Micro Inverter position on rack

SLOWEB
SLOWEB Registered Users Posts: 3
in PV Installers Forum - NEC, Wiring, Installation #1
After reading thru the install specs for both the Enphase M215 (IG) and various panels, and considering possible micro inverter replacement, I am surprised that I have not seen any install photos that show the M215 installed to the outside of the rack frame, still under the panel.

Consider this scenario:
  • A 2 row array of portrait panels, installed 3" off of metal high rib roof to help with ventilation
  • Panels installed on rails, 10" from end (meeting panel specs)
  • M215-IG and Engage cable installed to outside of rails, under the 10" setback

This would still seem to meet the "under the panel, out of the sun" M215 requirement, and yet make M215 replacement a snap.. Not having the inverter grounding cable to deal with and all connections under the panel reachable from the outside, the panel would not have to be removed. Granted, this would require a small angle mounting adapter for the M215.

This seems like it meets all requirements, and would make potential replacement very easy. But I never see this setup, what am I missing?
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Comments

  • jaggedben
    jaggedben Solar Expert Posts: 230 ✭✭
    #2
    Re: Micro Inverter position on rack

    There's nothing wrong with the idea. What you're describing is how experienced installers do it when they can. For example on a single row installation we'd put the inverters above the rail so that the serial numbers and LED indicators can be more easily seen looking down from the top.

    However, there's an issue with doing it on a two row (or multi-row) installation. That's because the portrait Engage cable won't reach from the top rail of the top row to the bottom row of the bottom rail. You'd have to waste a drop connector (cheapest option), i.e. buy a cap and not use it. That's probably why you'll typically see the inverters and cabling installed on the center rails of two-row installations.

    Is it worth spending an extra $20 to potentially not have to remove panels later? That's up to you. So far the M215 has been a lot more reliable than the M190.

    It's true, with the new IG version, that a bit of deft execution with a 7/16" open box wrench could save your having to remove a panel to replace an inverter. :-) Then again, you never really know what you'll need to address on your array.
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  • SLOWEB
    SLOWEB Registered Users Posts: 3
    #3
    Re: Micro Inverter position on rack

    Ben, thanks for confirming what seemed obvious to me.
    Having to "waste" a drop connector is not an issue, as it is a 2x17 array, and 2 strings are needed.
    As far as deftness with a 7/16" wrench, I am considering using a short piece of aluminum angle to bolt to the M215 flange and then bolt to the vertical face t-slot of the IronRidge XRL rail. that would allow easier access.

    All of this is prompted by the possibility of having to support the system myself in the future, even if I pay to have it installed. Being able to easily diagnose by swapping inverters, etc would be a time bonus as well as getting more serious consideration from Enphase, if a replacement is needed. By that, I mean that if I say that I swapped the inverter out to 2 different panels and I still get the same low performance - that is bound to be more convincing than "It is not producing as much as the others".
    So while a service company may not mind spending (and charging for) extra time pulling panels, it seems like a little thought up front could pay off in the future.
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  • SolarPowered
    SolarPowered Solar Expert Posts: 626 ✭✭✭
    #4
    Re: Micro Inverter position on rack
    SLOWEB wrote: »
    After reading thru the install specs for both the Enphase M215 (IG) and various panels, and considering possible micro inverter replacement, I am surprised that I have not seen any install photos that show the M215 installed to the outside of the rack frame, still under the panel.

    If you want to spend up to $50 more in parts (trunk cable, and connectors, or rain boxes flex conductor). If you want to spend the extra labor I guess you can figure it out the hard way.
    The smart guys that have been designing know a trunk cable is only so long between inverter connections. The theory is if you don't need to cut or add to the cable you are maximizing your install efficiency.

    Also to replace an inverter, you still have to unbolt a panel, to get to the inverter, if you are following the directions of enphase install, or most micro inverter installs. Nothing about replacing parts is a snap.

    Besides if you are charging the correct rate for inverter replacement from your customer, not the manufacturer, you should be making ($215, or $250) for a 1 hour inverter replacement, minus your drive time, you should be charging a $1 per every watt that inverter produces. Really for the 215 it should be $226, 215 is the CEC rating
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  • SLOWEB
    SLOWEB Registered Users Posts: 3
    #5
    Re: Micro Inverter position on rack

    Actual cost to mount M215/250 in manner that meets manufacturer's specs and still be able to replace without touching the panel is less than $2 - plus a little forethought during the installation.


    This is an owner self install, thus the interest in saving any future labor.
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  • SolarPowered
    SolarPowered Solar Expert Posts: 626 ✭✭✭
    #6
    Re: Micro Inverter position on rack

    On one final note, solar theft does happen.
    If you think you do have a design feature that makes it easier for you do it, I don't care.
    Every aspect of design has to be considered, I actually marine epoxy 2 of 4 of my unirack clips to nut as a theft detourant. For me if 5 or 10 extra minutes of my day is consumed from doing a job right the first time, keeping the equipment protect and safe is more important to me, I don't even think twice about the easy approach for maintenance coming back to fix the equipment, I get paid either way, and you should trust your inverters to last a minimum of 10 years, so take time and depreciation, VS. time and money whihc at that time should mean nothing to all the kWh the system made through out a part of its life course.

    Your whole argument or how you want to install is moot. Its your house do what you want, but when the professionals tell you it sounds funny, or doesn't seem right its probably better to just follow the norm of every one else. But hey your the owner, its your house, and you seemed pretty determined to do it any way so do it.
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