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Time-Based Control?

Discussion in 'Tesla Energy' started by powersaver, Feb 27, 2018.

  1. Dborn

    Dborn Confirmed

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    Does anyone have an email address for Powerwall support? I have the phone number, but I want to send some screenshots of my Powerwall performance. Basically I want to log my issue with discharge during off peak which continues.
     
  2. andrewrogers

    andrewrogers Member

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    @AnthonyB & @BJReplay great write-ups and graphs!

    I've also had the time-based controls for a little while and have been watching its behaviour. I'm seeing the same discharge behaviour starting in the early hours of the morning. There are also days when it uses power during off-peak or shoulder and then runs short in peak but for the most part, it's not doing too badly. Battery utilisation and optimisation against grid cost minimisation are definitely improved.

    My understanding is that the battery life is expected to be a function of the number cycles but also a function of time. Capacity will deteriorate over time even with very little cycling. Prior to enabling time-based control, I was generally able to have sufficient charge to get through to the start of evening off-peak with the reserve set at 70%, so only using 30% capacity. My theory on the early morning discharge is that they're optimising against this "use it or lose it" factor once some they have some confidence in the following days solar forecast. If the stated goal of the algorithm is "cost-saving" then this behaviour makes some sense.

    Interestingly I've not yet seen my battery charge overnight at all and have had it on cost-saving mode for a few weeks.

    @AnthonyB Retail tariffs have to factor in the network tariffs, for the Ausgrid network there's a more pronounced difference between Off-peak and Shoulder than appear to be reflected in your Powershops tariffs. Per some of the other posts a larger gap is more common I believe. My understanding is that the optimisation engine doesn't know or use exact price tariffs but rather weighting factors between off-peak, should and peak. I agree it could be improved and will be surprised if it isn't in future but have some sympathy for Tesla when trying to build a tool that can operate sensibly across a huge range of possible permutations and combinations of retail tariffs in Australia let alone other countries. At the same time, it needs to be a sufficiently simple user interface for the mass audience that is definitely less engaged than us!

    The time-based control interface to me is just this, typically Tesla, erring on the minimalist side, light on the detail but functional and very usable.

    It seems very likely that at some point the battery will also take into consideration peak wholesale price events and potentially peak network load assuming a mechanism exists to remunerate battery owners (e.g. Reposit / Diamond Energy). A dynamic control algorithm becomes a must to do this and I think it will inevitably be a little black box to the end users.

    It's definitely early days so am hopeful that there will be ongoing improvement in the efficiency of the control algorithm.
     
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  3. AnthonyB

    AnthonyB Member

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    Yeah, totally agree. And I'm certainly not wanting not expecting a lot more in the configuration. In my opinion, it should be a black box for the most part with all the smarts bring performed by the machine learning algorithms which will hopefully get much better over time. That said, machine learning still needs good inputs and that's where I think plugging in tariff rates makes sense to remove one big set of assumptions. It's got enough on its plate predicting consumption patterns and solar charge!
     
  4. AnthonyB

    AnthonyB Member

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    So after continuing to watch the behaviour of my system with T.B.C set to Cost-Saving, I've edited my "Price Schedule" configuration from reflecting my tariff (Off-peak, Shoulder, Peak) to only having Off-peak and Peak. I extended all of the weekday Off-peak periods into the shoulder and on Weekends turned on the "All Day Off-Peak" setting.

    As a catch-up on the reasoning behind this, the reason I'm doing this is that I'm seeing the battery discharging during Shoulder periods which is completely uneconomical for me based on my tariffs. Ideally, I only want the battery to discharge during Peak periods.

    While I appreciate that this is 'first release' stuff from Tesla, it is still frustrating that I have to 'game' the app to get what should be the expected behaviour is a not untypical configuration.
     
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  5. BJReplay

    BJReplay Member

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    I would hazard to suggest that the Tesla TBC (and this is from someone who doesn't yet have access) is unable to make the right decisions without tariff rate information (including feed in rate(s)).

    I can see why - because my TBC doesn't support shoulder because I don't have shoulder rates - only peak and off peak - and I haven't added it because it adds quite a lot of complexity to scheduling. You've simplified the decisions for the Tesla TBC to "charge in off-peak, discharge in peak" and told it there are only two periods and two rates to worry about. That's a lot simpler than 5 periods a day, and rules that depend on rates. But Tesla need to get to that level of complexity (or I'll have to, and I'm just one guy doing it for free).
     
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  6. Dborn

    Dborn Confirmed

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    I have found the email for Australian support. It is [email protected].
    I have sent them a few emails with screen shots. Yesterday I received a call from a support tech, with his direct email address. I have today sent him further requested screen shots. My hope is that now I have established communication, this will go to the programmers for tweaking/fixing.
     
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  7. andrewrogers

    andrewrogers Member

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    @AnthonyB Could this have the unintended consequence of the battery charging from the grid during periods it thinks are off-peak but which are shoulder on your tariff?

    Entirely agree there still more development needed on the algorithm.

    Predicting how much charge is needed as at the start of the peak period each day, requires predicting how much excess solar will be created that day, which depends on predicting load and generation that day. Some of these decisions have to be locked in by ~4-6am weekdays on the Ausgrid time of use tariff. To reliably cover peak period there's a trade-off between being conservative and often having excess capacity in the battery at the end of the peak period or sub-optimal charge/discharge outside of peak.

