Time-Based Control?

[lance.cazeault]

I received the call from a TESLA rep on Friday afternoon on what they finally found.

I was told that they found a bug in how you need to edit the times for the weekend. For whatever the reason is, if you enter the weekday schedule and weekend schedule at the same time, it will act all screwy.

From what the rep advised me to do, enter your weekday schedule, save and exit the app (exiting may not be absolutely required here, but better to do more than less)
Then go back into the system, and make the changes to the weekend time schedule, save and exit the app. (exiting is required this time)

Once I followed those procedures, this past weekend the system worked as I expected it to work, I will continue to monitor and advise if there are further issues.

 

[arnolddeleon]

My Powerwalls were upgraded to 1.17.2 sometime today It also looks like Tesla was playing with my reserve settings. This is probably in attempts to troubleshoot the bug where it continues to discharge even when it is at/below the reserve level. Early returns are promising, I'm not seeing it discharging.. I'm looking forward to the next few days to see if my system will finally be where I expected it to be 6 months ago.

 

[lance.cazeault]

@arnolddeleon I'm also on the 1.17.2 firmware for the Powerwall. They pushed that update to me on 02JUN -- still took them about 3 weeks to figure out what the cause of my issue was.
Quick question, how are you seeing that they have been playing with your reserve settings? (Mostly curiosity on my part if they were doing that to mine when they were troubleshooting the issues).

 

[arnolddeleon]

@arnolddeleon
Quick question, how are you seeing that they have been playing with your reserve settings? (Mostly curiosity on my part if they were doing that to mine when they were troubleshooting the issues).

The setting is different from what I set it to. Unless my phone is doing phantom changes, I'm assuming it is them.

 

[arnolddeleon]

I also discovered this morning that my system was switched to self consumption mode yesterday. I don't know if that was intentional or side effect of the upgrade.
I switched it back to TBC and today/night has looked good so far. I also lowered back down to where I think I want it. Feeling quite optimistic.

 

[arnolddeleon]

This is the kind of day that Powerwall typically expects for me:

It basically took all my off peak production and dumped into partial peak and peak. On this day it was correct in starting to discharge during the early part peak, it actually could have started earlier because it didn't hit the reserve limit before off peak started again.

The next image is what happens when there is air conditioning load, the Powerwall starts even earlier than the day before (probably trying to correct for the minor miss the day before), it runs out of energy before the peak period is over.



As I said in earlier post, I think this is a real hard problem to solve, it's trying to forecast the future for small system where the decisions I make can make a huge difference. At this point I'm quite satisfied, even impressed with what Tesla is doing.

 

[miimura]

I used to be really annoyed when it would run down to the Reserve before the end of the Peak period, but in actuality it's not that big of a deal because it's already earned you so many solar credits exporting "all solar" during Peak that using a little is not the end of the world. However, Balanced would have waited until the Peak to start discharging and would have made it all the way through the Peak period.

This was my Friday on TBC Balanced. It always continues to discharge until the end of Part-Peak at 11pm on Friday nights because there is less valuable Off-Peak generation on Saturday to replace that energy.

 

[arnolddeleon]

TBC has been working well, it's kinda boring now. Today being a holiday reminded me that Tesla doesn't appear to support alternate schedules (e.g. summer vs winter and/or holidays). Does anyone know what Tesla is planning to do?

 

[ohmman]

TBC has been working well, it's kinda boring now. Today being a holiday reminded me that Tesla doesn't appear to support alternate schedules (e.g. summer vs winter and/or holidays). Does anyone know what Tesla is planning to do?

I’d asked about this in the thread earlier. Might be tough to hardcode all the different providers, regions, and rate plans that have different holiday treatment. Though, a checkbox that says “treat US holidays as weekends” might be a simple implementation.

I just manually change my weekday schedule on holidays and it works OK.

 

[MorrisonHiker]

I’d asked about this in the thread earlier. Might be tough to hardcode all the different providers, regions, and rate plans that have different holiday treatment. Though, a checkbox that says “treat US holidays as weekends” might be a simple implementation.

I just manually change my weekday schedule on holidays and it works OK.

The problem with that is which "holidays" are considered holidays?

Wikipedia says "As of 2012, there were eleven federal holidays in the United States,..."

My energy provider only has six holidays on their TOU plan:

What are the six observed holidays that are considered off-peak?
New Year’s Day, Memorial Day, Independence Day, Labor Day, Thanksgiving Day, and Christmas Day.

