How to program Backup Percentage charge?

How to program Backup Percentage charge?

My utility in Arizona calls peak hours noon to 19:00, and power is about 5x more expensive during that period. By setting my backup percentage at 100% during off-peak hours and, say, 20% during on-peak, I can get the Powerwall to charge during the morning sunlight hours, and provide power to the house in the early evening after sundown. This would seem to abide by the somewhat silly requirement to not charge the Powerwall from the grid, and still allow me to derive some benefit from the batteries.

The problem is: I have to do this EVERY day, MANUALLY, and even guess at what time to make the change on the app since it seems to take a variable time for the change to be transmitted to the system.

Dear Tesla: Please make your app more functional!


rfactor | 16 marts 2018

Update on this question: I've tried doing it manually for the past couple of days and found another glitch, even with the procedure detailed above. Apparently if you set the Powerwalls for 100% backup the charge rate is limited (at least for three batteries) to 5kW.. I want to send ALL my solar power to the batteries during off-peak hours until they are fully charged.

The app won't let me make that decision, at least not easily by checking the full backup box. Due to the sloth of the app's "customization" control, it's hard to experiment effectively. I'll try changing the numerical input and see if that works better. Meanwhile,

Dear Tesla: Please make your app more functional!

Marleenyuli | 17 marts 2018

my understanding is it takes up to 1 hour for the change from backup to self-prod to take effect; essentially killling one hour of potential self consumption during offpeak

The way we plan is go to sleep and hit the backup 100% mode and the grid will hopefully charge to 100%. Today is day 1 for us and 20% charge at noon and going up with the sun. It'll be interesting to see the consumption this evening and then will switch to backup mode 100% tonight before bed to see what happens. -- my HOPE is that it will charge up to 100 on grid power.

rfactor | 17 marts 2018

Unless you have a different software app, this won't work. The problem is that the Powerwall will not charge from the grid at all, due to software restrictions that Tesla has not yet removed. You can only charge from solar power, and it would seem that if your utility's peak charges fully overlap your sunlight hours the Powerwalls are useless except for backup purposes.

I'm continuing to experiment with my time-shifting strategy. More later.

cwied | 18 marts 2018

If you're willing and able to do a little technical set-up yourself, you can use the gateway's local http interface to avoid the lag on switching the percentage. I set up a small server that switches me from 100% to 50% reserve and back by http request. By port-forwarding to this server I can now use IFTTT to automate the TOU switching as well as participate in OhmConnect's demand-reduction program. It's kind of Rube Goldberg right now, but it works well enough for my purposes.

rfactor | 18 marts 2018

Hi, cw_tesla. Thanks for that hint. I have no idea how to access the gateway. It's connected to my local network, but I just assumed it's encrypted and only talks to the mother ship. If I can give it immediate commands via http and adjust the backup percentage that should solve the problem.

I've done a "review" of the Powerwall ( ) which explains the issue more completely than I have here. I'd love to be able to add a simple fix!


cwied | 19 marts 2018

If you have the technical know-how to use the debugging features in a browser, turn it on and go through the Tesla setup wizard by navigating to the gateway's local http interface. Also do a search on this forum for the REST interface. The setup wizard includes the ability to set the backup percentage. You can just use the same http request to automate it.

rfactor | 21 marts 2018

Thanks again, CW. I could probably figure this out, but I just heard from my customer contact that they are “rolling out” an app update that will do what I need. Not sure why it has to be rolled as opposed to being put on line today, but I’d rather exhibit patience than make extra work for myself. I’ll be back here if it doesn’t show up soon.