New inverter for old 2.6 KW system

[road glide]

They attach to line one and two utilility grid supply because USA is split phase system.
But I am curious with SMA sunny Boy 41 that new features have been introduced which would be sweet. They have rapid
supply shutdown, 2k off grid AC power option, monitoring the system through the internet, Etc.
I'm hoping they have zero export has an option in their programming under grid management. But I don't know yet because I have not received my new inverter

 

[FresnoFlats]

PG&E monitors your meter frequently. It reports your usage hourly, but the meter probably records it much more frequently than that. If as road glide thinks is true about PG&E charging for either direction (without a net metering agreement), then I think you could easily get charged for any few minutes where your usage drops down and the solar system is sending power to the grid. I would go out and look at my meter when this would be happening on my system, but the lcd panel is sun baked and I can't see a thing on it!

What Ampster says makes sense to me. The inverter needs a way to read the instantaneous house load to make sure it never exceeds it. PG&E is on this, they don't just look at monthly or annual totals. Here is a graph from PG&E of our hourly use.



This graph shows that they report fractions of KWH per hour.

Here is the graph of the SunnyBoy output for the same day.

 

[road glide]

My biggest problem is I am waiting for the unit and trying to do research of what to do and what not to do. Going back to the beginning, you have the same inverter I am getting...So I was intrigued,
Googling "solar" "smart meter", etc, etc....I saw stories where some residential users in other states were trying to opt out of smart meters.
There was even an News article about folks in some metro area in apartments that had removed their smart meter and put conductors in the terminals to steal electricity....How stupid, electrocution, fire not to mention theft.....You should see some of the pictures....You can't fix stupid...LOL

On the sunny boy graph, what was your total production....I see it began slowly around 8am and looked like it dropped of at 6pm. I know you have 20 panels of 120w. I think I see it....looks like almost 2kw at noonish....

 

[FresnoFlats]

In the SunnyBoy Graph above, there is a weird blank space at 8:45 to 9 am. I think that is a reporting glitch as there is no corresponding jump in the PG&E use graph. The odd dip between 4:10 and 4:30 pm is when a shadow first hits one panel. The shadow steadily increases over time, but somehow the inverter is compensating and brings the output back up. By 5 to 5:30 shadows from trees are hitting quite a few panels.

 

[FresnoFlats]

I am hitting right about 12 KWH per day. The peak production has been 1700 to 1800 watts. So the panels are actually putting out 90 watts at the most.

 

[FresnoFlats]

With the new inverter, it has been very educational seeing how the output fluctuates with different conditions. The old inverter only had an LCD window on the inverter itself that showed instantaneous output and daily total, I think. It was not easy to read, so I took photos of it occasionally but have not looked them up since. The SMA Sunnyboy, of course connects to our home network and I can see instantaneous, hourly , daily and monthly values on my computer screen. That makes it much easier to see what factors are effecting the output; when shade is reaching a panel, the time of day, clouds, etc.

On good days this summer, our peak panel output was typically about 1850 watts with occasional peaks of 1900. The system was originally rated at 2600 watts, but at 18 years old, I was just happy to see it working at all. The typical daily output was around 12.5 KWH. With summer PG&E rates, that is about $4 a day of electrical output. On really smoky days the output was occasionally as low as 5 KWH.

With shorter days, lower sun angles causing more shade, the typical peak output has been around 1500 watts with the daily output around 7.5 KWH. Now that we are starting to get winter cloud cover output is really low. I am curious to see how low the output will be when we get our infamous Tule Fog here in Fresno.

Yesterday, however, we had our first rain of the season. Output was naturally low. Around noon, however, the clouds became patchy, allowing brilliant sunshine through a nice clear sky. The inverter reading was 23300 instantaneous peak output! The peak 5 minute reading was 2.22 KW. I am happily amazed. These 18 year old panels still have 85% to 90% of their original capacity given good conditions.