I guess if they just added "major" to your suggestion, it could work if they treated major US holidays as weekends.

 

[ohmman]

The problem with that is which "holidays" are considered holidays?

Wikipedia says "As of 2012, there were eleven federal holidays in the United States, ten annual holidays and one quadrennial holiday (Inauguration Day)."

My energy provider only has six holidays on their TOU plan:

Good point. Probably best to just ignore them and miss a few days a year of perfection.

 

[arnolddeleon]

Good point. Probably best to just ignore them and miss a few days a year of perfection.

Yeah, it's pretty good now. OTOH if they have the logic for weekend vs weekday it isn't a long leap to add calendars for holidays. The other option is to give us one touch "today is a weekend". The main pain for is UI for setting the periods is freaking horrible. Trying to adjust those damn sliders is a pain to get exactly right.

 

[cwied]

One wrinkle: on the PG&E E6 rate, holidays are not the same as weekends. Instead, they're off-peak all day. I just switched to backup-only yesterday.

 

[Artimis]

@Artimis - the key to OhmConnect is that it's a targeted demand-reduction program. If you already reduce your demand on all days by using self-consumption mode, then you won't have any demand to reduce on the target days. Therefore, if you set your OhmHours to 5pm-7pm, you should have the Powerwalls on standby (or charging) during those hours if you want to participate in OhmConnect. If you don't want the risk of cloudy days, you can set your OhmHours later in the day to avoid solar production fluctuations. I have my OhmHours set from 7pm-9pm and that's why I've set those hours to off-peak in my schedule.

Out of curiosity, what is your motivation to run on self-consumption mode? Given the round-trip efficiency losses, don't you end up paying for more electricity than if you were to just use net metering?

Sorry, I missed your message before. Yes, I understand how this works for OhmConnect. What I was saying is that between 5-7pm, I'm already using all the electricity my solar panels are providing (for cooking or the AC, etc). So as far as the grid is concerned, I'm usually consuming 0Kwh or dumping in very little. I put the Powerwalls into Advanced - Cost Savings mode for Ohm hours during this time so that my house is powered by the batteries and 100% of my solar produced goes into the grid. This technique earned me 580 points on the last Ohm hour (with no bonuses/multipliers) so it seems to be working ok.


As far as why I mostly operate out of self-consumption mode, I am required to discharge my powerwalls as part of the SGIP incentive anyway. Yes, there may be some round-trip efficiency losses, but the fact I am also not hit with any non-bypassable charges for grid use ends up negating that cost-wise.

 

[dotbombjoe]

FWIW, I'm still not getting great results with TBC set to cost saving mode. It often discharges too early during the shoulder and then hits the threshold during peak. I know there is some variability there (ie, weather, how much demand I place...) but I'd expect it to do better. I mean, I don't really care that much about where my threshold is set but no matter where I set it, it doesn't seem to reliably ensure peak can always be covered.

I've been adjusting the threshold before and after peak time to try to manually manage it...but maybe I should try to go back to balanced instead?

 

[AnthonyB]

FWIW, I'm still not getting great results with TBC set to cost saving mode. It often discharges too early during the shoulder and then hits the threshold during peak. I know there is some variability there (ie, weather, how much demand I place...) but I'd expect it to do better. I mean, I don't really care that much about where my threshold is set but no matter where I set it, it doesn't seem to reliably ensure peak can always be covered.

I've been adjusting the threshold before and after peak time to try to manually manage it...but maybe I should try to go back to balanced instead?

Maybe you just need to leave it a bit longer (i.e. a month) so it "learns" your environment.

I'm on a ToU plan and my system never starts discharging during Shoulder on weekdays when it is followed by a Peak period. It always waits until the Peak to start discharging.
My system was definitely imperfect in the first few weeks but got into a good set of patterns, that matched my expectations, thereafter.

 

[arnolddeleon]

@dotbombjoe, it was pretty bad for me initially but for the last several weeks it had been getting closer and closer to "perfect". It used to start on the shoulder for me as well but all the energy had come from off peak so it wasn't that bad. It looked like it was trying to find the optimum time to start. It is clearly a tough forecasting problem because there were days when I didn't have the AC load that it didn't start early enough and it still had energy to give after the shoulder after the peak (so missed opportunity). On other days it started discharging a during the shoulder but it ran out of juice before the end of the peak. So it's the not clear cut if the system shouldn't start during the first shoulder. More recently I decided to lower my reserves so the system would have more energy to play with. Now the powerwalls are charging during the shoulder and discharging almost everything during peak. I suspect it will get interesting when the weather cools down.

