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APSystems YC500 500W Microinverters solar panel pairing

Discussion in 'Energy, Environment, and Policy' started by Skotty, Jun 11, 2017.

  1. Skotty

    Skotty 2014 Model S P85

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    To someone with more electrical engineering knowledge than me, am I correct that the APSystems YC500 line of microinverters, with maximum output power of 500W, will not be able to take full advantage of newer 300+W panels (important note! the YC500 serves 2 panels, not just 1)? Can I just use straight addition here, meaning really any panels over 250W the YC500 will start losing energy on at peak generation? In the datasheet, it says it can accommodate PV modules up to 365W, but is ideally suited for modules from 280 to 310W. Does that make sense when the max power output is listed as 500W?

    This is kind of important to me, because one of the solar installers I am looking at had a plan that included these APSystems YC500 microinverters paired with 265W panels. But that was awhile back. Panels I would consider now will likely be rated much higher, probably 300W or higher. If they are still using the APSystems YC500 microinverters, will I be losing energy with 300+W panels?

    Here's the datasheet: http://usa.apsystems.com/wp-content/uploads/2017/03/APsystems-Product-Datasheet-YC500A-3.30.17.pdf

    Thanks for any thoughts.
     
  2. nwdiver

    nwdiver Active Member

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    You will be losing some energy but it's probably negligible. The power rating on a panel is under rather ideal conditions... ~20C and 1000w/m^2. These conditions are not typical. With panels as cheap as they are I regularly oversize my systems by ~1.4. So I wouldn't hesitate to put 700w of panels on that 500w micro.

    This is 10.8kW on a 8kW inverter. Really not losing a lot even on a really good day... IMO it's not worth the larger inverter and more wire.

    IMG_1254.PNG
     
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  3. Skotty

    Skotty 2014 Model S P85

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    Thank you. I figured you would provide some input here, and it's appreciated. Your assessment seems to fall reasonably in line with APSystems datasheet claim of the inverter being ideally suited for 280 to 310W panels. If they are still using those microinverters, sounds like we should aim for roughly in that range for the panels.

    Another thought, panels supposedly lose a little efficiency over time. So even if oversized a bit, within a number of years it should even out to where you are getting full benefit.
     
  4. SmartElectric

    SmartElectric Active Member

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    I'm interested in the price advantages of APSystems YC500 vs the Enphase M215 or M250 products.

    Here in Ontario Canada, I can get Enphase for around the same price as the APSystems all-in, so any delta between them would need to be at the product/technical level.
     
  5. andrewket

    andrewket Well-Known Member

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    I've got LG 320w panels on enphase S280 inverters and my system clips for just shy of 3 hours on good solar days (no clouds, etc) during the summer. The higher capacity panels are more efficient, so there is still value to oversizing. However, if I was doing this again, I'd look hard at solar edge with a central inverter that can be appropriately sized so that clipping never occurs. I think solar edge's design is superior to enphase.
     
  6. nwdiver

    nwdiver Active Member

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    I'm not a huge fan of micros... they're just too expensive...

    With string inverters that now have 2 or 3 MPP trackers the advantage of micros is further reduced. The last install I did each string was on it's own tracker. Every panel has 3 bypass diodes to shunt current from shaded areas... I don't see how there can be a significant output difference between a tracker per panel or pair of panels vs a tracker per string. The new SMA inverters are <$0.20/w vs >$0.40/w for micros... that's not a small difference...
     
  7. SmartElectric

    SmartElectric Active Member

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    Fair enough, let me describe the situation:

    2kW of solar, around 10 panels
    likely one area, but may split deployment across two different areas of property 100 feet apart
    likely to re-use 240 watt panels from a barn install that was pulled down before barn was dropped @ $100 Canadian(!) / panel
    locations are on 30 degree south facing slope of a ravine lot with various daily shading from trees
    ground mount will be trivial "flat structure" which can be then fixed to elephant feet (location is sheltered from wind)
    already have 240V lines near most primary locations

    Therefore, something simple like micro inverters makes sense.


    Cons of using larger DC inverter for my specific plan:

    Running DC wire around property when I already have AC in most of the possible panel locations would be a pain.
    Building a structure to hold inverter near panels so I can reuse existing AC runs would be a pain
    The inverter family you listed are typically in the 3 kW range which is way overkill for the size of array planned.
     

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