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New Powerwall Advanced Options [Toggles for charging from and discharging to grid from powerwalls]
- Thread starter dailo
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Merged posts into the thread with the most current discussion on the topic.
I'm happy to see "Export Everything" appear over the last few weeks, but I'm struggling to see how I can optimize its usage.
I'm in PG&E EV2A land. 25c/KwH off-peak and over double that during peak in the summer. Is there a more cost-effective strategy than manually turning on "Export Everything" every day at 4pm and turning off when I reach a capacity I think will see me through until midnight (roughly 1 hour based on my current export graph). Or script it?
I'm in PG&E EV2A land. 25c/KwH off-peak and over double that during peak in the summer. Is there a more cost-effective strategy than manually turning on "Export Everything" every day at 4pm and turning off when I reach a capacity I think will see me through until midnight (roughly 1 hour based on my current export graph). Or script it?
It's not financially optimal to consume until midnight. I just let my Powerwalls discharge during peak and use the grid for the rest of the day. If you're on NEM 2.0, you can set the price for export slightly lower than the price for import so you don't accrue non-bypassable charges from consuming peak energy. The algorithm tries to make sure you don't import anything during peak if the price for export is lower than the price for import.
The reason why this is more cost effective is that you're only saving $.45/kWh if you discharge during the shoulder period (9pm-midnight). The discharge during peak gets you $.55/kWh.
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NEM1 or NEM2?
If NEM1, the question is just whether you currently are ending your Peak period with the PW at the Reserve setting. If you are, Export Everything doesn't help you, as there is nothing left to export (and you could consider lowering your Reserve to save money). If you aren't, Export Everything will let you Export more at Peak and less at Off Peak, so that's a financial benefit, if you are currently a $ consumer at true-up.
If you're NEM2, the same basic idea applies, but see the previous post for the additional wrinkles.
Cheers, Wayne
It is confusing!
Under the old system we could only export solar. It was cool never importing expensive juice. Essentially, it let us time shift our consumption: starting with 100% charge when partial and peak periods began, PW would discharge to cover our more expensive consumption. Then, the next morning, solar would recharge to 100%. Our peak evening consumption was time shifted till the next morning when solar would cover it.
In my case (also on PG&E EV2-A), my 3pm to midnight consumption would typically use about 50% of PW capacity. All of my grid draw was off peak, and some of my export was partial and peak. I really loved the solar export during peak & partial peak, with zero grid after that.
Ah, but now I can also export from 50% down to 20%, 30% more, during peak! I describe it as time shifting solar production, as well as consumption. But this does mean you have to import during the evening 9 to 12 partial peak period. As wwhitney pointed out, that is OK because you sold that energy at peak price and are now buying it back for less at partial peak. Still making money on it.
In my case, in the summer, starting at 20%, I reach 100% during off peak, then start exporting. In the old days, I discharged only to 50% to run the house and thet extra 30% would export at off peak. So, in effect, it is costing me off peak price for the extra 30% which I now discharge at full peak price.
What my PW does is fill up in the morning, and then start to discharge when peak starts at 4. It lets solar go out, but as than ramps down, the PW discharge ramps up, keeping the grid export rate at 3.5 kW. This was the max export rating of my solar, so PW figures it is ok to dump that fast. But as 9pm approaches, PW slows down discharge to ensure that it won't hit my 20% reserve until 9. (Even though I am on NEM1, I set my sell prices 3¢ below buy to observe it's NEM2 behavior.). At 9 it is down to reserve, so the house starts to draw from the grid.
It did appear that PW took a few days to be learn my evening consumption, and that does vary day to day. So now it ramps down the discharge earlier and then up again as needed to get down 20% at 9pm. No script needed.
So, as far as I can tell, just setting it to export everything is optimum, at least during summer when I can reach 100% charge before 3. On a couple of cloudy days, I have engaged grid charging in the morning. but that is a whole other discussion. (Some of us have grid charging constrained by Tesla, some by PG&E, some by IRS. Hence another discussion, that.)
Too long, sorry. But it is complicated, and quite a mind shift from before. Finding simple ways to conceptualize it takes time. I am still trying to calculate what my true-up will be with this new feature, plus charging an EV plus adding more solar, plus possibly switching to NEM2. My wife considers herself an Excel / Tesla widow. ;-)
SW
aesculus
Still Trying to Figure This All Out
Thanks for updating your status. I am getting closer to turning this on and letting it learn. It sounds like for the first few days I might have to give it a pseudo reserve higher than I want and then manually turn it off while it's in "learn mode". Then set my reserve to the correct level and hopefully it will stop discharging just at the end of peak. My export rate is 10 kW, so it makes a huge difference. I wonder if I should turn on export everything at the time it would be if it discharged at the high rate and ended at reserve at end of peak. That way I lessen my risk and don't have to mico manage it.
