What's actually drawing current from my 2020 Tesla Solar Panels/2xPowerwalls?

[grubT_mc]

So, when Tesla installed our 24-panel 7.68kW array + 2 Powerwall2s, they appear to have disconnected all the circuit breakers from our original 125A service panel (all are in the OFF position and our electrical stuff works), EXCEPT the 2x70A breakers for the 2xTesla Wall Connectors (previously the electric dryer circuit), and 2x40A for an electric stove (active - tested at the outlet, but not being used as we were/are using a gas range, but plan to switch to an induction range this month).

When we're charging either/both M3s, if the solar output + Powerwalls makes it to 12-14 kWh nothing comes from the grid. If the solar output + Powerwalls <12-14 kWh, the difference is made up from the grid.

Anyway, it occurred to me that maybe the 2x40A are not actually on the solar side (I have this memory that the electrician said something like that during the original install), and if we start using an electric range all of the current would come from the grid? Is that even possible?

Thanks in advance for any thoughts...

 

[grubT_mc]

Sounds like you have a partial backup. All your loads must come from a new panel Tesla installed except those two 40A for the stove. Yes using those 40A will come from the grid.

Thanks. Shoot...

 

[jhn_]

Thanks. Shoot...

I just deleted my post since I realized it was wrong.

I overlooked that you said your wall connectors draw from solar and battery and they are in the same panel as the stove. Every breaker in the same panel will draw power the same. So your original panel got turned into a sub panel and there is also another panel someplace where they moved your other loads.

It’s possible they created this sub panel out of your original panel so it’s is for non-backed up loads. That would make sense with two Powerwalls and two EVs that could drain those batteries in no time. But without a little bit more info it would be hard to say accurately.

 

[grubT_mc]

I just deleted my post since I realized it was wrong.

I overlooked that you said your wall connectors draw from solar and battery and they are in the same panel as the stove. Every breaker in the same panel will draw power the same. So your original panel got turned into a sub panel and there is also another panel someplace where they moved your other loads.

Thank you for the update! That was my thinking this morning when I checked the wall connectors breakers. I can relax, and set up a plumber to cap off the gas line behind the range.

 

[grubT_mc]

One more question:
We want to switch from gas to electric: heat pump clothes dryer and a heat pump mini-split. Both would require new 220/240 wiring. I believe a service panel upgrade to 200A is necessary also. I was reading threads questioning panel upgrades before or after Tesla solar install (and the answers all say before!) but there doesn't seem to be any solutions about our situation where the installation is a done deal. Is it possible to do a service upgrade with an existing Tesla Solar installation?

 

[ewoodrick]

One more question:
We want to switch from gas to electric: heat pump clothes dryer and a heat pump mini-split. Both would require new 220/240 wiring. I believe a service panel upgrade to 200A is necessary also. I was reading threads questioning panel upgrades before or after Tesla solar install (and the answers all say before!) but there doesn't seem to be any solutions about our situation where the installation is a done deal. Is it possible to do a service upgrade with an existing Tesla Solar installation?

Depending on where you are and a number of other factors, upgrading the panel can range from only a lot of money to impossible. Yes, impossible is an answer if the utility doesn't have capacity for it.

 

[cwied]

Electricity can flow both directions in wires. The only time the location of your loads matters is when the power is out and the gateway has disconnected from the grid. If the loads are on the grid side of the gateway, they can't be powered by solar/Powerwalls during a grid outage.
When the grid is up, whether the grid is used or not depends on whether your solar and Powerwalls are producing enough power for the load or not. The gateway controls Powerwall output to offset your loads according to the settings you entered in the app.
It's easier if you think of it as "electricity flows to where it's needed" rather than "electricity is directed to where it's needed." If a load is using power, it will flow from where it's being produced, whether that is the grid or your system.

 

[grubT_mc]

Electricity can flow both directions in wires. The only time the location of your loads matters is when the power is out and the gateway has disconnected from the grid. If the loads are on the grid side of the gateway, they can't be powered by solar/Powerwalls during a grid outage.
When the grid is up, whether the grid is used or not depends on whether your solar and Powerwalls are producing enough power for the load or not. The gateway controls Powerwall output to offset your loads according to the settings you entered in the app.
It's easier if you think of it as "electricity flows to where it's needed" rather than "electricity is directed to where it's needed." If a load is using power, it will flow from where it's being produced, whether that is the grid or your system.