    Perhaps sub-optimal behaviour is unavoidable in some individual time periods in the course of achieving optimal use over the longer term.
     
  8. AnthonyB

    AnthonyB Member

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    I'll go with whichever one of you gets there first!

    My money is on you Bernard :)
     
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  9. AnthonyB

    AnthonyB Member

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    It absolutely could. I'll have to monitor closely and see what behaviour changes, for better or for worse!
    It'll all be publicly visible here (Anthony's Tesla Powerwall) and here (Anthonys House 6.930kW | Live Output) for those equally curious.

    Yes, but that is why we've (well, at least I've) paid the big bucks for a Tesla unit. That level of machine learning is part of their skill-set and what I expect them to do better than most other battery manufacturers. Of course, it'll never be perfect, but within a reasonable amount of time it should be able to cover 'the norm' as it learns:
    1. How much energy the Solar PV array produces and correlates that to meteorological data (i.e. learn the efficiency/inefficiency of my system in relation to more concrete data, i.e. how much sun was there).
    2. What are the normal patterns of energy consumption of my house, i.e. how much and when, weekends have higher consumption (due to no peak period), spikes at morning (breakfast) and evening (dinner), spikes when the pool cleaning system goes on every day at 5am, etc.

    My definition of sub-optimal behaviour is falling short of having enough battery to cover the peak period from time to time. Weather is quite unpredictable. Household power consumption, especially when heavily optimised, is more susceptible to less predictable spikes. For me, that is running my air-conditioner (~2000W) for a few hours, or running my oven (~2000W) for a few hours, or putting my pool pumps on high speed and also running the solar heating booster and the pool cleaner (~4000W).

    Discharging the battery in shoulder period which effectively costs me money? In my book that is just bad software configuration.and needs to be fixed as a high priority.
     
  10. AnthonyB

    AnthonyB Member

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    Thanks for sharing that. I guess I should drop them an email about the issues I'm seeing with TBC not handling ToU tariff systems that have a FIT less than Off-peak, and Shoulder quite similar to Off-Peak, and the resulting battery discharging behaviour during Shoulder.
     
  11. AnthonyB

    AnthonyB Member

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    actually, that was dumb as I'm getting grid charging during what is in reality shoulder period.

    I've changed it again so that the Peak periods are now extended to include the shoulder periods.
     
  12. AnthonyB

    AnthonyB Member

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    ...and now I'm getting discharging during "Peak" period that is really Shoulder period.

    "Gaming" the app to try and get optimal/desired behaviour jusy doesn't work.

    Looks like the only option is to give the feedback to Tesla and grin and bear it for now.
     
  13. cwied

    cwied Member

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    Does the time-based control still have the backup reserve setting? That would be one way to suppress discharging at the wrong time.
     
  14. miimura

    miimura Well-Known Member

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    Yes, it does. I don't see a screen shot in this thread of the Customize screen with it scrolled all the way to the bottom, so here's one that shows it.

    TBC Settings Page.jpg

    However, using the Reserve to prevent discharge is really brute force. It should be smart enough to avoid unwanted discharge. I only have a problem with when it charges on Cost Saving. I never had a problem with when it discharged. Balanced has been working well for me.
     
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  15. Frankman60

    Frankman60 Member

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    Thanks miimura. After reading through your posts in this thread I will begin with the “Balanced” setting because it seems to perform the way I would like it to perform.
     
  16. miimura

    miimura Well-Known Member

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    I have noticed recently that the Powerwalls are not just doing hard transitions any more in TBC Balanced mode. When the Peak Period starts and ends it does to hard mode changes to start discharging to match the house and then stopping at the end of Peak, but the transitions for charging are more tapered now. See chart below. The transition from charging with All Solar to charging with Surplus Solar took about 30 minutes to taper. Previously the chart had step changes in grid load.

    2018-04-26_14-40-48_000.jpg
     
  17. Frankman60

    Frankman60 Member

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    Are you saying that the tapering is a changed recent behavior in the balanced mode? Is the tapered behavior the same In the cost saving mode?

     
  18. miimura

    miimura Well-Known Member

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    The tapering is new to me in Balanced mode. Today (Thursday) is the first time I've noticed it, and I look at the charts A LOT. However, it only tapered the charging, not the discharging. Since our consumption was very light this evening it kept discharging through the evening Part-Peak (9-11pm) and then abruptly went into standby at 11:00 for the start of the Off-Peak period.

    I have not gone back to try Cost Saving mode since Balanced was more to my liking. Eventually I might go back to Cost Saving to see if it still does the things that I don't like, but probably not for quite a while.

    BTW, I'm still on PW Version 1.15.1
     
  19. SD Diver

    SD Diver Member

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    What determines the availability of this functionality? My firmware fist went from 1.15.3 to 1.15.5 and I’ve yet to receive it.
     
  20. abasile

    abasile Conscientious investor

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    Tesla told me a few weeks ago that they're rolling out the TBC functionality to customers in stages, and that everyone should have TBC by April-end (!). I don't know how they've determined who is in what stage. We are still waiting. For now, I'm still using the app each evening to put our Powerwalls in Backup mode during SCE's nighttime Super Off Peak period, when we charge our two EVs, and I'm switching back to Self Consumption mode each morning. With TBC, I'm looking forward to having the ability to export all of our Peak solar generation, not just our solar surplus.
     
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