Powerwall behavior during outage with 2012 Model S

[Bubbles]

I recently signed up to add 3 Powerwalls to my home and am trying to decide whether to put the EV charging circuit on the panel with loads backed up by the Powerwalls. I see on the Tesla site that the smart features for controlling vehicle charging during an outage are only supported for cars US MS manufactured in 2014 or later. So we should be fine for our 2015 MS, but the 2012 Signature MS seems to not support this feature.

Does anyone know what happens in practice when an older MS is set to charge during an outage? Does it just plow ahead and drain the battery? If so, are there work-arounds such as installing a wall charger? We currently have the mobile charging cable plugged into a 50A outlet.

I realize I could install a second outlet and only power the 2012 MS from the grid loads, but it was several $K to run the first outlet to the detached car port and I am not keen to have a second line run.

Thanks for any info/advice!

 

[arnolddeleon]

There are theoretically several different ways to work around the situation.

First and cheapest is assume that you will get notified and awoken by the alert from app says the grid is down and you manually stop the charging/unplug the offending car. It's likely not that horrible if the batteries "emptied". They won't really be empty, they will shutdown, saving a small amount so they can check to for solar later. So if this happened while you were asleep you will wake up to no power but you can easily remedy when your PV starts producing.

The second option is use something like Home Assistant and the integrations for the Powerwall and Cars. Build an automation that stops the car charging (assuming the 2012 has the option for stopping remote charging) when the grid is down. You can basically recreate Tesla's automation.

If the car can't stop charging via an API you can add an EVSE that has an API you can call to turn it off.