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Powerwall feature request: Expert Mode

Discussion in 'Tesla Energy' started by abasile, Apr 9, 2019.

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Would you use a Powerwall Expert mode if Tesla added it to the app?

  1. Yes! I want as much control as possible

    97.8%
  2. Maybe, but it might be too complicated for me to bother with

    0 vote(s)
    0.0%
  3. No, I'm basically happy with the existing options

    2.2%
  1. abasile

    abasile Conscientious investor

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    The Powerwall is a great product and I have high hopes for the future of battery storage at personal residences. Powerwalls can increase our consumption of solar energy, minimize our use of expensive peak power, and provide valuable backup services. For most people, the existing Backup-only, Self-powered, and Advanced modes should generally work okay without significant intervention - "set it and forget it".

    However, there is a significant minority of Powerwall users, including myself and a number of other regular TMC posters, who enjoy doing our best to optimize our use of the Powerwall. I'd love to see Tesla implement an Expert mode, aka. "Nerd Mode", for users like us. I've had two Powerwalls at my home for over a year, and I still make frequent use of the Tesla app to check on our solar generation, home consumption, use of the Powerwalls, and use of the grid, even when I'm away from home.

    Our electricity usage patterns at home are highly variable, so it seems somewhat futile for the Powerwalls to attempt to "learn" our patterns in order to control their charging and discharging. We are at home a great deal (I work from home), we have electric vehicles that occasionally need to be charged while peak electricity rates are in effect, we are in PlugShare and have EV visitors from time to time, and we appreciate being able to use our electric appliances at our convenience rather than on a set schedule. Further, as for our solar production, we're in an area where the weather can vary substantially over just a couple of miles' distance.

    Rather than depending on charge/discharge/standby decisions that are essentially hidden in a black box, I'd rather have as much manual control as possible, subject of course to physical limitations, the need to maintain the long term health of the batteries, and regulatory compliance demands.

    Specifically, a proposed Expert mode would allow us to set time of day and day of week ranges (going beyond Advanced mode), then configure a charge/discharge profile for each day/time range.

    For example, I would set the following day/time ranges:

    Range 1: Weekdays+weekends 12AM-8AM; weekdays+weekends 10PM-12AM
    Range 2: Weekdays 8AM-2PM
    Range 3: Weekends 8AM-10PM
    Range 4: Weekdays 2PM-10PM

    Then I would set the profiles for these day/time ranges as follows:

    Range 1 (equivalent to Off Peak):
    - Discharge on outages only
    - Charge using all solar up to reserve of 100%

    Range 2 (equivalent to weekday Part Peak):
    - Discharge on outages only
    - Charge using all solar up to reserve of 50%
    - Charge using excess solar above reserve of 50%

    Range 3 (equivalent to weekend Part Peak):
    - Discharge on outages only
    - Charge using all solar up to reserve of 30%
    - Charge using excess solar above reserve of 30%

    Range 4 (equivalent to Peak):
    - Discharge to cover all home usage, down to reserve of 30% (all solar exported)
    - Charge using all solar up to reserve of 30%

    I think this particular configuration would cover our current needs/desires quite well, though I would tweak the reserve percentages with the seasons. Obviously, charging and discharging would be limited to whatever the Powerwalls can appropriately handle. Overlapping ranges and gaps would not be allowed. Charging would always take place, when possible, during power outages. When charging from "excess solar", home usage gets priority on using available solar energy.

    Here are the options that I'd propose Tesla implement for each day/time range:

    1. Discharge options:
    A. Outages only
    B. To cover all home usage, down to specified reserve % (all solar is exported)
    C. To cover home usage in excess of available solar, down to specified reserve %
    D. Discharge to grid (where permitted), down to specified reserve %
    If (A) is chosen, then no other options apply. (B), (C), and (D) can be simultaneously selected, at different reserve levels.

    2. Charge options:
    A. All solar, up to specified reserve %
    B. Charge on excess solar when above reserve given in (A)
    C. From grid (where permitted), up to specified reserve %
    All of these options can be simultaneously chosen. If none are chosen, then charging takes place only if necessary to maintain the health of the batteries or in response to a Storm Watch activation.

