Tesla Wall Connector

[aesculus]

To add evidence to this, when you query the API, the following values are visible for the operation mode:

{
"real_mode": "autonomous",
"backup_reserve_percent": 33.5,
"freq_shift_load_shed_soe": 90,
"freq_shift_load_shed_delta_f": -0.32
}

The "freq_shift_load_shed_soe" changes when you change the off-grid EV charging reserve. This is how the gateway can "communicate" with the EV when off-grid.

Help me out here a bit: When the PWs want to reduce the output of the inverters they will RAISE? the frequency? And when they want to reduce the Tesla cars draw from a power source they will LOWER the frequency?

So it's not just the frequency change, but whether it's raised or lowered? The industry supports the inverter model, but the lowering feature is unique to Tesla?

Supported Versions​

• Powerwall: 1.46+
• Tesla Mobile App: 3.10.2+
• Model 3/Model Y – North America: 2019.40.1+
• Model S/Model X (2014 and later) – North America: 2020.32+
• All Tesla Vehicles in Other Regions: 2020.40

 

[cwied]

Help me out here a bit: When the PWs want to reduce the output of the inverters they will RAISE? the frequency? And when they want to reduce the Tesla cars draw from a power source they will LOWER the frequency?

So it's not just the frequency change, but whether it's raised or lowered? The industry supports the inverter model, but the lowering feature is unique to Tesla?

Supported Versions​

• Powerwall: 1.46+
• Tesla Mobile App: 3.10.2+
• Model 3/Model Y – North America: 2019.40.1+
• Model S/Model X (2014 and later) – North America: 2020.32+
• All Tesla Vehicles in Other Regions: 2020.40

I’m not an expert, but the lowering is by a small amount so I’m guessing most non-Tesla equipment would ignore it. They have to lower rather than raise because otherwise the car wouldn’t charge when the gateway is curtailing solar. I assume the limit for the reserve setting is 90% so it can’t overlap the range for curtailing.

 

[phsoccer]

There are two different things being discussed here...

1. Charging from excess solar when OFF GRID.
2. Charging from excess solar under normal operation.

When the OP stated:



I made the assumption (which I know, assume and all that) that point 2 is what was being discussed. Point 2 (charging from excess solar under normal operation) is not available yet.

Point 1, charging from excess solar when off grid, is an available selection in the tesla app, if the wall charger is backed up. Exactly how they accomplish it, I am not sure, but it is a setting that can be made. This is really only so that you can keep your solar producing and not drain your powerwalls when off grid.

Many of us are excited to see when tesla finally makes "point 2" available, because off grid operation is not the majority of the operation of our systems, for most of us. Its not available yet though.

I have the Stats app and supposedly you can set it to only charge on excess solar, but it only works for 1 day and then resets, plus you have to estimate how much your house uses so it knows how much excess solar there is. I have not tried this yet, but will test it when I get back home. This is a new Stats app feature.

 

[SageBrush]

Help me out here a bit: When the PWs want to reduce the output of the inverters they will RAISE? the frequency? And when they want to reduce the Tesla cars draw from a power source they will LOWER the frequency?

Capacitive reactance is inversely proportional to frequency, while inductive reactive is proportional to frequency.

Is the circuit predominantly inductive (coils) or capacitive ? I'll guess capacitive

 

[aesculus]

Capacitive reactance is inversely proportional to frequency, while inductive reactive is proportional to frequency.

Is the circuit predominantly inductive (coils) or capacitive ? I'll guess capacitive

This is not as much about power as sending a signal to the car (and inverters) to back off, using the home frequency shift as the indicator of how much.

We were all familiar with the technique to increase the frequency to tell the solar inverters to back off, but now we see that for awhile now, Tesla cars have been monitoring the AC frequency too. And when they see something below 60 Hz, they start to back off, regardless of what is set in the cars charging power setting.