer the ultimate in data monitoring, as you can monitor each individual panel, and the monitoring solution , for an example will save you 20% VS meter socket, and string inverter MPPT monitoring, and/or DC optimizer solutions for string inverters which is an added cost impact of 5% VS micro inverter monitoring solution.

    When a string inverter system goes down there is no more harvested production. That is 0% to the achievable return of energy.

    When 1 micro inverter goes down the rest of the system is still operational.

    1 in 250 micro inverters will malfunction within year 2.

    Micro inverters are backed for 25year warranty, while string inverters come with a 10 year warranty, and most manufacturers then sell an extended 25 year warranty.

    If you chose to go micro inverter the ABB models can accept only upto 350Wp, enphase M250 will only accept 310Wp.

    Comparables on the MPPT algorithm enphase micro inverters are slightly more tuned to maximizing the better harvest results at a lower amp input under 1amp rms. while the ABB requires 1.10 AMP RMS.

    Hope that helps.
  • PhotowhitPhotowhit Solar Expert Posts: 5,365 ✭✭✭✭✭
    For grid application micro inverter is the only way to maximize harvest and accelerate return on investment.
    I'll agree if the 2nd part is correct.
    According to the last 25years of PVwatts data at a de rate of 79.5% which has majority been recorded by string inverter systems and Poly panels. Micro inverter systems are harvesting between 8%~22% more power than the standard PVWatts estimates at string inverter derates, and is within 3% increase in harvest compared to Enphase Energy's PV watts derates estimates.
    Love to see a link to a non-bias site!


    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • SolarPoweredSolarPowered Solar Expert Posts: 626 ✭✭✭
    Photowhit wrote: »
    I'll agree if the 2nd part is correct.

    Love to see a link to a non-bias site!


    I can display the hard raw data from my systems. My company collects the R&D so the clients receive optimal performance for their ROI.

    The first 3 systems are using LG300N1C-B3
    Look at the life time harvest, not month to date, this region has been experiencing unusual cloud cover this month and last month. I use the Enphase calculator at 86.5% derate.

    This is a south bound system. Attachment not found.



    This is my west bound system with a 3% delta V facing south azimuth
    Attachment not found.


    This is my east and west bound system 18* tilt.
    Attachment not found.



    This system is using the SUNIVA 270 panels with M250 instead of the M215 because of discrepancies in the +3 power tolerance of the panels. This 4.860kWh suniva system out performs my old bosses sunpower 427B grade cell 5.124 kWh (sunny boy string inverter 5kWh) system on a daily average of 2kWh every day.
    Attachment not found.



    This system uses the Solar world 275 with M250 micro inverter. Attachment not found.
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