Hi, new powerwall and solar: I searched the forums, I couldn't find an updated answer (10/2022) to this: how to disable vehicle charging during grid outage? Searching the internet it seems like it should be under settings for the solar but I see no such options even though 2 tesla vehicles are also in the account. Did they remove the option?
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how to disable vehicle charging during grid outage?
- Thread starter cybergates
- Start date
Its under Settings -->EV Charging, however, its very (very) common for certain options to not be there in the tesla app on new installs. It can take a week to ten days sometimes for all options to show up in your tesl account.
The setting I am referring to above doesnt disable charging the car when off grid per se, it sets a limit on how far the car can drain the powerwalls to charge during an outage. Pretty much the same thing, but its not a "yes / no charge the car during outage" setting, its a "save this percentage of power for home use during power outage" setting.
You can't actual set this to 100% as the highest value allowed is 95%. No idea why this is the maximum limit. My only thought is that it would allow more usage of solar during an outage when the Powerwalls get to 100% and the PV would need to be shutdown, so this would increase the load.
I have a suspicion this is done with a frequency shift. The frequency shift to get the solar to back off would conflict with the frequency shift to turn off charging if this were the case. The reason I think this is because the API on the Powerwall reports a "freq_shift_load_shed_soe" value that's the same as the cutoff I set with a "freq_shift_load_shed_delta_f" set to -0.32. The frequency shift for solar curtailment is in the positive direction.
Interesting, where did you find information that a frequency shift controls the EV charging rate? The closest that I can find is this statement:
This implies that something else is in play other than control from a Tesla server. The supported list includes the Powerwall, App, and Model 3/Y/S/X, but the wall chargers are not listed, so it must be something between the Powerwall and Tesla EV. The frequency seems to be a strange choice.
I didn't find an explicit statement, but if you access the local API at <powerwall ip>/api/operation, this is an example of the response:
JSON:
{
"real_mode": "autonomous",
"backup_reserve_percent": 36.349999999999994,
"freq_shift_load_shed_soe": 90,
"freq_shift_load_shed_delta_f": -0.32
}Also, I think the frequency shift is an easy, low-tech way for them to do this control since they already use frequency shifting to control PV generation.
