SolarEdge and 135% limit.

[rsilvers]

My installer loaded up the SolarEdge to 135%, which SolarEdge says is fine.

I just found out it is capping my output to the 100% inverter AC rating though. On 17 days in the last many weeks it has hit this limitation. This means my power is being clipped. I hear it will get worse on cool spring and fall days.

I understand the power loss is probably not a huge difference, but I paid a premium to go from LG315 to 320 panels, and if I was willing to pay for that small difference, then that means I care the differences.

How hard should I press them to swap my inverter to a larger one to end this power clipping?

[ButchDeal]

SolarEdge has limits on the amount of DC power allowed on the inverters. Go over that and the warranty is voided. Some installers (seen some even mention it here) think that that is license and even recommendation from SolarEdge to install 135% over. It is not, it is a limit.

We try to avoid clipping. It seems quite trivial to do so, except in the most limited of electric situations.

Were there other reasons they might have wanted to limit your inverter? such as avoiding costly electrical upgrades...

[jflorey2]

I just found out it is capping my output to the 100% inverter AC rating though. On 17 days in the last many weeks it has hit this limitation. This means my power is being clipped. I hear it will get worse on cool spring and fall days.

Depends on your array angle. If it's ideal for summer (i.e. flatter than ideal) you may see a decline in power as you get further from June 21.

How hard should I press them to swap my inverter to a larger one to end this power clipping?

Probably not too hard. You are likely only losing a few watts per panel - and that's only for an hour or two a day. It wouldn't be hard to figure it out if you have the data.

[rsilvers]

This came up because the inverter shut down. The installer said it was too hot in the basement where the inverter is and that a extra fan would move some air around. I suggested the larger inverter so it is not run at the absolute limit.

The air temp under the inverter was 79 F.

I called SolarEdge and they said the air temp is ok.

[ButchDeal]

yep sounds like BS. they are well able to handle 79F air temps.

What inverter did you end up with?

[emartin00]

Why did you let them under size it so much? and the better question, why did they do it in the first place?
The difference between and 5k and 6k inverter is only like $50. Why would you skimp on $50 and end up losing out on power production.
If you have multiple strings that face different directions, I wouldn't hesitate to under size, because you will never actually hit that max power point. If they are all on the same roof plane, then this was poor design.

[rsilvers]

I didn't know there was any downside.

[DaveDE2]

rsilvers:
You might want to just disconnect one or two panels from the inverter that is shutting down and just keep them as spares. Little power loss and might be a lot less hassle than trying to get larger inverters. I'm assuming your two SE inverters are already11.4's the max single phase available from SE.

[silversaver]

I believe OP has 48 panels of 320W @ 15.36kW. I think he also has 2 inverters, just not sure what size of inverter he got.

[DaveDE2]

The OP apparently has two 11.4kW inverters and if they were undersized by a factor of 1.35 that means he has 30.8kW of array power.

[ButchDeal]

first year degradation will likely be close to 1%
you could get them to add an SE3800 for 26.6kw inverter capacity

[DaveDE2]

I personally wouldn't add anything unless you have cash spilling out of your pocket, maybe you do, but I'll bet the reason why that inverter shut down was because of just one extra panel in the string causing the overload.

If it were me, I'd joust the installer to come out and bypass one panel free of charge.

[sunnyguy]

Shouldn't the optimizers and inverter work together to avoid overloading, including bypassing panels if necessary?

[silversaver]

TIGO system has that option, not sure about SE.

[ButchDeal]

As long as it was installed correctly. I would check that they have three strings within spec on each inverter. I not installed correctly then who knows. What will happen

[bcroe]

Hmm, I wonder if only one inverter is ever clipping at a time? Depending on the sun and panel orientation. How about each string
contain a near equal mix of of panels facing different directions, can the optimizers handle that? Then each inverter would run at a
lower but longer peak over the day, and probably no clipping. Bruce Roe

[ButchDeal]

This was my suggestion before, to mix string orientations such that each inverter ran longer but maxed less.

[silversaver]

Hmm, I wonder if only one inverter is ever clipping at a time? Depending on the sun and panel orientation. How about each string
contain a near equal mix of of panels facing different directions, can the optimizers handle that? Then each inverter would run at a
lower but longer peak over the day, and probably no clipping. Bruce Roe

Good point! If his installer put all 48 X 320W panels facing 189 degree into one 11.4kW inverter, then he will run into problem. The installer might/can re-arrange the array input to solve the issue.

[bcroe]

Trying to see the options, but I couldn't find the pics that showed all the panels; guess they were deleted. Depending on the locations,
reconfiguring the strings to avoid clipping could make for some interesting MC4 extension cords. I just realized, multiple orientations
can allow a lot of extra panels WITHOUT increased inverter capacity, for both pure strings (mine), and for optimizers. Bruce Roe

[rsilvers]

I sorted my days of pvoutputs by total energy produced. And then within those, I picked the days with the highest peaks. And then within those, I deleted some that had sporadic cloud cover. These are the best examples that would show clipping.

As far as the strings - yes, they are poorly grouped to avoid peaks. All but six of the south-facing panels are on three strings of one inverter. And the other inverter has all of the west-facing panels plus the six remaining south-panels.

Seeing these curves, do you guys think I am losing sigificant energy to clipping of the inverter? I just want to know how hard I should push for them to upgrade inverters. Or if I should push for swapping strings in the existing inverters. Or do nothing.

Thank you very much.

[ButchDeal]

because you have multiple inverters, your clipping will now show up as a flat line. you might be able to tell more by looking at them individually on solaredge site.
or turning on the "Insolation" line in pvoutput and comparing to it (if you put in all the azimuths correctly).

[bcroe]

Certainly your south facing panels should be evenly split among the 2 inverters, and the same for the west facing; that is
the setup here. The cost is just wire; although perhaps more involved for you than on my ground mount. Be sure you
know the reason for shutdowns; should not happen. Bruce Roe