Advanced: Cost Saving Hack to maintain PW2 at peak capacity

[Frankman60]

Thanks power.saver and MorrisonHiker.

 

[NinjaVece]

I am getting ready for 2 PWs to be installed later this year and am trying to relate the “Hack” by NinjaVece to my SDG&E TOU periods. Peak is 4 to 9 PM every day of the week. However, the Off Peak time periods are different on weekdays and weekends. Off Peak is 12 AM to 6 AM weekdays, and 12AM to 2 PM weekends. The PWs have more than enough capacity to fully cover all of our Peak period usage so all solar generation during Peak should be exported to the grid. I would prefer that the PWs do not discharge at all during Off Peak. Will the “hack” be necessary to do this or can I just run the Balanced or Cost Savings TBC profiles?

Frankman60, if you only want to discharge during Peak periods, you need to stay with Cost Saving mode. For your weekends, if you want the PW2 to recharge to 100% on Saturday (versus wait till Monday) after Friday's discharge, you will need my hack to make it occur. You only sacrifice a half hour to discharge each day on the weekend and it is late (I have mine set at 8:30pm to 9:00pm) so only a small amount of discharge occurs (I get about 5% use to 95%). That amount is easily refilled on Sunday and Monday morn and you have the advantage of a weekday (Monday) starting with basically a fully charged system.

However, if SDG&E has Peak all week, it may work differently.

Let me know if you have any questions.

 

[NinjaVece]

You won't need this since you have a peak period every day. It's only necessary for those of us that don't have a peak period on the weekend and want to force the PW to charge when it otherwise wouldn't.

Power Saver, my experience is that the PW2 treats the Weekend differently than Weekdays. Are you sure that the PW2 will recharge during Shoulder-Peak periods on the Weekend if there is a Peak period?

 

[power.saver]

Power Saver, my experience is that the PW2 treats the Weekend differently than Weekdays. Are you sure that the PW2 will recharge during Shoulder-Peak periods on the Weekend if there is a Peak period?

When I had shoulder on weekends, it charged. I had the problem when there was only off-peak on weekends.

 

[voltronhb]

We have solar and were thinking about getting Powerwall. We have NEM and wanted to have solar go to the grid during peak and off peak hours. Can the PW discharge during peak and off peak and have solar production sent to the grid? If so, does it mean that electricity at home is prioritized to use the PW, then solar and then the grid? If there isn't enough solar to charge the PW, does it charge from the grid during shoulder hours?

 

[miimura]

We have solar and were thinking about getting Powerwall. We have NEM and wanted to have solar go to the grid during peak and off peak hours. Can the PW discharge during peak and off peak and have solar production sent to the grid? If so, does it mean that electricity at home is prioritized to use the PW, then solar and then the grid? If there isn't enough solar to charge the PW, does it charge from the grid during shoulder hours?

In the USA, PW never charges from the grid.
With Time Based Control, the PW will power the house during Peak and let all the solar go to the grid to earn the high priced NEM credits. What happens during shoulder periods between peak and off-peak depends on the hours and how much solar generation you have during off-peak and shoulder and what the battery SOC is. It also depends on whether you're using Cost Saving or Balanced mode. Most people with NEM and TOU rates don't want the PW to discharge during off-peak at all.

 

[GenSao]

In the USA, PW never charges from the grid.
With Time Based Control, the PW will power the house during Peak and let all the solar go to the grid to earn the high priced NEM credits. What happens during shoulder periods between peak and off-peak depends on the hours and how much solar generation you have during off-peak and shoulder and what the battery SOC is. It also depends on whether you're using Cost Saving or Balanced mode. Most people with NEM and TOU rates don't want the PW to discharge during off-peak at all.

Also note, the PW will charge from the grid when Storm Watch mode is enabled. "Powerwall communicates with the National Weather Service to know  when  severe weather is on the horizon and automatically triggers Storm Watch. This mode pushes the limits and charges Powerwall to maximum capacity so it can provide backup power. "

With the exception of Storm Watch, you PW will not charge from the grid. This is done so that your PW costs qualifies for the 30% federal tax credit.

 

[CWheels]

Also note, the PW will charge from the grid when Storm Watch mode is enabled. "Powerwall communicates with the National Weather Service to know  when  severe weather is on the horizon and automatically triggers Storm Watch. This mode pushes the limits and charges Powerwall to maximum capacity so it can provide backup power. "

With the exception of Storm Watch, you PW will not charge from the grid. This is done so that your PW costs qualifies for the 30% federal tax credit.

My Powerwalls actually DID charge up from the grid AND from solar at the same time, in the hour leading up to Peak Period, and trying to fill the PWs to as close to 100% as possible. I didn't think it was possible to charge from the grid, but I guess it is.

 

[zanary]

My Powerwalls actually DID charge up from the grid AND from solar at the same time, in the hour leading up to Peak Period, and trying to fill the PWs to as close to 100% as possible. I didn't think it was possible to charge from the grid, but I guess it is.

It's technically possible, however the ITC rules prevent Tesla from doing this unless certain conditions like StormWatch is activated. Why it did it in this case may be unknown...