Replacement SolarEdge inverter producing 10% less power?

[Undebt]

I have 6kw of panels connected to a SolarEdge HD wave 6000 inverter. The original inverter was installed 3 years ago and was the older style with the blue screen. That one died a couple of weeks ago and SE replaced it with the newer setapp enabled HD6000. It was reinstalled by the original solar installer.

My question is, is it possible that the new inverter is producing 10% less power than the old one? I have a TED energy monitoring system and the new inverter is peaking during the day at only 4700wh when under the same conditions it use to peak at 5200wh. Also, on a cloudless day my daily production has dropped from around 43kwh to 38kwh. The last week with the old inverter was averaging 42kwh per day on cloudless days, then the next week the system was down, and the week after that with the new inverter I'm averaging 37kwh on similar days.

Any ideas appreciated.

[J.P.M.]

One idea: I'd start by getting ahold of the installer and show him what you just posted here with a copy to SolarEdge.

[scrambler]

Do make sure your panels are clean to eliminate variables.
Looking at the production curve, do you see the same curve just lower all the way, or do you see clipping at the top of the curve.

If it is clipping at the top (flattening of the curve during peak hours) that is lower, the inverter derating could be set lower.

Also, you have individual panel optimization, so you should have individual panels monitoring, if so, have a look at the individual panels variation and the string variation during the day.

I noticed that a sign my Inverter is throttling the solar production is that it does it by modulating the strings independently, so assuming you have no shade issue, if you see a whole string getting lower, it is likely the inverter doing something.

That will also show you if something happened to some panels, which could also be responsible for some capacity loss

[PugPower]

On paper the newer SolarEdge HD Wave inverters are slightly more efficient than the previous models. So under identical conditions you should the same output as you did before if not more. If the environmental temperature increased from one week to another, that would explain the decrease in production. Solar PV systems are less efficient in higher temps.

[theoak]

Setup the same? Country (code) set to what you had prior? Did the installer do any custom settings on your old inverter?

With that being said, this past week I have seen similar drops. In my area I have had about a 10 degree F increase in temperature putting me at around 100 degrees F. The heat is impacting my production.

Edit:

What about pairing? Are you using Power Optimizers? Are all of the Power Optimizers paired? Do you have access to the monitoring portal? Are all of your panels producing?

[Undebt]

Thanks for all of the input. Some additional information - Things have gotten cloudy in the last couple of days so comparisons are difficult, but prior to that we had virtually the same conditions for 3 weeks. Full sun, no clouds for the entire day(s), but the temps are about 10F higher which probably accounts for most of the discrepancy. Week 1 was the old inverter, week 2 was no inverter, and week 3 was the new inverter. System uses optimizers, all are paired and all panels are producing. All panels face due south with no shading all day. At the panel level most of the panels produce very similar power, with a couple them +5% and a couple at -5% versus the average which seems well within the standard deviation.

The panels are definitely not clipping, it seems like the overall curve is just slightly lower. I do notice after having gone through the daily data for that time frame over the last 3 years that my production does seem to drop about 5% during week 3 vs week 1. I think this may just be a case of several small changes adding up to what appeared at first glance to be a difference related to the inverter change.

I'll keep an eye on it, but I think it was just a fluke. Thanks again for all the ideas!

[J.P.M.]

Thanks for all of the input. Some additional information - Things have gotten cloudy in the last couple of days so comparisons are difficult, but prior to that we had virtually the same conditions for 3 weeks. Full sun, no clouds for the entire day(s), but the temps are about 10F higher which probably accounts for most of the discrepancy. Week 1 was the old inverter, week 2 was no inverter, and week 3 was the new inverter. System uses optimizers, all are paired and all panels are producing. All panels face due south with no shading all day. At the panel level most of the panels produce very similar power, with a couple them +5% and a couple at -5% versus the average which seems well within the standard deviation.

The panels are definitely not clipping, it seems like the overall curve is just slightly lower. I do notice after having gone through the daily data for that time frame over the last 3 years that my production does seem to drop about 5% during week 3 vs week 1. I think this may just be a case of several small changes adding up to what appeared at first glance to be a difference related to the inverter change.

I'll keep an eye on it, but I think it was just a fluke. Thanks again for all the ideas!

I'd still call the installer and/or send him a copy of this thread. Things are under warranty and you have what looks like legitimate concerns or at least legitimate questions. Where's the harm ?

[Undebt]

J.P.M., I probably will end up doing that, but I want to try to verify myself whether there really is an issue as the installation company is not overly responsive to begin with, and I want to make sure there is in fact a problem that I can quantify before trying to rattle their cage.

[PugPower]

I don't know if this helps, but I have 6.7kW PV system which is hooked to a Solaredge SE6000HD Wave inverter. A few weeks ago I was averaging about 44kWh a day. Since then the outside temps have risen 5-10 degrees and now I am averaging about 41kWh a day. A difference of about -7%.

[J.P.M.]

I don't know if this helps, but I have 6.7kW PV system which is hooked to a Solaredge SE6000HD Wave inverter. A few weeks ago I was averaging about 44kWh a day. Since then the outside temps have risen 5-10 degrees and now I am averaging about 41kWh a day. A difference of about -7%.

That's a lot of decrease to be accounted for by amb. air temp. effects alone. Less wind ? Lower P.O.A irradiance ? Without instrumentation, it's impossible to est.

[PugPower]

Agreed JPM. I was just relaying that increased ambient temps is definitely one factor which contributes to decreased production. You are right though, there are other factors to consider as well, they are just not as easy to calculate.

[theoak]

We are running away from the sun now, so after a full week it would make sense for numbers to drop compounded with additional heat.

[J.P.M.]

We are running away from the sun now, so after a full week it would make sense for numbers to drop compounded with additional heat.

That may/may not be the case, depending on location and array orientation and due to the solar geometry changes being the smallest closer to the solstices, probably small enough to be ignored.

[theoak]

That may/may not be the case, depending on location and array orientation and due to the solar geometry changes being the smallest closer to the solstices, probably small enough to be ignored.

We are almost 1.5 months past the solstice. We are farther from the sun than we were a week ago. That is going to have an impact. We will have to agree to disagree.

[J.P.M.]

We are almost 1.5 months past the solstice. We are farther from the sun than we were a week ago. That is going to have an impact. We will have to agree to disagree.

Agree or not as you wish. My guess is you don't have enough knowledge or in formation to discuss the matter intelligently.