It's a custom app that
@Darwin created to run on either SmartThings or Hubitat smart home hubs. Do you have either of those?
I found the Time Based modes don't operate quite the way I want...they don't seem to be designed for plans with flat solar export rates and demand charges (I am on Saver Choice Max plan with APS). So I toggle back and forth between Backup Only mode (with Storm Watch enabled) to prioritize charging the powerwalls during off-peak periods, and Self-Powered (with Storm Watch disabled) to avoid pulling from the grid during peak periods with demand charges. This is scheduled and automatically executed using the built-in Rule Machine app on my Hubitat hub, taking into account weekends and off-peak APS holidays.
Tesla Powerwall Manager app for SmartThings (and Hubitat) Hubs - DarwinsDen.com
In my case, during off-peak periods, I want solar to prioritize charging the batteries first, so they are full when the peak period starts at 3pm. After the batteries are full, solar powers my house, then any excess gets exported. Backup Only mode accomplishes this.
During on-peak periods, I want to pull zero from the grid. So the house runs first off solar, then pulls from the batteries if solar is not enough. If there is excess solar, it will recharge the batteries first, then export whatever's left. Self-Powered mode accomplishes this.
So far it's worked perfectly. During the hottest days here with lots of A/C usage, I am ending the day with around 30% remaining in the PWs. Cooler days like yesterday I ended with 75% remaining. This is with a single A/C unit and 2 PWs.