Compatible panel for Enphase micro inverter?

spurlocktools
spurlocktools Registered Users Posts: 11 ✭✭
in Solar Beginners Corner #1
A 230 watt panel is recommended for the Enphase M190 Micro Inverter. Just wondering if anyone knows whether a Kyocera KC158 will work with it. I happen to have an extra one of these panels and would be willing to buy a used $99 Enphase on Ebay if it might work with this panel. Voltage and current specs on the panel seem to be within the window specified by Enphase, just much lower wattage than recommended.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,641 admin
    #2
    Re: Compatible panel for Enphase micro inverter?

    Assuming the smaller Kyocera falls within the Enphase input voltage/power/current requirements, it should work fine (and just produce less energy).

    You may also find that it requires a bit more sun to "turn on" first thing in the morning.

    HOWEVER, as I understand, the panel must be on the Enphase module compatibility list (PDF) for their installation to comply with the NRTL rating and with the NEC for installation and connection to the home/business utility wiring. (again, I am not an expert here--just what I remember reading a while ago--The Enphase site does not specifically state the NRTL/NEC impact of non-listed solar panels).
    The modules on this list have been verified for electrical compatibility with Enphase Microinverters over the temperature range of -25C to +75C. For applications outside of this temperature range, the system designer should verify that the module voltage and/or current does not exceed the microinverter model's nameplate ratings under all expected environmental conditions. The module specification sheet contains all of the necessary module information to make this determination. The ASHRAE Handbook is the recommended source for weather data for a particular location.

    IMPORTANT NOTE: The following listing does not address module performance. The correct module size for your application will depend on the specifics of the installation, as outlined in the "Module Rightsizing" whitepaper available on the downloads page, and should be determined by the system designer. A commonly accepted practice is to use a module with an STC power rating of 1.2 times the AC power output rating of the inverter. Many system designers use a multiplier of 1.25 or 1.3. For an M190 this would suggest a module power rating of 228 to 250 watts.
    From their FAQ:
    With which solar modules is the Enphase Microinverter compatible?Please view the Module Compatibility List for a list of all modules that work with the Enphase Microinverter. The Model M175 240V and Model M175 208V work with 72-cell modules (24V nominal) up to 210-215Wstc. The Model M190 208V and Model M190 240V work with 60- and 72-cell modules up to 230Wstc. The Model M200 208V and Model M200 240V work with 96-cell modules (32V nominal) up to 240Wstc. The model M210 208V and Model M210 240V work with higher voltage 72 cell modules (28V nominal) up to 240Wstc.

    Why are SunPower modules not included in the Enphase Compatibility List?Even though some SunPower modules are electrically compatible with Enphase Microinverters, SunPower has not approved Enphase Microinverters for use with their modules and consequently we are not able to put their PV modules on our compatibility list.
    Although, from one of their manuals, I may be wrong about the requirement that panels be "listed" by Enphase:
    The Enphase M190 Micro-inverters are designed to operate with most 60 and 72-cell PV module configurations. Be sure to verify the voltage and current specifications of your PV module match with those of the Micro-inverter...

    WARNING: You must match the DC operating voltage range of the PV module with the allowable input voltage range of the Enphase Micro-inverter.

    WARNING: The maximum open circuit voltage of the PV module must not exceed the specified maximum input voltage of the Enphase Micro-inverter.
    Perhaps, you are able to "legally" do your own due diligence.

    By the way, there have been a few questions about Enphase (and other GT inverters) and the wisdom of installing solar panels that are rated over the inverter's maximum power rating--Here is a white paper from Enphase that I ran across while trying to address the above question:

    Module Rightsizing - PV Module “Right-Sizing” for Microinverters

    -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 ✭✭
    #3
    Re: Compatible panel for Enphase micro inverter?
    BB. wrote: »
    By the way, there have been a few questions about Enphase (and other GT inverters) and the wisdom of installing solar panels that are rated over the inverter's maximum power rating--Here is a white paper from Enphase that I ran across while trying to address the above question:

    Module Rightsizing - PV Module “Right-Sizing” for Microinverters

    -Bill

    My contractor provided me with that paper some time ago,
    when I asked him how he matched up an M190 (190w rating)
    to a Sharp 235w panel.

    The paper's conclusion is that basically that an M190 will
    match up with panels up to the ~240w range. This is
    based on the criteria of maximizing harvest.

    That being said, I felt this whitepaper was poorly written,
    and its data tables supporting this conclusion were not
    easy to figure out. If I were grading this paper, I'd give it
    a "C".

    John
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,641 admin
    #4
    Re: Compatible panel for Enphase micro inverter?

    I don't know about the "C" grade from seeing how my kid's papers are graded in a 2 year college... "A"? :roll::confused:;)

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • drees
    drees Solar Expert Posts: 482 ✭✭✭
    #5
    Re: Compatible panel for Enphase micro inverter?

    The voltage specs on the panel are just barely within the range that Enphase is looking for from what I can tell:

    Enphase M190 specs:
    MPPT voltage: 22-40
    Min/Max start voltage: 28-54

    Kyocera KC158G specs:
    Voc: 28.9
    Vmp: 23.2

    In hot weather I would expect the voltages to drop enough that MPPT might be an issue and the start voltage may be marginal, too.

    For example, my ET-M572180 has a Voc of 44.6V and a Vmp of 36.3V.

    The Enphase unit wakes up once it sees 28V, voltage slowly climbs up to Vmp (36V) until mid morning then as it warms up (around 70*F max ambient) the voltage drops down to 32.5V.

    So I would expect your panel to take some extra time to wake up and then lose some MPPT efficiency when the panel warms up. But - it will probably work. Take a volt meter and measure the voltage of your panel under the sun to confirm that it hits 28V. If you watch the voltage it will drop as the panel warms up even with no load.

    Anyway, $99 for a used inverter is cheap - and if it doesn't work you can probably just sell it on eBay again for no loss.
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