Question on Time Based Controls - Balanced

[eml2]

@miimura I also notice my PW whipsawing back and forth whenever there is solar generation, regardless of shoulder or peak period. This whipsawing only happens in TBC-Balanced. It doesn't happen in Self-Powered and I never try TBC-Cost Saving.

When I check web UI to see exactly what happen during the whipsawing, this is what I notice:

1. At the top of the hour (00:00), it works exactly as self-powered. Grid is closed to 0, with PW either in charging or discharging depends on generation and load.
2. After 3 minutes later (00:03), PW goes to standby. Grid is either import or export, depending on solar and load.
3. After another minute (00:04), PW will come back online to either charge or discharge, depending on solar and load. However, grid will not maintain closed to 0. Instead, depends on how much energy is exported or import when PW goes to standby (@ 00:03), it will try to neglect it for the duration till 00:15.
4. At 00:15, the cycle repeats.

Just wonder if anyone also seeing this behavior.

 

[miimura]

Mine has only done those strange things in the shoulder period when the SOC is high, usually on a Monday morning. Since the starting SOC was only 45% this morning, everything ran very smoothly. It charged from All Solar until 10:45, then charged with Surplus Solar, then started discharging at 1:45, 15 minutes before the Peak period started. The SOC was 88% when it started discharging. I think next time I will just raise the Reserve on Sunday evening. This weekend may be cloudy with some rain, so I may not have to intervene.

 

[JES2]

Do you use Balanced or Cost Savings settings? My understanding is if you use either of these two profiles, and only configure Peak and Off Peak (no shoulder) periods, the PWs will only discharge during the defined Peak period. Is that what you have experienced? I’m assuming that you are going to change the setup on June 1st when the Summer season begins.

This is not true (at least me.) The Powerwalls continue to discharge at some point during the off-peak when Tesla "decides" they have a sufficient amount of reserve. I can counteract that by raising my reserve levels up before my off-peak begins. Once peak begins, then I can reduce my reserve, especially for cloudy days.

However, it used to be that the changing of reserve would take only 10 minutes to initiate. This morning, it took an hour. I believe that the Tesla Energy folks put a fix on my system that requires the entire hour. (I assume it was them, since I noticed I had to log in to my account this morning. That seems to happen whenever they go fooling around into my system.)

I run in cost-savings mode, with a peak (6 am to 8 pm) and an off-peak (8 pm to 6 am.) I pay $0.00 during off-peak and $0.23 during peak. Two PW2s with a 8.33 kw solar system from Solar City. I am on version 1.34.3.

 

[tambam]

I've been using TBC-Cost Saving for the last two weeks (PW installed two weeks ago, enabled TBC two days later). Today it decided to charge to only 70% SOC during shoulder and ran out of charge before peak was over (reserve was set to 25%), causing me to pull from the grid during peak (ugh).

Household use was a little higher than usual. Is this just the PW not having enough historical data to make better decisions? If I mess with reserve (set to 50% during shoulder, 25% during peak) will it mess with the learning?

 

[miimura]

I've been using TBC-Cost Saving for the last two weeks (PW installed two weeks ago, enabled TBC two days later). Today it decided to charge to only 70% SOC during shoulder and ran out of charge before peak was over (reserve was set to 25%), causing me to pull from the grid during peak (ugh).

Household use was a little higher than usual. Is this just the PW not having enough historical data to make better decisions? If I mess with reserve (set to 50% during shoulder, 25% during peak) will it mess with the learning?

Annoying, isn't it? You just missed out on a little arbitrage there because you sold a bunch of solar at Part-Peak when you could have used that energy to avoid Peak usage. I would prefer that it err on the side of having spare energy in the batteries.

Powerwall Support will tell you that changing the settings frequently will mess with the learning.

 

[power.saver]

Ditch your part-peak (shoulder) and run only off-peak and peak so that won't happen.

 

[SoundDaTrumpet]

Ditch your part-peak (shoulder) and run only off-peak and peak so that won't happen.

I do the same like @power.saver. New PW user here like @tambam. Maximized rate arbitrage here. I would prefer to play nice with the grid, charge PW mid-day, and avoid exporting mid-day when I perceive the grid doesn't want my excess.

 

[Takayama Todd]

I have been following the thread with interest. I currently have my panel/powerwall set in Balanced mode, with a 50% reserve, and version 1.44.3. My PGE rates for a 24 hour cycle are:
Off Peak: 12am-3pm
Shoulder (partial peak): 3-4pm
Peak: 4-9pm
Shoulder:9-12pm
Up to 48 hours ago. I was fine with my settings until yesterday my powerwall started discharging at 7:30am with a 61% battery capacity remaining. I called the Tesla help line and spoke to their Tesla powerwall technician. She and I were looking at the same powerwall behavior==discharging during off-peak.
Technician response 1:She started to inform me that was normal for the battery and that if we look at previous days you can see the same behavior----My response, No all previous days there was never discharging during off peak hours at 7:30am.
Technician response 2: Since your solar input is so low at 7:30am e.g. 0.2 kWh and your electrical need for home is 0.4 kWh, then your battery will discharge; My response, No my battery has never dischaged at 7:30am, is there a software problem?
Technician response 3: Its normal for your power wall to discharge to get down to reserve set level: No way, as we were discussing, the powerwall capacity dipped down to 60%, when it reversed and started recharging at 9am while on the phone. My response; Did you see that change in discharge to charge--I think there is a flaw with the software program?