 

[wwhitney]

OK, this is a bit of a rant, but I had my Powerwalls installed ten days ago, and I find the available reporting and control pretty stupid. A few questions:

1) The graphs and category totals that the app shows for "today" and "yesterday" are very nice. But is there really no way to get Tesla to display the earlier data?

2) If I want a spreadsheet that shows 15 minute energy flow data, is the only option homebrew network polling? What polling frequency will be required? Just looking for the big picture here, I know I can read in the other threads how to set this all up. Tesla must be collecting this information, e.g. for SGIP compliance, has anyone tried asking them to share it?

3) I'm on PG&E EV-A, which is a TOU plan in which there is no weekday off-peak solar production. I believe this must be a pretty common situation for California Powerwall users. So when charging is limited to solar, unless your weekend off-peak solar production exceeds all of your peak consumption for the week, the optimal behavior during weekday part-peak (shoulder) periods is to never discharge and to only charge as required to cover anticipated peak consumption.

Disappointingly, the first Monday on TBC Cost-Saving, the Powerwalls started discharging during part-peak. So those of you with similar rate plans who have had TBC Cost-Saving running for a few weeks, has its behavior converged to the optimal behavior?

Thanks, Wayne

P.S. Some data on my system:

(2) Powerwalls, capacity 27 kWh
Desired reserve = 30%
Usable capacity = 19 kWh
2.4 kW-AC solar system
Currently producing 12 - 15 kWh/day
~ 5 kWh/day peak consumption
~ 5 kWh/weekday part peak consumption

 

[miimura]

Wayne,

Some people above have said that TBC Cost Saving eventually learns and improves so that it charges enough to cover the Peak usage. However, while talking to a Powerwall support rep, I was told that they don't expect Cost Saving mode to work for people who don't have Off-Peak generation available. I use Balanced and I'm very happy with it since it never discharges during morning Part-Peak, always discharges to match usage during Peak (maximizing solar export) and only discharges during the evening Part-Peak when the SOC is high, or it's a Friday and the energy can be replaced with Saturday morning Off-Peak generation. Basically, Balanced does exactly what I want and I don't understand why others want to beat their head against the wall hoping Cost Saving will somehow morph into something more to their liking.

I have a relatively small 4.3kW DC solar system with 2 Powerwalls. Your solar is considerably smaller than mine, so it will take even longer for your solar to recharge your Powerwalls after an outage or a period of higher Peak usage, especially in the Winter.

 

[cwied]

1. I haven't found any way to do this.
2. I'm scared to rock the boat with Tesla support given the reports of their turning off the local Web UI. I have not been impressed with my interactions with Tesla support either. They seem to have canned answers that aren't necessarily accurate and the Tesla rep I talked to would not change their mind even in the face of contrary evidence.
3. With the way cost-based TBC works, it's expected that you would discharge on Mondays. The basic algorithm seems to allocate a portion to peak usage (essentially a "peak reserve) and make sure that it reaches that charge level before peak starts. The end result is the Powerwalls will charge to something less than 100% during the week. On the weekend when you have off-peak energy, they'll charge to 100% if they can. If they end Sunday at higher than the "peak reserve," they'll discharge Monday during the part-peak period. If they're under the "peak reserve," they'll charge instead.
So basically this is approximately their behavior on cost-saving:
-During off-peak: charge
-During part-peak: if over "peak reserve", discharge. If at "peak reserve," standby. If under "peak reserve," charge.
-During peak: discharge to backup reserve.
As far as I can tell, the "machine learning" they're doing is to try to figure out the correct peak reserve value. Editorial: this smacks of over-automation to me, given the limited amount of data and large number of variables involved. My AC usage varies greatly depending on starting temperature in my house and how early in the afternoon the marine layer presses over the hills. I don't think it's likely that Tesla can come up with an accurate algorithm to predict usage, except in aggregate (which doesn't help to control an individual's Powerwalls).

If you want to charge to 100% during the week, use "Balanced" instead of "Cost Saving." I believe that just charges to 100% during part-peak and discharges only during peak. You'll lose the Monday arbitrage, but the behavior will be very similar otherwise except that the charge will be maintained at a higher level during the week.