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Are these operating modes possible?

RKCRLR

Member
Apr 13, 2020
465
191
Garden Valley, CA
Have you tried “Self Powered”? This is what our system behaves like.

As generation kicks in in the morning, it starts feeding the house (with batteries supplying remainder). Once solar can take over fully, any remainder goes to batteries. Eventually batteries charge to full, and solar feeds house and grid.

As the sun starts going down, solar + batteries are used, eventually switching to battery only. There’s no time-based control (peak etc) but it’s not necessary if you have enough battery to get you at least through the peak period.
The only time I want any power coming from the Powerwalls is 4-9pm (unless there is a power outage).
 

RKCRLR

Member
Apr 13, 2020
465
191
Garden Valley, CA
T
Pull the start of the Peak period earlier to avoid the grid pull. When the SOC is really high, Balanced will use PW energy during Off Peak. This is one thing that I wish had a setting to completely block. Since I'm on PG&E EV2-A I don't mind the PWs draining between 9pm and midnight because that is the Part Peak rate and the vast majority of my generation happens during Off-Peak before 3pm.

This chart is typical for my system this time of year. I would like to avoid the morning discharge, but it's not a lot of energy. It's almost like it goes into a Self-Powered like mode as soon as the solar starts generating. You can also clearly see that it is not regulating the PW discharge as tightly during the nighttime Part Peak as it does during Peak. During usage spikes the discharge does not follow closely, resulting in some grid draw.

View attachment 672232
The problem with starting Peak earlier in Balanced is it will send all solar to the grid and none to the house just like Cost Saving. If I wanted that I could just stay in Cost Saving to avoid discharging the Powerwalls Off-Peak.
 

arnolddeleon

Supporting Member
Supporting Member
Jul 21, 2012
894
948
SF Bay Area
Results of day 2 pretty much the same as day 1.
What do you have reserved set at? What was the SOC at the end of peak?

The system pulling from the grid during park peak *and* discharging during off peak are somewhat contradictory data points. The former would indicate the system wanting to hold to energy for use during a better period of time. The latter indicates it had energy to burn. Can you post a screenshot of how it looked?
 

RKCRLR

Member
Apr 13, 2020
465
191
Garden Valley, CA
What do you have reserved set at? What was the SOC at the end of peak?

The system pulling from the grid during park peak *and* discharging during off peak are somewhat contradictory data points. The former would indicate the system wanting to hold to energy for use during a better period of time. The latter indicates it had energy to burn. Can you post a screenshot of how it looked?
I have my reserve set at 50%. This lets me get through the hottest/coldest days before hitting my reserve during peak hours (4-9pm). Due to a combination of a mild day, prioritizing solar to the house (good), and and drawing from the grid during peak (bad), my SOC was above 90% at 9pm.

Below is a SOC chart taken today around 6pm:

1623460457219.png


Below is the power data for yesterday:
1623460695954.png
 

getakey

Active Member
Jan 28, 2020
1,412
451
95762
I think you are over thinking this. Set on Cost Savings and set Peak 4 to 9. Set all other time Off Peak, i.e., no Shoulder. You will only pull from PW during Peak. Your PWs will charge in the AM and then Solar will power house with excess to grid.
 
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RKCRLR

Member
Apr 13, 2020
465
191
Garden Valley, CA
I think you are over thinking this. Set on Cost Savings and set Peak 4 to 9. Set all other time Off Peak, i.e., no Shoulder. You will only pull from PW during Peak. Your PWs will charge in the AM and then Solar will power house with excess to grid.
That's where I started from. And it works great except solar is prioritized to the grid instead of my house. So I incur unnecessary NBCs and Powerwall discharging. That is what I'm trying to eliminate. But, unfortunately, Cost Saving looks to be the least of the evils.
 

h2ofun

Active Member
Aug 11, 2020
2,932
562
auburn, ca
That's where I started from. And it works great except solar is prioritized to the grid instead of my house. So I incur unnecessary NBCs and Powerwall discharging. That is what I'm trying to eliminate. But, unfortunately, Cost Saving looks to be the least of the evils.
I am in balanced and run my house 99% off the grid from the batteries and solar. Minimized NBC's. This powerwall discharging is, well, ....
 

