Panel Output est drop after 6 years

Questions
#1

My system has 16x 195 Watt Panels (3.120kw). With my original inverter (Xantrex GT 2.8kw) for a large portion of the day I would see a near flat line of 2.8kw. That inverter died after 3 lightning strikes to the house a few months back and was replaced with a Fronius Galvo 2.5kw. Since uploading data here and also to a home brew version on a laptop similar to this site I have noticed my max output on these past two CLEAR days was barely over 2300watts and also there was no flat line or output, more of a rise and fall curve, That is about 25% or more performance drop. And being a smaller inverter I would have expected to see a slightly longer flat line of output.

These past two days have been clear and hot, and I know heat makes panels drop performance and have seen that at an outside temp around 27c the drop is sharp. My panels are ground mounted on adjustable frames, panels are clean and as cool as they can be with 6-10 feet of space between the panels and ground (so plenty of air flow).

Is it normal in a sense to have 25%+ drop in 6 years. To me sounds excessive but I don’t really know. Or should I be looking at something else with the system.
https://imgur.com/UwutnY6

Not sure how to attach a picture here so supplied a link

#2

Are you saying power has dropped off after 6 years gradually OR since the Inverter replacement following lightning strikes.
2 different things.

Yes output can drop due to a few factors, BUT you will not see the full 3120w when operating normally. 2800w sound close.
From time to time with cloud edge effect and very cold air you can even get over the 3120 but only for short busts and it will soon drop back to 2800 or so. 300 watts drop following lightning strike would make me look elsewhere.
When Inverter was changed did they check panels and diodes etc for damage?
Is its efficiency the same? etc

See my graph below for example:
https://pvoutput.org/intraday.jsp?id=1335&sid=4380&dt=20171130&gs=3&m=0

Baz

#3

The installers tested the open circuit output but didn’t inspect each panels diodes.

Cloud effect I see occasionally peaks around 2800w for a short time, but on full sun no clouds peak is around 2300w. But the peak is only for a very short time of the day with the new inverter (say mid-day). I have looked at other local system around PVoutput and it seems common on the same days where the peak is lower but a nice curve to the chart. One system local has 7kw of panels on a 5kw inverter and is getting the peak output in a flat line for much of the day. So makes me think I just need more panels also. 2nd hand panels seem cheap enough, so I might think of doing that with the remainder of roof space or add to the sides of my ground mounted frame/panels.

Old inverter was 2.8kw, New one is 2.5kw.

#4

best day in 2016 might of been December 15th at 24.12 peaking at 3312w

Best day in December 2012, December 21st 2012 you generated 23.26 peaking at 3060w

On December 11th 2017 Generated 20.9 peaking at 3220w.

not sure I see any drop.