That is another reason I am considering installing a hybrid inverter and adding more solar. Since that system can be programmed to not feed the grid I only need to get a building permit. No interconnection agreement and I can incrementally add panels and batteries until I have enough capacity to only pay the minimum bill.
After finally getting down to within 1% of my set reserve last night, my Powerwalls got up to 80% today. I still haven't figured out why it doesn't charge them all the way when on TBC. It could've easily charged the Powerwalls to 100% and started exporting to the grid over 2 hours early...but no...my system started sending all of my solar production to the grid even though peak doesn't start for another 3 hours.Before 1.25.0 and 1.26.0, I think it used to charge the Powerwalls all the way, if possible, before peak started.
If they could just give me a setting to indicate what hours I want to self-power, I'd be happy!
No. My peak period is only 4 hours long, from 2 pm until 6 pm. During the entire peak period, I only use about 3 to 4 kWh so the Powerwalls have no problem covering peak.
For my TOU plan, I actually do not want to export any power to grid during peak because I don't have 1:1 net metering. The utility pays me less than half of what they charge for off-peak. I would like an option for not prioritizing export during peak. Self-powered is sort of working for me, but it doesn't support any time-based decision. e.g., for a certain cloudy day, I can see that just in self-powered mode it won't have enough to cover the whole peak (11a - 7p). Therefore, I would like to have an option of just charging it with all solar during part-peak (before peak). In the current self-powered mode, there is no concept of peak/part-peak/off-peak.
I had the Storm Watch activated for the first time last week. It seems that it was triggered by High Wind Warning in my area issued by National Weather Service.
No. My peak period is only 4 hours long, from 2 pm until 6 pm. During the entire peak period, I only use about 3 to 4 kWh so the Powerwalls have no problem covering peak.
One complaint with the Balanced TBC mode is that it often prioritizes sending production back to the grid when I want the Powerwalls charged more. Early last week, I was down to the 25% reserve and we had several cloudy days in a row. While I have Storm Watch enabled, it never activated and never tried charging up the Powerwalls and they hovered between 25% and 45% for days. Yes, the Powerwalls were charged up enough to cover the short 4 hour peak period every day but if the power had gone out due to the storm, they wouldn't have been able to cover an extended grid outage. I don't mind some efficiency losses if it means I can go days without grid power in an emergency vs. only a few hours.
Other times, it will still prioritize sending to the grid and needlessly drain the Powerwalls. For example, if I try to charge a car at noon to take advantage of the max solar power generation, I've seen it sending 12+ kW to the grid while simultaneously drawing 10+ kW from the Powerwalls. I could understand logic during peak period since it would be trying to generate the most peak credits while using power that was stored in cheaper periods...but it does this hours before peak is even scheduled to start! I usually have to switch it over to self-powered so that it will actually charge the cars and charge the Powerwalls. Most days, I can do both and still have hours before peak starts...but since 1.25.0, it doesn't seem to care when my peak period actually starts.
At this very minute, it is actually working as I would expect. I'm generating 10 kW and sending 9 kW directly to the house to cover the household usage and charge a car. The Powerwalls are also being charged at over 1.7 kW and a small amount is being drawn from the grid. Peak doesn't start for me for another 4 hours but I predict that within 1 to 2 hours, it will start sending the 12 kW to the grid while pulling 9 kW or more from the batteries.
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That's odd. I wonder why. If the PowerWalls are supplying your solar generated electricity to you all the way through the rest of the day and night and the next day until solar takes over again, maybe it's just because "it can" without giving up your self-generation solar use, and is offsetting some of the utility daytime fossil fuels as the use ramps up a tiny bit in the afternoon. Or maybe that's what it thinks it's doing. The purple "Net Demand" CAISO plot line just started upward about when you posted your post:It didn't happen as early as I expected today but when the Powerwalls were at about 70%, it switched over to send everything to the grid/house around 45 minutes before peak started. It's now showing that the Powerwalls are being drained, sending 200 W back to the grid and 700 W to the house. So not only is not charging up my Powerwalls all the way, but it's sending energy from the Powerwalls to the grid.
I look at it this way: Elon is not a full time Tesla CEO, so he doesn't micromanage the Energy division very well and they kind of are new to all this storage stuff, and are just learning how to optimize the charge and discharge timing and amounts, so they're getting their feet wet experimenting with their programming of our batteries. Once they learn enough, maybe they'll know what default programming to offer, and maybe they'll release its control more to us users. Since Elon likes to control what we do with our own equipment, I'm not holding out 100% certainty of that outcome. Either way, I hope Tesla learns more and more about optimal ways to program the batteries.
That's what I need and what I was expecting Tesla to have developed. Tesla's current implementation of Cost Saving is erratic. Today my PW drew 5.8 kWh of off-peak power to charge the battery and later on sent 2.3 kWh back to the grid as the battery was full. I get no money for what goes back to the grid.
It depends on where you live and if you have solar installed and how they program them.
It's not even consistent throughout the US. For my utility company in Colorado, our rates are something like 8 cents/kWh off-peak, 13 cents/kWh shoulder and 18 cents/kWh peak...but we only get 1.5 cents if we send power to the grid. We opted to take kWh credits instead to offset our usage since those are earned at the same rate that they would cost us.
I agree that lack of detailed data about the tariffs (peak / off-peak / feed-in - about 15p / 9p and 4p in my case) can't help with the decision making but it appears to me that ther control algorithms do not include forecast of the solar generation and this is currently the biggest short-coming. Consequently, tonight's off-peak charging appears to be based on what's happened during the past few days and doesn't allow for tomorrow's weather being different from today. This failing can be largely mitigated if Tesla provided the facility for a user-defined minimum charge level at the end of the off-peak period. The user can then adjust this based on past experience and the weather forecast.