Thanks for that clear explanation, especially the last sentence. I honestly don't know why I didn't think of that, I spent 8 years as an electronics technician in the Air Force. I'm guessing it's age, both mine and the amount of time since I was discharged.

Anyway, we can now comfortably move ahead with our moving to less gas and more electricity. Finding out if we can up our service to 200A is the next hurdle.

Thanks again!

 

[grubT_mc]

Depending on where you are and a number of other factors, upgrading the panel can range from only a lot of money to impossible. Yes, impossible is an answer if the utility doesn't have capacity for it.

Thanks! PG&E wouldn't pass up a chance to collect more money, I'm guessing

 

[ewoodrick]

Thanks! PG&E wouldn't pass up a chance to collect more money, I'm guessing

That's a yes and no question, would they take extra money? Yes!

But if they have to run new power lines or upgrade a transformer to support a single request. Then no.

And that is exactly what has happened to some Tesla owners trying to install 60A outlets. They needed to upgrade their panel. They needed more service, which required another transformer (because the existing one was maxed out). And I have no idea if new power lines to the neighborhood was ever determined, because they are going to charge you too much to replace the transformer.

 

[grubT_mc]

That's a yes and no question, would they take extra money? Yes!

But if they have to run new power lines or upgrade a transformer to support a single request. Then no.

And that is exactly what has happened to some Tesla owners trying to install 60A outlets. They needed to upgrade their panel. They needed more service, which required another transformer (because the existing one was maxed out). And I have no idea if new power lines to the neighborhood was ever determined, because they are going to charge you too much to replace the transformer.

When we put in our Wall Connectors the electrician found (from PG&E and the county) that: 1) He could upgrade the 100A service by replacing the 100A breakers with 125A. Also, since the M3 maxes out at 48A he could install the 2 Wall Connectors through a 2-breaker 70A line. Charging 1 car can get 48A, 2 cars simultaneously can get 24A to 28A each.

Several houses around here have >125A service. If it turns out PG&E's transformer is maxed out, I guess we'll not be able to switch to most/all electric until they decide to replace the transformer since I'm not paying any more for their infrastructure capital improvements than they suck from my wallet via their exorbitant rates.

 

[ewoodrick]

I'm glad that you could at least get the chargers in. Too bad on the remainder.
It's kind of a generic issue for 100A panels and smaller.
It's always a possibility for 200A panels, but lower occurence.

While it was not a criteria when I bought this house 2 years ago, I've got 400A service now. And the damn panels are nearly full!!!
It was built as an all electric house because there is no water or gas on the road.
I'm starting to see a number of houses being built with 400A service (2-200A panels), even around 3,000 sqft. We just use more electricity today than 50 years ago.

 

[Vines]

Smart chargers are coming, and Tesla has one available to select markets.

Its is basically a smart charger that can be configured to reduce draw, as the service demand approaches its programmed limit. THis is certainly the future to avoid the service upgrades, and you will only charge at full rate overnight.

 

[h2ofun]

Smart chargers are coming, and Tesla has one available to select markets.

Its is basically a smart charger that can be configured to reduce draw, as the service demand approaches its programmed limit. THis is certainly the future to avoid the service upgrades, and you will only charge at full rate overnight.

Boo, and I just bought 5 wall connectors

 

[Vines]

Boo, and I just bought 5 wall connectors

The hardware is the same from my understanding, just additional software and a Neurio to measure the load on an incoming conductor.

 

[jgleigh]

I think @h2ofun needs a microreactor to really up the power!

 

[h2ofun]

The hardware is the same from my understanding, just additional software and a Neurio to measure the load on an incoming conductor.

Cool, will see down the road if installing this stuff has any value for me. So far, I have no plans to power share if more than 1 EV needs to be charge, will just deal with it manually.

How do you like your Model Y? I love it has a great toy. Going to see if I can do a trip with a planned supercharger and live

 

[Vines]

Cool, will see down the road if installing this stuff has any value for me. So far, I have no plans to power share if more than 1 EV needs to be charge, will just deal with it manually.

How do you like your Model Y? I love it has a great toy. Going to see if I can do a trip with a planned supercharger and live

My model y does everything better than my 3, except drive very fast.

I took the 3 for a total of 40k miles in road trips, including once across the country to DC and NY. With the longer range and larger vehicle, I cant wait for our next road trip in the Y, its a great family car.