Tesla Powewall's Vehicle Charging when Off-Grid setting. Can't set to 100%

[notsure11]

I have two Tesla Powerwalls w/ a whole house backup and without solar. On my Tesla app - Settings menu, there's a setting for Vehicle Charging when Off-Grid. I want to set the threshold to 100% (i.e., no car charging at all when the grid is down). But when I set it to 100% by moving the slider far to the right, it doesn't stick. The next time I go back to Settings menu, it's back to where it used to be. I was able to get it up to 95% though. Is 95% the max you can pick?

https://imgur.com/a/RyAmxYX

 

[jboy210]

My guess is the 5% reserve is to ensure there is enough power to run the electronics in the Powerwalls, and also not run the Powerwall's batteries too low which can harm their lifespan.

 

[EVRider-FL]

My guess is the 5% reserve is to ensure there is enough power to run the electronics in the Powerwalls, and also not run the Powerwall's batteries too low which can harm their lifespan.

I think the OP was saying they can set the Powerwall reserve to at most 95% for vehicle charging off grid, so the Powerwall SOC isn't the problem.

 

[Zinc_Saucier]

Just tried to change mine to 100% home use, but when I go back into the settings menu it has dropped down to 90%. No idea what’s going on, but another datapoint

Edit: well now that I posted that it would only go to 90%, it now goes to 95%… maybe with this edit it will allow for 100%

 

[notsure11]

I think the OP was saying they can set the Powerwall reserve to at most 95% for vehicle charging off grid, so the Powerwall SOC isn't the problem.

That's correct -- when the grid is down, I don't want my car charging off of the Powerwalls at all. With my current 95% setting, I think the car will charge until the Powerwalls drop down to 95% and then stop. Probably not a big deal, but just weird since UI suggests I should be able to set it anywhere between 0 and 100.

 

[jhn_]

That's correct -- when the grid is down, I don't want my car charging off of the Powerwalls at all. With my current 95% setting, I think the car will charge until the Powerwalls drop down to 95% and then stop. Probably not a big deal, but just weird since UI suggests I should be able to set it anywhere between 0 and 100.

Yeah it’s weird and been this way since they introduced the feature and more prominent with the new 4.0 version of the app.

Maybe it’s a way for them to keep a buffer so they don’t have to turn off solar generation in a grid down event when Powerwalls are getting nearly full? Since it’s not 100%, then they can still send excess power to the car and hover the Powerwalls at 95%? Just speculating. They could document or illustrate that better though if it was the case.