    If there are conflicts between the discharge options and the charge options, then the discharge options would take precedence.

    I've attempted to keep this relatively simple, to increase the likelihood of an Expert mode actually getting implemented and used. Does this make sense? Am I missing anything?
     
  2. miimura

    miimura Well-Known Member

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    While we're dreaming, a "Demand Limit" and "Discharge Limit" option should be included in Expert Mode.
    I am defining Demand Limit as a value in kW where the Powerwall system will discharge to prevent the grid draw from exceeding that value.
    I am defining Discharge Limit as a value in kW where the Powerwall system will only discharge up to that power level. Any remaining demand will have to come from solar or grid.
     
    • Love x 1
  3. abasile

    abasile Conscientious investor

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    Is that to prevent the Powerwall from getting drained quickly if you do something like charge an EV during peak hours?
     
  4. miimura

    miimura Well-Known Member

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    Yes. You could also use it during overnight hours when Self-Powered to prevent the Powerwalls from doing excessive discharge while EV charging. For example, if your normal overnight usage doesn't exceed 1.5kW, you could set the Discharge Limit during the Off-Peak period to that value and most of the additional load for charging would come from the grid. If you wanted a portion to come from the Powerwalls, you could adjust the headroom up to allow that. For example, you don't want to exceed 5kWh from the Powerwalls while charging your car and you know it will take less than 5 hours to charge, you add 1kW headroom above normal household use to the Discharge Limit.
     
  5. cwied

    cwied Member

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    I'm wondering if multiple reserves might also address the EV charging use case. In theory one would be indifferent to when electricity is discharged as long as it's at the same rate level. Being able to set a higher reserve overnight that lowers when the part-peak rate period hits might address the situation more directly.
     
    • Like x 1
  6. JohnRatsey

    JohnRatsey Member

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    Charging from the grid using off-peak power needs at least two user defined settings:
    1. A maximum end of off-peak charge level so that the user can stop the battery from filling itself when a sunny day is expected following some cloudy days; and
    2. A minimum end of off-peak charge level so the user can encourage the battery to do some off-peak charging when a low solar generation day is expected following some sunny weather.

    My most recent correspondence from Tesla UK support in response to my complaints about inefficient off-peak charging behavour included the statement "That's why our Engineering Department is working on a feature for MyTesla App called "ability to send manual charge/discharge commands to the Powerwall". This will avoid the "strange" behavior that you have noticed in this situation and it will give you, as a customer, the possibility to better manage your battery."

    This suggests that Tesla might have realised that giving users more control will keep customers happier and would also save the company money in terms of the software development costs of trying to provide the optimum behaviour for innumerable different situations. However, I won't be holding my breath waiting for this to arrive (and there should be minimal need for off-peak charging during the summer half of the year).
     
  7. Shygar

    Shygar Member

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    How much of this can you do with the current API?
     
  8. JohnRatsey

    JohnRatsey Member

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    In my case I don't have the backup gateway which, I believe would enable control of the minimum charge. I can restrict the off-peak charging by shortening the off-peak period but Tesla support complained that frequently changing the off-peak period was impeding the battery's ability to learn and asked me to stop frequent adjustments.

    There's also the potential operating situation where the battery should go into standby during the off-peak period but not do any charging or go into standby after doing any charging. However, the software doesn't handle this properly at present as I see (i) the battery doing some off-peak charging followed by off-peak discharging (ie unnecessary round-tripping of power). These graphs shows the problem (off-peak is 01:00 to 07:00). 9th April was the last of several days of gloomy weather so off-peak charging started happening. Then today the sun shone. The off-peak discharging is very clear on the 9th April graph.
    PVOutput 09Apr19.JPG
    PVOutput 10Apr19.JPG
     
  9. abasile

    abasile Conscientious investor

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    I agree. As long as the applicable reserve is maintained, I'm not particularly concerned with how quickly the Powerwall discharges.

