Is this normal?

[Dan203]

I bought a "small" system from Tesla rated at 3.78kW. (12x315W panels) I just turned it on last week. The power output seems to be capped (clipped?) at 2.8kW though. Is that normal? Here is a screen shot of my graph from yesterday...

I specifically bought this system to help offset TOU rates that shoot up from $0.08/kWh to $0.43/kWh from June-Aug 1:00pm-5:00pm. As you can see from the graph the panels are perfectly positioned to generate at that time. But for some reason they've been capped to just 75% their max output. As far as I can tell the inverter is capable of 3.84kW so I'm not sure why it's capped. (Delta M4-TL-US)

Is this normal? Or is something configured wrong?

 

[mongo]

Did they run it as one string or two strings to the inverter?
Edit: probably not a factor.
Double edit: the manual limits single string power to 70% which lines up with 2.8kW on a 4kW system.

1) Un-balance PV input allowed, maximum input power for each MPP tracker is limited with 70% rating power. And total input is limited with 100% rating power

 

[Dan203]

Did they run it as one string or two strings to the inverter?
Edit: probably not a factor.

There is only one pipe going into the inverter from the roof. All of the panels are touching so I assume they're all daisy chained into one big array.

 

[mongo]

There is only one pipe going into the inverter from the roof. All of the panels are touching so I assume they're all daisy chained into one big array.

They could have it wired as two in one conduit.
I updated my question with a line from the manual. The M4 has two peak power trackers. If only one is connected, it would be limited to 70% power.

 

[Dan203]

They could have it wired as two in one conduit.
I updated my question with a line from the manual. The M4 has two peak power trackers. If only one is connected, it would be limited to 70% power.

I have no idea how they wired it inside the conduit. Why would they use a layout that only gave me 70% of my peak power?

 

[mongo]

I have no idea how they wired it inside the conduit. Why would they use a layout that only gave me 70% of my peak power?

I don't think they would on purpose, but in terms of the available data and symptoms it fits the situation.
Other inverters including the M6 could handle the 12 panels as one string so it may have just been a brain fart or miscommunication.
I don't know your level of comfort with electrical, but you could turn off the breakers and open the wiring cover to check.

 

[mongo]

Based on the 315 watt panel data sheets I've looked at, it seems less likely that they would have done it as one string due to maximum voltage limits.
If you have an Android device, you can check the power reading directly from the inverter with an App.

 

[Dan203]

Based on the 315 watt panel data sheets I've looked at, it seems less likely that they would have done it as one string due to maximum voltage limits.
If you have an Android device, you can check the power reading directly from the inverter with an App.

I do, what app?

 

[mongo]

I do, what app?

I may have spoken too soon.
It is supposedly "M tool" per the inverter manual I downloaded online. However, that app does not appear to exist on Google Play anymore. The app that does show up for Delta inverter has really poor reviews.

 

[lucassaugen]

I had the same 2.7 kWh cap and the installers came our and just ran a couple of jumpers and now I'm pushing 3.5kWh+. It only took them like 10 minutes to do it too.