RKCRLR

Member
Apr 13, 2020
465
191
Garden Valley, CA
I am in balanced and run my house 99% off the grid from the batteries and solar. Minimized NBC's. This powerwall discharging is, well, ....
Yes, but you don't care if your Powerwalls don't last beyond 10 years. I'm trying to maximize their life since they are mainly for backup and I don't want to have to replace them sooner than necessary.
 

h2ofun

Active Member
Aug 11, 2020
2,932
562
auburn, ca
My conclusion so far is my goals can't be achieved with the current operating modes. But several people have said I should try different modes so I'm trying to go into this with an open mind.
i have yet to read anyone saying what you are asking for is possible. good luck. i just need to spend my life on more than this battery solar stuff. but just me
 

arnolddeleon

Supporting Member
Supporting Member
Jul 21, 2012
894
948
SF Bay Area
I have my reserve set at 50%. This lets me get through the hottest/coldest days before hitting my reserve during peak hours (4-9pm). Due to a combination of a mild day, prioritizing solar to the house (good), and and drawing from the grid during peak (bad), my SOC was above 90% at 9pm.

Below is a SOC chart taken today around 6pm:

View attachment 672407

Below is the power data for yesterday:
View attachment 672410
I think the pulling from the grid during the transition is going to be very hard to fix. On the graph above I think it did about as well you can hope. If it was me I would push my peak a little earlier and err on the side of selling a little versus buying a little.

That leaves dealing with the discharge during off peak. In balanced mode I believe if there is excess energy it will discharge in the off peak it thinks it can "break even". I think there are two ways to try to fix that.

Option 1: increase the reserve

Option 2: add more shoulder in the afternoon (e.g. start park peak at 1:00 pm) the idea is to make the system more reluctant to pull the off peak energy out of the batteries at night because it can't replace it with off peak juice. The first time I made this recommendation I think I was too aggressive in trying to trick the system by suggesting a super early part peak. I was trying to actually have it charge during part peak, I think that's not needed.
 

getakey

Active Member
Jan 28, 2020
1,412
451
95762
That's where I started from. And it works great except solar is prioritized to the grid instead of my house. So I incur unnecessary NBCs and Powerwall discharging. That is what I'm trying to eliminate. But, unfortunately, Cost Saving looks to be the least of the evils.
if solar is prioritized to the grid, how could you be incurring more NBCs? You aren't pulling from the grid when solar is going to the grid. If you don't want to pull from your PW, increase your reserve. But, saving your PWs lifespan is going to incur more from the grid. I just don't see what you are trying to accomplish
 
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RKCRLR

Member
Apr 13, 2020
465
191
Garden Valley, CA
if solar is prioritized to the grid, how could you be incurring more NBCs? You aren't pulling from the grid when solar is going to the grid. If you don't want to pull from your PW, increase your reserve. But, saving your PWs lifespan is going to incur more from the grid. I just don't see what you are trying to accomplish
You're correct now that I think about it, when solar when solar is prioritized to the grid and the home is running off the Powerwalls then there aren't additional NBCs but there is unnecessary discharging of the Powerwalls since the home could be running off solar. So I want the solar production prioritized to the home during the hours of 4-9pm. I forgot that the Powarwalls only charge from solar.

So this makes Cost Saving mode look better for my situation than I first thought (If my current thinking is correct - this gets confusing). Cost Saving mode doesn't incur additional NBCs but does cause more discharging of the Powerwalls than necessary during Peak and Shoulder periods.
 

RKCRLR

Member
Apr 13, 2020
465
191
Garden Valley, CA
You're correct now that I think about it, when solar when solar is prioritized to the grid and the home is running off the Powerwalls then there aren't additional NBCs but there is unnecessary discharging of the Powerwalls since the home could be running off solar. So I want the solar production prioritized to the home during the hours of 4-9pm. I forgot that the Powarwalls only charge from solar.

So this makes Cost Saving mode look better for my situation than I first thought (If my current thinking is correct - this gets confusing). Cost Saving mode doesn't incur additional NBCs but does cause more discharging of the Powerwalls than necessary during Peak and Shoulder periods.
I should clarify the above only applies to the Peak hours. Cost Savings mode still incurs unnecessary NBCs during the morning by prioritizing Powerwall recharging over home consumption thus requiring the house to draw from the grid while the Powerwalls are recharging.
 

RKCRLR

Member
Apr 13, 2020
465
191
Garden Valley, CA
I think the pulling from the grid during the transition is going to be very hard to fix. On the graph above I think it did about as well you can hope. If it was me I would push my peak a little earlier and err on the side of selling a little versus buying a little.

