New owner, trying to figure out this clipping deal

[J.P.M.]

I believe the older SE10000A Inverters were 97.5% CEC Weighted Efficiency. The SE10000H inverters are 99% efficient.

You are probably correct. If so, adjust my numbers accordingly. The method I described is rough and approx. enough and is such a bastardization of the model's original and stated intent that it won't make much difference when used as an approx. eval. tool. I used the slightly more conservative CEC rated efficiency. Maybe my spec sheet is on old one.

[Ampster]

............I would also see if you can get the 25 year warranty on the inverter, because if clipping is common that inverter will have a much shorter life.

My installer used the Solaredge design tool to give me a system with a 1.5 to 1 AC to DC ratio (150% overclock). I asked him to run the design tool using a 5.0 kW inverter. That analysis showed I was losing 400kWhrs per year.

What I wished I had done is to ask him to run the simulation with one more panel. That would have required the next sized inverter and brought the AC to DC ratio closer to 1 to 1. It also would have given me some expansion room. It was a sales opportunity that they missed because I would have gone with another panel for an additional several hundred dollars.

The contract included a 25 year warranty so I am not as worried about the stress on the inverter.

[discodanman45]

My installer used the Solaredge design tool to give me a system with a 1.5 to 1 AC to DC ratio (150% overclock). I asked him to run the design tool using a 5.8kW inverter. That analysis showed I was losing 400kWhrs per year.

What I wished I had done is to ask him to run the simulation with one more panel. That would have required the next sized inverter and brought the AC to DC ration closer to 1 to 1. It also would have given me some expansion room. It was a sales opportunity that they missed because I would have gone with another panel for an additional few hundred dollars.

The contract included a 25 year warranty so I am not as worried about the stress on the inverter.

That is a bad system design... 400 kWh is not minimal and it could be more than that. For a system like yours, you could have jumped for a higher inverter at minimal cost.

For the warranty, I don't know if installation is covered... If your inverter fails because of being pushed so hard, will the installer charge you for the electrical work? Having someone replace an inverter is pretty easy, but labor is expensive. I also noticed de-rating happen a few times when my inverter got to 190 degrees. I got huge spikes downward a few times on perfectly sunny days. The inverter was trying to protect itself from the high temperatures. I also wonder if SolarEdge would honor warranties from severe overclocking without having a good reason for it like E/W arrays or shading. If SolarEdge says to the installer tough luck, you didn't follow our recommendations for overclocking, would your installer purchase a new inverter for you?

Just a few things to think about.

[Ampster]

I believe the older SE10000A Inverters were 97.5% CEC Weighted Efficiency. The SE10000H inverters are 99% efficient.

Yes, mine is a HD Wave (H series) and apparently it has a flatter efficiency curve. One of the arguments my installer used for a high DC to AC ratio was that I would get more production in the morning and afternoons because the inverter was more efficient if run closer to 100%. Apparently that was BS because of the higher efficiency and flatter efficiency curve of the HD Wave series of inverters.

[Ampster]

That is a bad system design... 400 kWh is not minimal and it could be more than that. For a system like yours, you could have jumped for a higher inverter at minimal cost.

For the warranty, I don't know if installation is covered... If your inverter fails because of being pushed so hard, will the installer charge you for the electrical work? Having someone replace an inverter is pretty easy, but labor is expensive. I also noticed de-rating happen a few times when my inverter got to 190 degrees. I got huge spikes downward a few times on perfectly sunny days. The inverter was trying to protect itself from the high temperatures. I also wonder if SolarEdge would honor warranties from severe overclocking without having a good reason for it like E/W arrays or shading. If SolarEdge says to the installer tough luck, you didn't follow our recommendations for overclocking, would your installer purchase a new inverter for you?
...........