After consulting with a Senior Technician, she decided to open a case and monitor the situation to see if this cycle repeats it self. It has been 48 hours and the cycle has repeated itself over the last 48 hours---e.g. discharging from 7:30-9am. Currently on the second day. It is 9:05am and my powerwall capacity is discharged to 61% and is displaying "hacksaw" behavior of discharging/charging to meet the need of the home at only 0.3kWh. Solar input to house is 0.2 kWh. No real sign of permanent charging during off-peak.

I hope the Tesla programmers are getting a good hard look at this software version and decide to make updates!. I am tempted to switch to Cost Savings mode but will wait to see how this plays out....

 

[JayClark]

I have been following the thread with interest. I currently have my panel/powerwall set in Balanced mode, with a 50% reserve, and version 1.44.3. My PGE rates for a 24 hour cycle are:
Off Peak: 12am-3pm
Shoulder (partial peak): 3-4pm
Peak: 4-9pm
Shoulder:9-12pm
Up to 48 hours ago. I was fine with my settings until yesterday my powerwall started discharging at 7:30am with a 61% battery capacity remaining. I called the Tesla help line and spoke to their Tesla powerwall technician. She and I were looking at the same powerwall behavior==discharging during off-peak.
Technician response 1:She started to inform me that was normal for the battery and that if we look at previous days you can see the same behavior----My response, No all previous days there was never discharging during off peak hours at 7:30am.
Technician response 2: Since your solar input is so low at 7:30am e.g. 0.2 kWh and your electrical need for home is 0.4 kWh, then your battery will discharge; My response, No my battery has never dischaged at 7:30am, is there a software problem?
Technician response 3: Its normal for your power wall to discharge to get down to reserve set level: No way, as we were discussing, the powerwall capacity dipped down to 60%, when it reversed and started recharging at 9am while on the phone. My response; Did you see that change in discharge to charge--I think there is a flaw with the software program?

After consulting with a Senior Technician, she decided to open a case and monitor the situation to see if this cycle repeats it self. It has been 48 hours and the cycle has repeated itself over the last 48 hours---e.g. discharging from 7:30-9am. Currently on the second day. It is 9:05am and my powerwall capacity is discharged to 61% and is displaying "hacksaw" behavior of discharging/charging to meet the need of the home at only 0.3kWh. Solar input to house is 0.2 kWh. No real sign of permanent charging during off-peak.

I hope the Tesla programmers are getting a good hard look at this software version and decide to make updates!. I am tempted to switch to Cost Savings mode but will wait to see how this plays out....

I have had "balanced" mode discharge during off-peak, which frustrated me also, but it was common. For my system this has been the case going back many software versions.

The description for "balanced" strategy when you click "Learn more" in the app says, "Powerwall will discharge during all periods, minimizing exports during shoulder and off-peak", but clearly says it will discharge during all periods. That leads me to believe the programmers will think it's working as they expect. I actually would have expected support to quote you that information, but service and support "knowledge" is a Tesla weakness IMHO.

My impression is the "algorithm" the programmers are using is making a prediction based on usage and recent solar production for the whole day, taking into account previous days usage/production, also based on PW SOC, and somehow automagically then predicting (right or wrong, and seemingly "all of the sudden" after having not done so before) that it can now discharge "more", possibly even during off-peak periods if it is predicting it can otherwise can cover all loads during Shoulder & Peak, in addition to some off-peak usage.

So in my case, I still use Balanced, but I also combine that with 3rd party software to automatically schedule and raise the reserve during off-peak and then lower it back to my target after my off-peak window, which seems to insure it doesn't discharge during off-peak. I wish this was built into the Tesla app.

PS: The 3rd party software I use is @Darwin "Power Wall Manager" application for Smartthings, and there are other ways to do this if you're comfortable with a little scripting and setting up a service on a server of kind.

 

[Takayama Todd]

I am willing to ride TBC-Balanced Mode out despite some annoyances and positive benefits e.g. discharging during off-peak, a benefit I like is that is doesn't discharge during the entire period of part-peak from 3pm-4pm. The powerwall will start discharging around 3:40pm.
I recently switched from rate plan TOU-A (Peak/Off-Peak M-F, Off-Peak on Weekends) and had set TBC advanced setting to Cost-Savings. I found my yearly true-up was a unfavorable or -($). The good aspect was the powerwall never discharged during off-peak, BUT there wasn't enough differential in savings with TOU-A to make it worth while with a panel/powerwall combination for either summer/winter rates. So I am stuck with the central dogma of EV2-A rate: Balanced Mode vs Cost Savings Mode?

