Have I got the wrong Inverter?

[Gavin A]

To be fair to SMA, they have pointed out to me in the past that their software shouldn't be relied on for yield calculations and that PV Sol should be used for that instead.

true, but the software ought really be able to be used to compare performance between one SMA inverter and another on any given system. That's really most of the point of the software. I agree though about not entirely relying on it, which is how we managed to pick up on it not factoring in the Sanyo's temperature performance advantages, and we'll over rule the softwares recommendations if there's a good reason for it.

Mostly it's pretty good at this, and it's really useful to see the variation in the inverter efficiencies for differents combinations of panels and inverters, which we then use to refine our more detailed performance estimates using PVGIS.

 

[lydart]

Just a quick update. After several phone calls I finally managed to speak to the Sales and Marketing Director who asked me to provide proof of the problems with my invertor. So I sent him some csv files and I finally heard back from him today, but only after I asked him for an update. He emailed me this reply.

“I have spoken toxxxxxx at SMA about this and they state that the 3000TL is an appropriateinverter for the panel combination you have (at the time of install). While thetop end will be “clipped” slightly on a sunny day the overall annualperformance figures provided by the 3000TL is greater than the 4000TL.

4000TL Units wereimpossible to source at the time of your install, 3600TL units were not inproduction so I contacted SMA to discuss at the time and they stated then asthey state now that the 3000TL is an appropriate inverter for your panelcombination.”

This is what’s happening.



Am I just worrying about a few kWh or will this become significant over the next few months?

 

[clivep]

We've just had our best result on Sunday 1st April with slightly over 20kWh produced.

3kW was reached at 11.00 and continued until 13.00. The SB3000TL may have slghtly clipped the output but it didn't seem as if the 4kW Hyundai panels were capable of putting out much more than 3kW. This seems to support their view of the inverter being the correct one.

The chances are that in summer any increase in air temperature will tend to limit the array's capability to generate at any higher power so the amount of clipping will still be small.

 

[loskie]

Our 3.6kwp system(18xKioto 200 panels and Aurora 3.6OUT) peaked today at 4040 watts. This too is the lifetime peak.
The weather was very dull and a gentle rain shower. The sun however was glaringly bright through the haze at 11;30am and I noticed the generation meter flashing rapidly. So went into loft and saw peak readout on inverter.
Generally today production was poor as I said it was/is constantly cloudy. Amazing the power of the sun through the cloud.
Our system was fitted mid October last year.
My calculations being right our Landis/Gyr meter should flash once every second when system is generating 3.6kw. Is that right?
We are in SW Scotland facing sse on about 40deg roof.

 

[flyman]

Loskie,


Not sure on your meter but on my Elster the pulse is for every watt produced so once a second is 3.6kwh.

Our 3.6kwp system(18xKioto 200 panels and Aurora 3.6OUT) peaked today at 4040 watts. This too is the lifetime peak.
The weather was very dull and a gentle rain shower. The sun however was glaringly bright through the haze at 11;30am and I noticed the generation meter flashing rapidly. So went into loft and saw peak readout on inverter.
Generally today production was poor as I said it was/is constantly cloudy. Amazing the power of the sun through the cloud.
Our system was fitted mid October last year.
My calculations being right our Landis/Gyr meter should flash once every second when system is generating 3.6kw. Is that right?
We are in SW Scotland facing sse on about 40deg roof.