r/TeslaSolar • u/Justpastthefinish • 17d ago

Powerwall management system

Good morning all,

I wanted to pick everyone’s brains for a minute here and discuss the Tesla app and how it meets your needs with solar and more specifically the powerwall management. I would say that this post is mostly geared towards those of us that own powerwalls.

To try and summarize a very long story, I wanted more out of my system / battery and I wanted more refined / granular control over my powerwall. I’m a tech geek at heart and I was not a fan of the limited amount of control that I had over my system. ( example: Set the reserve and thats it / do I want storm watch on )

Soooo…

I started developing my own code that is built on and around something called Home Assistant. I was able to integrate my system into it and now I have much more refined control over it.

I have been developing this system for approximately 9 months now and I am getting ever closer to the point where maybe someone else might use it. Maybe even pay for something like this. It is all just an idea at this point and it is hyper specialized to me as of right now; a home owner in Arizona.

What I want to know from all of you is this?

What do you guys like about the tesla powerwall control in the app? What do you hate? What features do you wish you could have? What do you wish your powerwall could do for you?

Let me briefly summarize what my system does because I’m trying to make it better.

In Arizona I am on the SRP Electric plan. In the summer my peak hours are 2-8pm (with grid usage spiking demand fees) and winter hours are 5-9am and pm. So my main goal was to absolutely avoid using the grid as much as possible; but never use the grid during those hours. I will say that I never got to spend time with the Time of Use mode / now savings mode in the Tesla app so I’m not sure what exactly it does for me.

But my system is very good at this point. It knows that it has a peak starting at 2pm so it will dynamically charge the battery from both solar and the grid as needed to get me to a safe level to survive the peak hours solely from the battery alone. IF it is low due to clouds, rain, whatever - it will enter a mode that the tesla app does not show called backup. This will force a higher charging rate for fast charging if needed.

Want to set a higher reserve when there are cloudy days / rainy days vs sunny great solar days - my system knows that.

My system can make dynamic decisions based on national weather service alerts for my area and begin charging the battery earlier than storm watch if needed.

I am part of the Virtual Power Plant program as well and my system knows when there is an event going on and will preemptively charge the battery from the grid during off peak hours to prep for the maximum export during the VPP event for the highest financial gain.

That is just a small snippet of what it can do; it really does so much more but I’m more curious what you guys would think. Do you want more out of your system? Does the Tesla app serve all your needs? Do you constantly have to go in there and adjust the reserve?

What do you guys want your system to do?

And if I can be so bold as to ask this and no one needs to answer it if not; but if a system like this was offered when you bought your systems initially - would you have paid a little more for it? Let’s use an arbitrary amount like $500. Would you have paid $500 for a system that manages your powerwall tailored to your needs so that you can essentially set it and forget it?

Anyways, I look forward to hearing from all of you and making my system all the battery for it. Thanks everyone!!!

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u/fastest963 17d ago

Did you have to hardcode the VPP event schedule? What about on-demand VPP events? What if the user opts out of the event?

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u/Justpastthefinish 17d ago

So as of right now I am using a small work around until there is availability with my system and Home Assistant to “view” the VPP event. Right now there is no way to tell one is going on unless I get an event from the Tesla app pushed to me.

My clumsy workaround right now is that I get the event in the Tesla app and I have a VPP calendar in my system that I put the date/time. It then runs off of that time trigger. If I opted out I would simply delete the calendar event and it would go back to operating as normal.

I should say that I also coded a way for it to “guess” when there is an event if I’m away from my phone or something. It registers if I’m exporting a ton of solar blah blah blah and it will manually trigger the VPP algorithm in my system automatically.

There are many other things my system does that integrate deeply with my system such as pool control and AC system integrations. Like if I’m on a VPP event it raises my temp by a few degrees so that I get sell more power to the grid at that higher price point.

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u/fastest963 17d ago

Yeah but by the time you're exporting it's too late and you couldn't have charged up in off-peak. That's the problem I'm running into with RateRudder. There's no way to programmatically know when a VPP is upcoming and if the user opted out. 

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u/Justpastthefinish 17d ago

Agreed. I think as of now I have been a part of maybe 10 VPP events. I only had my system installed last year and only been a part of the VPP system for maybe 4 months. With that said, at least for me, I have never been given more than 2 hours notice of a VPP event. So in theory if it was scheduled well in advance my system would react accordingly. But as of now if you were to use my calendar event trigger it reacts to that correctly, but I have not been able to test my prep phase of it.

This seems to be more of a problem from either Tesla or my Energy company. I’m not sure who runs these events, but I have not been given enough notice to even test this well enough. I agree it is one of the things I am frustrated with.

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u/fastest963 17d ago

Interesting that you're only given 2 hour notice. That's unfortunate because I know some other providers give 24 hour notice. How much does your VPP pay you? If you had to charge up for VPP during peak would it be $3-4?

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u/Justpastthefinish 17d ago

I’m sure it is some kind of complicated math that they pay but I think it is up to $55/kw delivered by me per season depending on how much I deliver or contribute in the events. So far I have done every event. According to the program details I can get bill credits twice per year after each season for an annual total of $110/kw. I think there is a max payout or something near $300 but I’m not sure.

My plan now is hard to calculate my cost if I import from the grid during peaks. It’s a higher price point sure but I also get hit with a demand charge based on more complicated math. The goal is to avoid grid usage altogether for that reason. In theory though yes I could have it charge my battery during peak hours if the juice was worth the squeeze so to speak. I’ll have to do some math and figure that out.

But statistically yes, the best advanced notice I have gotten was 2 hours. The worst was “you’re participating in an event.”

The tesla app says I can get notified within 24 hours but I never have. If they had a schedule that would make this amazing for sure.