 

[miimura]

I was just switched to EV2-A this Winter. In the past, on EV-A, Cost Saving Mode did not work well for me because I didn't have any Off-Peak generation during the week. In many circumstances, the Powerwalls didn't want to charge during Part-Peak, so I didn't have enough battery to make it through the Peak period on Battery. That's why I have been on Balanced Mode for the 1.5+ years since the feature was released.

My seasonal daily solar generation is just starting to approach my daily Peak usage, so there's not much for the algorithm to screw up. When I have more generation in the Spring and Summer, there's more flexibility for it to do weird stuff. Hopefully, it will gradually use the extra energy to power the house through the Part-Peak too. If not, I will just extend the peak hours in the app. It will probably also help that EV2-A has the same schedule 7 days a week. Balanced used to discharge extra during the Friday evening Part-Peak period because the weekend was the only time that I had Off-Peak generation. It was better to offset the Part-Peak usage when the battery energy could be replaced with Off-Peak solar.

 

[Takayama Todd]

The defined behavior for TBC-Balanced Mode at version 1.44.3 (reserve set at 50%) is: the powerwall will charge from excess solar during off-peak and shoulder (if required). Powerwall will discharge during all periods, minimizing exports during shoulder and off-peak . It appears my new normal powerwall behavior for the past 3-days is discharge from ~7:30am to 9am (off-peak), then flips into recharge mode. The discharge during off-peak occurred at 66% powerwall capacity. At least for the past 3-days, the behavior of the powerwall doesn't support the what the Tesla Technician said about powerwall discharging to your set reserve level. (see Technician Response 3, from post 48). Note, for the past 3-days, the powerwall has charged to 100% except for Tuesday where it only charge to 87% and performed arbitrage and sold solar back to PGE. What was implied earlier by JayClark with algorithm and prediction, is what I am naming as "automagically" I am starting to believe.

 

[Takayama Todd]

I am at TBC-Balanced Mode set at 50% reserve with app version 1.44.3 and discharging during off-peak. It has been 3-days with consistent powerwall behavior of discharging from ~7:30am-9am during off-peak hours. Today, the powerwall discharged to 67% before flipping to recharge around 8:45am. I believe I have seen enough that contradicts the Tesla technician Response 3 (post #48) where they stated that it's normal for your power wall to discharge to get down to reserve set level. This may be a true statement in a different context, but not here.
To note, i have been charging to 100% except for yesterday where I charged to 87% capacity, then sold the rest back to PGE by arbitrage.
I agree, that Tesla uses algorithms, forecasting and some AI(?) for learning customer use patterns, but I am beginning to call it 'automagically" since there doesn't seem to be any strict algorithm other than successive powerwall discharging in the morning.

 

[Takayama Todd]

One final observation has been around TBC-Cost Savings which I had been part of in CY2019. The goal of the program is, "To maximize savings. Your Self-Powered score may be lower." I aggregated my Jul-Dec 2019 self-power % score and came up with an avg monthly value of 28.7% and median of value of 29%. The firmware version from that period range was 1.37-1.43. These results make sense since the programming for powerwall was focus toward cost vs. self-powered footprint. My CY2019 settings of TOU-A / TBC-Cost Savings didn't provide enough financial savings at the yearly true-up---was unfavorable for me ($).

My early/preliminary results for February at EV2-A / TBC-Balanced Mode for self-powered score is an average of 46%. I realize this is not the same time frame, but I am getting a better understanding of TBC-Balance Mode. I am hoping my current plan and settings provides a favorable yearly true-up ($) at years end. Note: My projected PGE spending is $24 dollars less for February than the same time last year.

My working theory with a solar panel/powerwall combination, that choosing the right rate plan e.g. EV2-A has more to do with overall savings ($) than the TBC advanced settings of cost savings mode or balance mode.

 

[Takayama Todd]

An update with my powerwall/panel settings. My settings are at EV2-A / TBC-Balanced with reserve of 40-50% for winter rates. The month of April had nice weather with one-day of household HVAC. I had a net -$2.26 dollars sold back to PG&E and that was a first time ever with my system. The performance measures have been 65-75% for self-powered I realized the TBC-Balanced setting is driven by the reserve setting and uses the powerwall based upon reserve availability. For me, the AI PG&E brain uses the powerwall as early as 1-2 AM in the morning at a low reserve setting and at 4-5 AM at a higher reserve setting e.g. 45-50%. Summer rates begin June 1 and I plan to drop my reserve down to 25-35% in order to account for the electrical drain via the HVAC.