I did set my sell prices 3 cents lower too and even on non export I think I have seen a small behavior change. It seems a little less anxious to dump power during partial peak on a Friday.
Seems like if you want to let it learn, you shouldn't mess with the settings while it's learning. Just set the settings for what should give the optimal behavior if it's clever, and give it a week to show you whether it can be clever. Accept that during that week the behavior will be suboptimal.
Cheers, Wayne
aesculus
Still Trying to Figure This All Out
But I don't want it to drain my batteries and then pay for grid energy during peak. That is what it was doing before.
I may have to incrementally "educate" it, where I move the bar 10% each day or something.
aesculus
Still Trying to Figure This All Out
Rapid test revealed that at 7PM I turned on Export Everything and it started pumping back power at 10 kw until around 7:30 when it got within 5% of my reserve. It they started scaling back the export value varying between 2.5 kW and 0 to get me to my reserve of 50% at my 9PM peak period ending.
So I think it has learned enough for it to graduate to a more significant test tomorrow where I let it run to a reserve of 30% and turn it on at 5PM.
Hi all I apologize if this has been answered before - I am with PG&E and had my Powerwall's installed through SGIP. According to Tesla support, they are unable to activate grid charging due to my Powerwall's being installed by a third party (Swell Energy). Has anyone else run into this? I originally called Swell Energy who pointed me to PG&E, who in turn pointed me to Telsa. Any help would be appreciated.
aesculus
Still Trying to Figure This All Out
Just a short observation on my Export Everything test. The PWs drained slowly to my reserve (50%) at the end of peak which is great. This AM they were at 49% which is acceptable from the 10 hour time difference and temp difference.
So I thought I would try to be more aggressive today and put the reserve at 30% and see how it would perform during peak, giving it more room to discharge at those high rates. I was shocked to discover they immediately started discharging at partial peak. Why in the world would they do that when the peak costs are 2x the partial peak costs?
So I moved it to 40% and it stopped discharging but then sent the solar power to the home and grid. See picture. Again why? I would be much better off banking that energy to be sold back later during peak.
So I have them back to 50% reserve again and will toggle the reserve when in peak mode this afternoon.
So I thought I would try to be more aggressive today and put the reserve at 30% and see how it would perform during peak, giving it more room to discharge at those high rates. I was shocked to discover they immediately started discharging at partial peak. Why in the world would they do that when the peak costs are 2x the partial peak costs?
So I moved it to 40% and it stopped discharging but then sent the solar power to the home and grid. See picture. Again why? I would be much better off banking that energy to be sold back later during peak.
So I have them back to 50% reserve again and will toggle the reserve when in peak mode this afternoon.
Because by changing the settings all the time, you are never giving the algorithm a chance to settle down. Maybe it's programmed to throw out all the historical data whenever you change the settings, who knows? Just set it to whatever should give you the correct behavior, and don't make changes for 3-7 days. Give it a chance to figure things out. Accept it will do it wrong for a couple days.
Cheers, Wayne
I'll add to this that even in simple cases that shouldn't need learning, changes to settings in the app may not take effect instantaneously. For instance, when I lower the reserve level during peak, it seems like the new level only takes effect roughly on the quarter hour. A change at 5:29 will take effect within a couple of minutes, whereas a change at 5:30 won't take affect for at least 15 minutes.
Additionally, when changing modes I've seen occasional transient behavior that seems contradictory to the mode (e.g., charging during peak when on TBC).
I currently have automation running that switches between export everything and export solar only and this seems to take effect right away.
aesculus
Still Trying to Figure This All Out
Mine has been this way for awhile.
Note that it can even export higher than 10 kW if it combines current solar and the max PW export. I have seen it at 13 kW before. My PTO states 10 KW so ...
Code:
max_site_meter_power_kW: 1000000000,
min_site_meter_power_kW: -1000000000,Note that it can even export higher than 10 kW if it combines current solar and the max PW export. I have seen it at 13 kW before. My PTO states 10 KW so ...
SoundDaTrumpet
Member
All my exports went from 3.9 kW (inverter size) to 9.5~9.7 kW (max discharge for 2PWs) ever since Monday, 6/18/22. (Initially suspected that Tesla tweak my discharge cap after inquiring about the Tesla Virtual Power Plant. Looks not to be the case.) In response, I have moved my peak later to 7:30pm-9pm, so I hit the 20% reserve closer to bedtime. I fear this places greater stress on the batteries. Maybe this small discharge window is causing the PWs to learn poor habits, and should change settings to a 2-9pm peak (EV-A) instead. Thoughts?
jhn_
Member
Mine is this way too. Not sure if it was that way since install or since joining the VPP.
aesculus
Still Trying to Figure This All Out
Mine behaved this way initially but over a few days they seemed to figure out how not to drain themselves before peak was over. They still discharge at a high rate but then stop quite a while before peak ends and then "cruise" into partial peak by just running the house load. My reserve in this example is set to 50%.