That leaves dealing with the discharge during off peak. In balanced mode I believe if there is excess energy it will discharge in the off peak it thinks it can "break even". I think there are two ways to try to fix that.

Option 1: increase the reserve

Option 2: add more shoulder in the afternoon (e.g. start park peak at 1:00 pm) the idea is to make the system more reluctant to pull the off peak energy out of the batteries at night because it can't replace it with off peak juice. The first time I made this recommendation I think I was too aggressive in trying to trick the system by suggesting a super early part peak. I was trying to actually have it charge during part peak, I think that's not needed.
Increasing the reserve won't work for me unless I wanted to manage it daily (which I don't).

I don't think there are any settings in Balanced mode that will make the Powerwalls stop discharging at 9pm and not discharge again until 4pm the following day. I think the gap is just too big.
 

RKCRLR

Member
Apr 13, 2020
465
191
Garden Valley, CA
Day 1 of Shoulder set to 4-8pm and Peak to 8-9pm in Balanced mode results:

During the day the house was running off solar with the excess going to the grid (good).
At 4pm the house continued to run off solar with excess going to the grid (good).
Around 7pm the solar couldn't keep up with the house demand and excess was being drawn both from the grid (bad) and the Powerwall (good).
At 8pm all power was coming from the Powerwalls (good).
At 9pm the Powerwalls were still over 90% SoC but then the house began running off the Powerwalls throughout the night (bad).
Around 7:30am the Powerwalls were down to 55% SoC when the solar started generating. The house was then running off the solar with the excess going recharging the Powerwalls (good) until around 11am when the Powerwalls were fully recharged.

So far, this is almost the opposite of what I'm looking for (I don't want it pulling from the grid during peak hours and running off the Powerwalls at night).
The results of days 2 and 3 were pretty much the same as day 1. I don't see any evidence of a trend that would lead me to believe that this would improve if I gave it more time.

At this point I don't see any way of accomplishing the following:

1) Only allow discharging the Powerwalls during the hours of 4pm-9pm.
2) Prioritize solar going to the home over the grid during the hours of 4pm-9pm.
3) Prioritize solar going to the home over recharging the Powerwalls during all hours outside of 4pm-9pm.

So, back to Cost Saving mode since it at least accomplishes item 1.
 

RKCRLR

Member
Apr 13, 2020
465
191
Garden Valley, CA
But, saving your PWs lifespan is going to incur more from the grid. I just don't see what you are trying to accomplish
I'm an excess producer. I don't mind pulling from the grid during off-peak when no solar is being produced. I'm only compensated ~$0.03/KWh for the additional throughput from the Powerwalls.
 
Last edited:

warjcowski

Member
Apr 22, 2021
12
6
Bay Area, CA
The results of days 2 and 3 were pretty much the same as day 1. I don't see any evidence of a trend that would lead me to believe that this would improve if I gave it more time.

At this point I don't see any way of accomplishing the following:

1) Only allow discharging the Powerwalls during the hours of 4pm-9pm.
2) Prioritize solar going to the home over the grid during the hours of 4pm-9pm.
3) Prioritize solar going to the home over recharging the Powerwalls during all hours outside of 4pm-9pm.

So, back to Cost Saving mode since it at least accomplishes item 1.
In this scenario, when do you charge your powerwalls? I can't think of a scenario where 1 and 2 can be true at the same time.

Have you tried cost savings with:

Peak 4-9 (use powerwalls, but export solar)
Off peak: 9 to 8a (use grid)
Shoulder: 8a-4 (prep for peak by using grid to power and solar to charge)
 

RKCRLR

Member
Apr 13, 2020
465
191
Garden Valley, CA
In this scenario, when do you charge your powerwalls? I can't think of a scenario where 1 and 2 can be true at the same time.

Have you tried cost savings with:

Peak 4-9 (use powerwalls, but export solar)
Off peak: 9 to 8a (use grid)
Shoulder: 8a-4 (prep for peak by using grid to power and solar to charge)
The Powerwalls would get charged from the excess solar that the home doesn't consume in the morning. There would need to be some AI involved like in Balanced mode where the system would recognize if there isn't enough solar being diverted to fully recharge the Powerwalls before the next Peak period and then prioritize the Powerwalls.

I'm going back to Cost Saving with Peak set from 4-9pm and Off-Peak at other times. My experience with Cost Saving Shoulder is it will allow discharging the Powerwalls to the home. I don't want that happening during off-peak hours.
 

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