    For EV charging, I'd like it to be easier to avoid using the grid, but this would require integration between the Powerwall system and Tesla's vehicle products. Normally, if charging a Tesla vehicle during the peak rate period, I manually lower the charge current from the car's UI, typically to something in the range of 20-30 amps (at 240V) that can be fully supplied by our two Powerwalls while still leaving some room for home consumption. The tradeoff is that the car won't charge as quickly as it would if I left the charge current at the full 40 or 48 amps.

    For each configured day/time range (see first post), and assuming the necessary integration, I would propose the following EV charging options:
    A. Default behavior; no special EV treatment
    B. Charge from Powerwalls only, subject to reserve (useful during peak periods)
    C. Charge from excess solar only; priority over Powerwall charging is subject to reserve (useful to maximize self-consumption and reduce Powerwall charge/discharge cycles)
    D. Charge from either/both Powerwalls and excess solar as available (useful to maximize flexibility while maintaining self-consumption)
    E. Charge from grid, instead of waiting, if Powerwall reserves aren't met for (B), (C), or (D), or in the case of (C), if there's no solar production

    To achieve the necessary integration, perhaps Tesla's Wall Connector could communicate with a paired Powerwall system and dynamically adjust the available power for charging. No driver action would be needed. It would be up to the Powerwall owner (who may or may not be the driver) to configure how charging takes place. Also, it would be nice if the Energy Flow in the Tesla app had the option of breaking out EV charging from the rest of the home consumption. If in the future Tesla sells an electric heat pump HVAC system, this could be broken out as well. They'd have a whole home energy ecosystem!
     
  10. NuShrike

    NuShrike Member

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    Yes, I want the battery configuration options LG Chem and Sonnen already, for years, deployed into the production/field.
     
  11. KJD

    KJD Supporting Member

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    Has Tesla added any new features to the power wall since this thread was started ?
     
    • Funny x 1
  12. cwied

    cwied Member

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    Here are the release notes of what they released (note: doesn't appear to include Gateway 2 releases): Software Updates | Tesla
     
  13. sashton

    sashton Member

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    #13 sashton, Jul 18, 2019
    Last edited: Jul 18, 2019
    Features which are becoming more and more prevalent in the UK market which appear to be completely absent are:

    Support frequency response services - to work with aggregators e.g. EDF works with Powervault
    Support for Half Hour metering - i.e. If rate drops below x/kWh then charge.
    Charge to x% by a set time. ...rather than the almost completely useless algorithm that drives TOU

    Sadly the API or playing with the reserve really doesn't help with the top two.

    It's a shame as when I got my first PWII it had such potential but it has turned out to be the dumbest battery on the block.
     
  14. NuShrike

    NuShrike Member

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    I've been pointing this out since 2017 vs Sonnen/LG that this continues to be the dumbest battery on the block.

    Did you know Sonnen has a special plugs section on the battery so it can turn on/off loads depending on SoC and solar? Or remotely control those loads? Then there's random scheduling, not this one off-peak and one peak per week. There's a lot more if one scans their manuals, or older threads in here.

    You can do #2 via the API. TBC switching resolution is seconds of the day. The UI is only hour of the day.
     
    • Informative x 1
  15. sashton

    sashton Member

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    Well NuShrike you must have found a method which eludes me for #2

    I pull the half hour prices from the energy company easily enough - http://www.bowmill.net/xmenu/cost.shtml but getting the PW to standby and charge accurately within these variable 30 minute windows has me stumped.

    Yes, I understand the reservation can be set via api/1/powerwalls/*ID*/backup but applying the setting to the gateway and resetting it within the thirty minute window isn't achievable.
     
  16. NuShrike

    NuShrike Member

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    First is to "manually" send a custom TOU schedule via api/1/energy_sites/{site_id}/time_of_use_settings. I generally send it more than 30 minutes ahead of time and more than once (spaced at least 5 minutes apart).

    Then for reliability, use the local installer-api to make sure it actually switched over (to some mode of backup/self-consumption) at the time you chose. It's in the API thread.
     
    • Informative x 1

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