Believe me, My dialogue with the installer was a long one. In the end his boss gave me a $1000 credit. It was a missed sales opportunity for them because I would have spent $750 for more wattage. The credit was not for just the clipping but for the delays getting the Permission To Operate which took over 14 months from the time of installation, That delay was caused more by the difficulty of upgrading my main service panel which was part of the contract. The installer used the Solaredge design tool and the max DC to AC ratio allowed by Solaredge is 1.55 to 1. My system is 1.53 to 1.
I am not worried about the risk of installation expense. I can do the work myself because I have installed inverters before. We do have some hot sunny days here and I will review past production or keep an eye out for derating next summer. I purposely had them install it inside my garage rather than on a south facing exterior wall so it would run cooler. In addition I have a heat pump water heater that keeps that space cool in summer.

[ButchDeal]

My installer used the Solaredge design tool to give me a system with a 1.5 to 1 AC to DC ratio (150% overclock). I asked him to run the design tool using a 5.8kW inverter. That analysis showed I was losing 400kWhrs per year.

What I wished I had done is to ask him to run the simulation with one more panel. That would have required the next sized inverter and brought the AC to DC ratio closer to 1 to 1. It also would have given me some expansion room. It was a sales opportunity that they missed because I would have gone with another panel for an additional several hundred dollars.

The contract included a 25 year warranty so I am not as worried about the stress on the inverter.

The SolarEdge design tool is great to stringing and making sure you have a system that is within Warranty but it does not automatically choose the best inverter for the sitation.
We used AuroraSolar which does all the stringing as well as a full model simulation with a 3D world for shadows, etc and reports on the clipping.

[ButchDeal]

One of the arguments my installer used for a high DC to AC ratio was that I would get more production in the morning and afternoons because the inverter was more efficient if rund closer to 100%. Apparently that was BS because of the higher efficiency and flatter efficiency curve of the HD Wave series of inverters.

That is major BS and an installer that has no idea how SolarEdge works. It is an argument that Enphase pushed a few years ago and many installers that sold enphase think it was gospel; it was always BS.

[Ampster]

That is major BS and an installer that has no idea how SolarEdge works...

Yes it was and that employee is no longer working there. I had had a previous experience with that company on a 100 kW install in a City in which I was involved. They performed well in that instance and I had a communication channel to the CEO if I needed it. It was all resolved to my satisfaction.

[bcroe]

One of the arguments my installer used for a high DC to AC ratio was that I would get more production
in the morning and afternoons because the inverter was more efficient if run closer to 100%. Apparently that was BS
because of the higher efficiency and flatter efficiency curve of the HD Wave series of inverters.

Inverters are already so close to 100% efficient, the VARIATION in efficiency is barely worth consideration. Some percentage
increase over 1:1 of DC to AC is justified to cover DC and inverter losses, and a (roof) mount angle not close to optimum.
For a higher ratio on a simple S facing array, gain of a bit more early/late energy is at extreme loss to midday clipping.

Larger increases might be justified with E and W facing (roof) mounts, where the 2 groups of panels peak at spaced out
times of day. Here a higher ratio is used to boost somewhat cloudy output, having done that, the question is how to avoid
severe clipping loss under ideal sun. The answer for this ground mount, is once again align panels to largely E and W for
a broad but not mid day peaked output. An inverter is fed by panels from both groups, not in the same string. Bruce Roe

[JSchnee21]

If it were me, while you're system is brand new, I'd work out a deal to swap out the 10kw for the 11.4kw. Cost effective or not, it will bother you until you either 1) do it 2) move 3) meet Ra (the sun god). Well, it would both me, at least (-:

[Yet another Yeti]

Interesting read .

In the main German online forum for photovoltaik , there is the usual opinion , that inverters should be
chosen 1 size smaller , than the kWpeak size of the installed solar generator .

The opinion is that , that the little 2-10% more of harvest does not pay the higher price of 1:1 sized inverters .

Smaller inverters usually have a lower Umppmin to start the Maximum Power Point Tracking voltage range ,
which had been the argument by the installer , to better harvest earlier and later a day .
And when the outside temperatures are high, the solar panel usually produce at 2/3rd of their Nameplate capabillity .


