Powerwall Design Feedback

[Autocol]

Hi All,

I am about to start building my backup power system. My batteries should arrive in the next couple weeks and then I am good to go. In the meantime, I have drawn up a diagram of how I plan to connect the system. I was hoping that some of you could take a look and provide some feedback on issues or improvements.

Thanks, Eric.

 

[Autocol]

I just realized I forgot to show the 40-amp breaker in the main panel that feeds the Growatt.

Also, should I put a 30-amp breaker and disconnect switch between the solar panels and the Growatt? I plan to install a PV combiner once I have more than one string so am not sure if they are necessary.

 

[Autocol]

I had some suggestions in another forum thread about using a single heavier gauge wire instead of the default dual 8AWG wires connected to the BMS.

I have also shortened the run to the panels by drilling a hole in the concrete foundation instead of rerouting to an existing hole farther away.

Here is the updated diagram.

 

[Autocol]

I received my busbars and noticed that they say DC only. I then realized that I had had a “brain fart” and was doing the AC side wrong.

I should have been using junction boxes instead of bus bars for combining the AC runs and switched my design to that setup. However, I then realized I was making things more complicated than they needed to be. I have now eliminated the junction boxes and am doing all the runs directly.

The other problem I noticed was that I was grounding the DC current from the solar panels to the AC main panel. I have removed this connection and will ground the solar panels on their own.

One other change I did was switch to a Class T fuse on the positive battery connection.

I am hoping I do not have any other “brain farts” in my design. I would really appreciate if some of you pros out there could take a look at my new design and let me know your thoughts and if I have any more mistakes.

Thanks