Announcement

Collapse
No announcement yet.

LG315 and IQ6 combination

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • LG315 and IQ6 combination

    My installer used iq6 instead of iq6plus with LG315 panel. Is it a right combination? IQ6 output power is 230 only. Will I loss electricity generated by LG315? Should I have chose 300 watt panels instead?

  • #2
    That combination has a higher DC to AC ratio than conventional design rules would allow. 315 / 230 = 1.37. The IQ6+, at 1.12, is a more common pairing. Whether that pairing (or a different PV panel) would be more cost effective depends somewhat on where you are and how the panels are oriented, the price of your electricity, and the cost of the alternatives.
    CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

    Comment


    • #3
      Originally posted by Neon View Post
      My installer used iq6 instead of iq6plus with LG315 panel. Is it a right combination? IQ6 output power is 230 only. Will I loss electricity generated by LG315? Should I have chose 300 watt panels instead?
      Solar Panels do not generate Max Power all day long.
      They start low in the morning, peak at Solar Noon, and then fall off in the evening.
      The 315 Watt PV Panels will generate slightly more Watt-Hours (energy) almost all day long vs 300 Watts Panels,
      except for the +/-1 hour near Solar Noon on a very sunny day.

      So, why would you install 300 Watt Panels and generate less energy?

      Comment


      • #4
        Seems to me that a micro with a lower power rating is like choosing a higher power ICE to get as much power as needed, and then putting a governor on it that limits the output at times.

        Comment


        • #5
          Originally posted by J.P.M. View Post
          Seems to me that a micro with a lower power rating is like choosing a higher power ICE to get as much power as needed, and then putting a governor on it that limits the output at times.
          I think that is called restrictor plate racing in NASCAR

          Comment


          • #6
            Good question Neon - hope this gives you some useful information.

            The IQ6 has a continuous output of 0.96amps ac thus 230W. However it will peek at 240W - basically 1amp output, and it will thermal throttle down as needed to stay in its internal temperature range. The IQ6+ is 1.17A output - 280W and it can peak to 290W - about 1.2 amps.

            As described above the majority of the time you will not be peaking that 240W, (clouds, morning, afternoon) but some clear days at noon assuming everything is aligned right you are clipping and losing some output. However my best guess is your installer when planning the system was able to use the fact that the IQ6 is basically a 1 amp output and thus it makes the math real easy when combining inverters to organize them into strings protected by a 20amp OCPD and reduce the cost of the installation.

            Let me give you an example. Lets say you have exactly room for 32 panels on your roof. This means your installer would most likely setup them up into two strings each protected by a 20 amp breaker using the IQ6. 16 x 0.96 x 1.25 = 19.2, round up to 20 for each string.
            If you use the IQ6+ then you would need three strings, two strings of 13 x 1.17 * 1.25 = 19 round up to 20, and a third string of 6 x 1.17 * 1.25 = 8.78 round up to 10. Thus to use the IQ6+ the installer needs 50 amps of OCPD and room for three breakers to meet NEC calculations, but for the IQ6 only 40 amps of OCPD and two breakers. If you don't have room for three breakers but do have room for 2 then the installer would need to install a MLO style subpanel - more cost. Also it makes a difference if you have a 200 amp service panel which can take that 40 amps without having to down rate the main 200 breaker but with the IQ6+ he will have to replace that 200 amp breaker with a smaller one - and these are expensive. The power output difference over a year is not that much but the cost saving may be worth it.

            If you really want to know the output differences, PVWatts would be a good place to start.

            We don't know your setup but these are the sort of things one does when designing to decide the best benefit / cost.

            Comment


            • #7
              I have the LG 315 panels and the older S280 enphase inverters. The S280 have similar power capacity as the IQ6+. I can state emphatically that I get clipping in the middle two hours of the day during the peak part of the year (generally april/may timeframe). I've got a flat roof with optimally tilted panels and I live in Tucson, which gets a lot of sun, so that's a factor.

              I ran the numbers once to see how much money I'm losing because of the clipping and it was very minimal. Couple dollars per year. That said, I only get clipping for a few months and for a short time in the middle of the day. If I were to put on IQ6 inverters I'd be clipping nearly every single day and for many hours during the peak part of the year. You could run the numbers on your own system, but my initial reaction would be that the cost delta between the 6 and the 6+ is small enough that it would be worthwhile if it were on my roof...

              EDIT: Just an FYI, I just looked at my production for the last week in December (when the sun is the lowest, and thus least bright of the year) and with the LG315 panels I get consistently around 260W per panel in the middle of the day.
              Last edited by rszimm; 01-10-2018, 11:50 AM.

              Comment

              Working...
              X