Solar Meter Reading Interpretation Question

When I look at my solar production using Sense, it looks like the solar production is getting clipped at a max of about 6500 watts (See images below). My solar is a 7.35kw Sunpower system using micro-inverters.

How do I interpret this? Are the panels reaching max capacity? For a 7.35kw on a sunny day, is that a reasonable max output? Or, is the system clipping because something is not correctly sized or some other configurational problem?

Thanks for any insights.



@sense23 , yup something is clipping. Either the Sense metering or the micro inverters themselves. Do you have a second reading from the microinverters ?

i have micro inverters that are 250w ea and my panels are 325 ea. They said I have a 9.1kw system, but get 6500w and have the same results as you. Most likely your inverters are clipping and you are basing your expectation at the total system number and not what your inverters can really do.

aka your inverters are undersized. When I got my system, it was the only size avail from the mfgr. I have looked into upgrading the inverters but its not worth the expense for the small gain. in 20 years when its time for system replacement there will be more and other options.

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I have 8.64 kW rate Sunpower system with 320 W panels. I see clipping when observing the individual panel outputs and that is consistent with the micro inverter specs. I did some reading up on this and found that while you could have large capacity micro inverters the cost would go up a lot for a marginal benefit in regaining the otherwise clipped output. Clipping, for me, started about 3-4 weeks ago, and I estimate will last for a total of about 90 days around the summer solstice (45 days each side).
For comparison, my 8,640 W system seems to peak (with clipping) at around 7,600 which is a 1.13 ratio, which is virtually identical to your ratio of 7,350/6,500

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Thank you all.

@dolfs - thank you for the detailed info. I have the 350W Sunpower panels, and I just open up the installation specs, and they were installed with 327W micro-inverters. I am glad to hear that the ratios are similar, that essentially proves to me that the clipping is due to the micro-inverters being undersized.

@danderson - thank you as well, you were correct in your diagnosis. I did not have any expectations, I just wanted to make sure the clipping wasn’t due to a problem (I recently had to switch out a suspect circuit breaker which kept tripping, and thus started looking more carefully at the data – so I wanted to make sure there wasn’t some other problem).

@kevin1 – unfortunately, one of Sunpower’s biggest deficiencies is that they don’t give you access to microinverter data through their portal, only the totals. I have seen people building raspberry pi devices to intercept the data being sent to the servers to get the necessary readings, but I haven’t had time to implement such a solution yet.

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Yup. I built the Raspberry solution and have full and detailed per panel/inverter data. Total cost $35. I have a document published about it. Let me know if you want the link.

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Here is an example (through HomeAssistant) presenting power output data (from today) from a single group of 6 panels (each panel different color).
CleanShot 2022-06-09 at 21.55.36
and here is another example with temperature data from a group of 12 (which includes that first group of 6).
CleanShot 2022-06-09 at 21.56.44

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@dolfs wow… yes I was indeed referring to your solution and your website, but I had not connected the dots. I already have it bookmarked :smile: Thank you for sharing all of it. I just need a break from my work schedule to sit down and play around with it, hopefully maybe late summer.