enphase s280 with LG315N1C-G4

[jrfiero]

When you run PVWatts again, pay special attention to the advanced parameter "DC to AC ratio". You system is sized at a ratio of 315 / 280 = 1.125. You can compare that to a ratio of 1.0 to see the amount lost to clipping. With your equipment, I would run the model at 8% loss and premium panels.

I didn't say that your clipping has or has not yet maxed out. Power output *will* decrease as temps rise, and the temperature at the panels is much higher than the ambient air, especially if they are mounted on a roof. From what I've seen, clipping for 3-4 hours in mid April will pretty much subside by June, but there is nothing wrong with waiting and seeing.

Sensij, good info, thanks. I should have said "(I note you say they won't continue to increase steadily)." Criticism aside, I love watching my system. I'll never see clouds quite the same way again!
Jonas

[J.P.M.]

One thing hard to quantify that may add to the perception and reality of clipping is the amount of overdesign (or looked at another way, the conservative guarantees or panel rating claims by mfgs.)

If, for example, a panel claims 315 Watts, +5/-0% at S.T.C., it's output might be and probably will be greater than 315 Watts at some time, not only because of some combination of higher irradiance, low incidence angle, low ambient temp. and a breeze, but also because it's efficiency is perhaps and probably a couple % or so higher than the spec sheet says.

Still, the amount of time an LG 315's output will be > 280 Watts and how much in excess of 280 Watts it will actually be will probably result in a small amount of the total annual output being lost due to clipping.

[randomuser]

Enphase has to be developing a larger inverter to come out "soon", right? Jrfiero is clipping with 315W panels. My LG 320W panels are sitting at my home, ready for install. What's LG going to have next year? I assume Enphase must have a new inverter in the hopper or they won't be perceived as an innovator.

[ButchDeal]

Enphase has to be developing a larger inverter to come out "soon", right? Jrfiero is clipping with 315W panels. My LG 320W panels are sitting at my home, ready for install. What's LG going to have next year? I assume Enphase must have a new inverter in the hopper or they won't be perceived as an innovator.

The S280 is the new inverter from enphase. They are late coming out with it and now it is pretty much too little too late

[jetsurgn]

Just a guess, but Enphase has to be working on a larger capacity.

[ButchDeal]

Just a guess, but Enphase has to be working on a larger capacity.

I am sure that they are but they just came out with the S280 and the module manufacturers are not waiting though.

[jetsurgn]

I clip with M250 / LG 310 but upgrading to the s280 won't be worth the upgrade cost.

[ButchDeal]

I clip with M250 / LG 310 but upgrading to the s280 won't be worth the upgrade cost.

that is my point. enphase is behind the curve on current production levels and is more costly than the competition.
Why pay for premium modules like LG310s and then not harvest all the power?

It would cost LESS on most systems to install SolarEdge than to install enphase (very small systems are the exception).
SolarEdge doesn't have the clipping and is easily able to keep up with new production levels.

[J.P.M.]

that is my point. enphase is behind the curve on current production levels and is more costly than the competition.
Why pay for premium modules like LG310s and then not harvest all the power?

It would cost LESS on most systems to install SolarEdge than to install enphase (very small systems are the exception).
SolarEdge doesn't have the clipping and is easily able to keep up with new production levels.

As has been suggested, running PVWatts and using the advanced parameters to adjust the DC to AC size ratio to = panel size/inverter size may give an approximation of clipping penalty by comparing the annual output to that using a "larger" inverter that doesn't clip and comparing the two #'s. Might be useful.

[Engineer]

I just had that exact system installed. 7kW total, 22 LG315N1C-G4 LG panels (315W) and S280 inverters. Enphase says "Commonly used module pairing – input power: 235 W – 365W", really it depends on the max input voltage with is 48V.

[ButchDeal]

S280 is a better fit than the M250 for these, should have negligible clipping with the S280.

[Engineer]

ButchDeal - yeah we've had a couple of perfect sunny days so far and no clipping I could see at all. Total system delivered 6.1kW peak on 6.9kW theoretical maximum.

[ButchDeal]

How does a 6.9kw system have a 3.9kw theoretical max???

[jetsurgn]

Engineer, what a wonderful system! I installed 12 lg 310 with the M250 so I'll be studying your system to see how much power I'm losing by not having the s280's instead.

[Engineer]

Thanks, I went for the best system I could instead of trying to save every dollar, being an engineer I can't stand anything less. Also I found that given that the base install cost was so much that paying for a bit more didn't add much to the system cost while it did bring down the cost/kWh.

[J.P.M.]

ButchDeal - yeah we've had a couple of perfect sunny days so far and no clipping I could see at all. Total system delivered 6.1kW peak on 3.9kW theoretical maximum.

How was that 3.9 kW estimated ?

[Engineer]

How was that 3.9 kW estimated ?

ACK, I mean 6.9 kW, I'll fix the post. Just 315*22=6930W

[jetsurgn]

I installed myself, and received the M250's at a great deal. The cost wasn't a huge concern, but I couldn't justify the 60 dollars extra for each inverter. I'm guessing I average 30 watts of clipping for 3 hours a day which totally stinks. But at the end of the day I'm enjoying the project and even thinking about my next addition. Power bill looks like it will be zero cost which is awesome.

[Engineer]

I installed myself, and received the M250's at a great deal. The cost wasn't a huge concern, but I couldn't justify the 60 dollars extra for each inverter. I'm guessing I average 30 watts of clipping for 3 hours a day which totally stinks. But at the end of the day I'm enjoying the project and even thinking about my next addition. Power bill looks like it will be zero cost which is awesome.

That's great, good for you. Wish I could have self installed, but I don't know enough about solar to have done that with my installation which was a little complicated. Even my installer which has been doing in the business for 30 years (long before it because a common thing) got down checks on the first inspection. Mainly around grounding, they needed to do the panels grounding slightly differently, separate the sub panel ground from the sub panel neutral, and run a separate #8 ground wire from the sub to the main (instead of the 10 gauge which was in the four wire 6 gauge Romex). All this for lightning protection it seemed.

[J.P.M.]

I installed myself, and received the M250's at a great deal. The cost wasn't a huge concern, but I couldn't justify the 60 dollars extra for each inverter. I'm guessing I average 30 watts of clipping for 3 hours a day which totally stinks. But at the end of the day I'm enjoying the project and even thinking about my next addition. Power bill looks like it will be zero cost which is awesome.

If that 30 Watts clipping X 3 hrs./day is all that's lost from the entire array production, I' d guess it will take some time for the NPV of the lost production from that clipping to equal $60/panel.