Some inverter brands also have active Shadow Management software running inside the inverter's microcontrollers,
adding some adjustments to the MPPTracking , though that might lead to higher self consumption of the inverters .


Feed-in-Tariffs and cheap loans by the government demand a VAac feedin cut at several levels :
Some 70% fixed , some 50% fixed ,
and some floating at 100/60/30/0 % by remote control of the local grid operator .


But there might be reasons to use oversized inverters :
capable of higher currents, more MPP-Trackers, future outlook for expansions .

The solar panels increase their voltage and current each 5-Watt-step , and a lot of inverters as of today
will not be able to handle 400+Watt panels comming up in future .

[ButchDeal]

Interesting read .

In the main German online forum for photovoltaik , there is the usual opinion , that inverters should be
chosen 1 size smaller , than the kWpeak size of the installed solar generator .

The opinion is that , that the little 2-10% more of harvest does not pay the higher price of 1:1 sized inverters .

Smaller inverters usually have a lower Umppmin to start the Maximum Power Point Tracking voltage range ,
which had been the argument by the installer , to better harvest earlier and later a day .
And when the outside temperatures are high, the solar panel usually produce at 2/3rd of their Nameplate capabillity .

This is not the case with SolarEdge. The optimizers that the OP has will boost the voltage to get the inverter operating far earlier than other inverters regardless of the inverter size.

Some inverter brands also have active Shadow Management software running inside the inverter's microcontrollers,
adding some adjustments to the MPPTracking , though that might lead to higher self consumption of the inverters .

those inverters would be optimized

But there might be reasons to use oversized inverters :
capable of higher currents, more MPP-Trackers, future outlook for expansions .

OP has SolarEdge which has optimizers. Optimizers have MPPT on every PV modules

The solar panels increase their voltage and current each 5-Watt-step , and a lot of inverters as of today
will not be able to handle 400+Watt panels comming up in future .

Not sure why you think this but SolarEdge has a P505 optimizers capable of handling 500 watt PV modules

[Yet another Yeti]

MODERATOR: He/She has been warned previously about running amok at the keyboard without any clue as to the accuracy of the output.

All postings by Yeti are suspect as to safety and accuracy.


In Germany , these Optimizers are not widely used , as it is probably elsewhere , like the USA .

Most people fear the additional work , if some of these optimizers fail and need replacement .

Are there any experiences , how Solar Edge performs against traditional string inverters ?

One thread I had read here on the forum , some member complained about failing components like
optimizers , and advised to apply traditional string inverters .

I personally have no experience with the system of Solar Edge or Tigo .

[bcroe]

In the main German online forum for photovoltaik, there is the usual opinion, that inverters should be
chosen 1 size smaller, than the kWpeak size of the installed solar generator. The opinion is that ,
that the little 2-10% more of harvest does not pay the higher price of 1:1 sized inverters.

Everyone is entitled to an opinion. I would never give up 10% production over incremental inverter
cost, the $ is not the only factor. There are other reasons such as AC output restrictions.

Smaller inverters usually have a lower Umppmin to start the Maximum
Power Point Tracking voltage range , which had been the argument by the installer , to better harvest
earlier and later a day.

Obviously this has never been actually measured out. In the first place, my larger inverter is able to
actually use a larger and a smaller inverter internally, so it will go even LOWER than a lesser inverter.
The 7500W (German) inverter will run down to 27W, or 0.036% of max. The power difference in
bringing this down by the fractional difference in inverter size, multiplied by the extremely short time
it takes the sun to move down that much, is like an extra grain of sand in a bucket full. Bruce Roe

[Yet another Yeti]

What about the performances during weeks of 100% clouded skies , like we have in the North during December ?

Is there really a measureable intake and output , that is worth to keep the solar generator in operation , or would
it not really matter to shut it down during the winter solstice weeks ?

People in Germany start to put solar panels on the north side , if the angle of the roof is low as less than 20