Help on 14-50 install with existing solar

[kpinthebay]

Hello, I need some electricians help here because I'm between a rock and a hard place. I had Tesla solar and powerwall installed a few months back. After the install, and after PTO, I had a NEMA 14-50 outlet installed for my Model Y. Every circuit in my house, except for A/C is backed up by the PW on a separate subpanel. The A/C remains on the main panel and is fed by solar when available. All installs performed by licensed electricians.

My problem is after the 14-50 install, I noticed the daytime spikes from charging the MY at noon was not showing in my Tesla app. I went into my utility website and noticed I was pulling from the grid during clear daylight hours when I'm charging. I concluded that my charging off the 14-50 was not being powered by solar. The circuit is located next to the A/C circuit in the main panel.

Problem is my electrician can't figure it out. And I can see his point as I would have expected anything in the main panel would be covered by the solar panels. I have a hell of a time contacting someone at Tesla that knows the answer to my problem. Thoughts??

 

[miimura]

You have to look at the placement of the Grid CTs and how the Gateway is fed from the main panel. When my Powerwalls were first installed in 2018, the Grid CTs were placed on the input of the Gateway switch from the factory. The Tesla app was completely blind to all loads in my main panel. I opened a case with my third party installer and they moved the Grid CTs to conductors between my main breaker and the main panel bus. My Gateway is fed by a 125A breaker in the main panel.

 

[getakey]

what rate plan are you on? Surprised you are charging mid-day

 

[kpinthebay]

what rate plan are you on? Surprised you are charging mid-day

I'm transitioning to the EV plan, but when it's high noon I'm sending too much back to the grid and was hoping to take advantage of my sparkly new solar panels.

 

[getakey]

how can you send too much back to grid?

 

[israndy]

Moving the CTs will probably make the graphic look like you want, but I am surprised that you are seeing a spike from your utility if you really are generating as much power from Solar as you think. I have a 7.2kW system and I charge my Tesla via a 110v outlet as if I pull much more the car is eating ALL the solar.

If you are trying to charge your car at noon and still see a spike from the utility you should probably charge at night, when the rates are low. And moving the CTs is not going to be that useful when you are charging at night. The CTs are to show you the house demand and the solar-production as relates to your Powerwall.

 

[israndy]

how can you send too much back to grid?

If you are not on Net Metering (like I'm not for example) I get 7¢/kWh but you pay 28¢/kWh. So it's better to put that power into a battery to use later rather than sell it to the power company so cheap.

It's all free money at this point, as my solar system is pretty much paid off, but I still prefer to use an appliance or do something else with the power while it's coming off the roof

 

[BrettS]

but I am surprised that you are seeing a spike from your utility if you really are generating as much power from Solar as you think

The thing is that depending on your usage mode it may be using excess solar power to charge the powerwalls because it thinks that the home isn’t using much power. So the car winds up drawing power from the grid. If the CT’s were in the right place then the gateway would know that there was a high demand from the home and it would send the solar power to the home instead of using it to charge the powerwalls.

 

[getakey]

If you are not on Net Metering (like I'm not for example) I get 7¢/kWh but you pay 28¢/kWh. So it's better to put that power into a battery to use later rather than sell it to the power company so cheap.

It's all free money at this point, as my solar system is pretty much paid off, but I still prefer to use an appliance or do something else with the power while it's coming off the roof

his install was a few months ago. PG&E would have switched him by now I would think

 

[Akikiki]

@kpinthebay, wow, surprised your contractor didn't install the a Solaredge inverter with the EV charging option.