Limit charging of PW2 to set hours

[JoeG57]

Can I limit my Power Wall 2 Charging to set hours.
I'm in NSW Australia and next year the power companies will charge to export power to the grid between 1000 hrs and 1400 hrs
My battery now charges as soon as excess solar is available and is normally fully charged by 1000 hrs so will be penalized around AUD$0.03 per kW export during these hours
Would like to set the charging window so that the solar is exported before 1000 hrs and after 1400 hrs and maximize charging during export cost time
Does any one know if this is possible?

 

[ucmndd]

Time Based Control mode is how you do this.

 

[Redhill_qik]

Time Based Control mode is how you do this.

I don't think that would really work. Maybe you could set a really high import price and a $0.00 export price from 10:00-14:00, but that won't do anything about leaving room in Powerwalls to recharge from excess that they house doesn't use during that time

What is really needed is a setting like pre-PTO that limits any exports. That would still start recharging the Powerwall from sunrise to 10:00, so you might be giving up on maximizing exports. Easiest choice might be to get an EV to charge on the excess solar during that period.

 

[ucmndd]

It would be nice to be able to set negative export values in the utility plan but I don’t think that’s possible.

I’m envisioning a TBC mode with a “peak” period set in the early morning hours that would prioritize sending energy back to the grid until 10:00 and then an off-peak period from 10:00-14:00. I’m not seeing why that wouldn’t work based on my experience with TBC but maybe I’m missing something.

“Export everything” might also be helpful here (if enabled in OP’s system) to make sure the PWs drain to the reserve prior to 10:00.

 

[jjrandorin]

I wonder if there are any differences in what app options the OP gets in Australia, which is where this OP is. OP, have you asked this question in the australia subforum? It fits here in this subforum, but perhaps there is more specific guidance in that subforum?

 

[JoeG57]

I wonder if there are any differences in what app options the OP gets in Australia, which is where this OP is. OP, have you asked this question in the australia subforum? It fits here in this subforum, but perhaps there is more specific guidance in that subforum?

Thanks for your thoughts and replies will look for AU specific site
Joe
PS getting a second PW2 next week so will have some scope for load and storage, looks like this will become a major issue next year when all the Grid/supply gets swamped and the penalty price gets higher
Thanks again

 

[jjrandorin]

Thanks for your thoughts and replies will look for AU specific site
Joe
PS getting a second PW2 next week so will have some scope for load and storage, looks like this will become a major issue next year when all the Grid/supply gets swamped and the penalty price gets higher
Thanks again

What I was referring to was the australian subforum here on TMC. You have posted in it before, but in case its difficult to find (this is a large website) its here:

Australia

teslamotorsclub.com

 

[BGbreeder]

I do think that it can be engineered using Time Base Control. You want to favor Powerwall charging 10:00-14:00 window, and to do that, I think that you want the price of power to be much lower than the price at other hours, e.g. 10% of the price from 14:00-24:00 / 24:00-6:00, set the price 24:00-10:00 to be high to favor self consumption, and you want to set your reserve low enough to empty the Powerwall of whatever power would be generated 10-14:00.

 

[JoeG57]

I do think that it can be engineered using Time Base Control. You want to favor Powerwall charging 10:00-14:00 window, and to do that, I think that you want the price of power to be much lower than the price at other hours, e.g. 10% of the price from 14:00-24:00 / 24:00-6:00, set the price 24:00-10:00 to be high to favor self consumption, and you want to set your reserve low enough to empty the Powerwall of whatever power would be generated 10-14:00.

Just tried time of day giving off peak zero cost and Peak $0.36 SAME RESULT starts charging from excess solar as soon as sun up
will now try using sell price as well

 

[BGbreeder]

FWIW: Others have noted that 0.00 for a price seemed to confuse the Powerwall algorithm. The other item that I would share is that one sometimes have to give the system a couple of days on the new pricing to adjust its behaviour.

All the best,

BG

 

[miimura]

It seems to me that the real solution to avoid export penalty is to configure the solar inverters to curtail generation when there is net export. I know there are inverters that can do this because they are deployed in places like Hawaii that have tariffs that completely disallow exporting. The question is whether those inverters have the concept of time-based export limits.

 

[JoeG57]

FWIW: Others have noted that 0.00 for a price seemed to confuse the Powerwall algorithm. The other item that I would share is that one sometimes have to give the system a couple of days on the new pricing to adjust its behaviour.

All the best,

BG

Yep just noticed behavior is changing as the battery now seems to jump in and supply load leaving export steady then taper off and recharge from the solar

 

[JoeG57]

It seems to me that the real solution to avoid export penalty is to configure the solar inverters to curtail generation when there is net export. I know there are inverters that can do this because they are deployed in places like Hawaii that have tariffs that completely disallow exporting. The question is whether those inverters have the concept of time-based export limits.

Tried the Tesla PW2, Settings "go off grid" feature it stops export dead and balances load between battery and Solar , so Tesla can do it all if it wants to just need the correct algorithm plenty of time before the charges start

 

[bruce_miranda]

Here is what I do. I have my Peak and Off Peak times and Import rates set. The Export rate for both time slots is set to 0. This works correctly and the PW charges on the Off Peak time/rate and then discharges when the Peak time kicks in.
I then use Home Assistant and the Solar Forecast integration to estimate how much Solar I might get during the next day. Based on that answer, I keep some of the battery left uncharged during the Off Peak time, so that I can soak up any excess Solar produced during the following day.
Its not perfect but works extremely well.

 

[Mark Purcell]

Aussie powerwall user here.

I achieve morning exports and delayed charging using TBC and defining a morning and evening peak. The battery will export during the morning peak, or if you switch Exports Solar Only then it will export solar that isn't consumed by your household load.

You can see below exporting (3x 5 kW powerwall) + excess solar before 8:10am when the feed in price was positive, after 8:10am the feed in price went negative so my Home Assistant switched to Self Powered.

 

[JoeG57]

Aussie powerwall user here.

I achieve morning exports and delayed charging using TBC and defining a morning and evening peak. The battery will export during the morning peak, or if you switch Exports Solar Only then it will export solar that isn't consumed by your household load.

You can see below exporting (3x 5 kW powerwall) + excess solar before 8:10am when the feed in price was positive, after 8:10am the feed in price went negative so my Home Assistant switched to Self Powered.
View attachment 990855

View attachment 990856

The graphic you have supplied seems very different to what I have and I can't seem to duplicate it with my Tesla app on my phone.
How did you set this up?
regards
Joe

 

[Mark Purcell]

The graphic you have supplied seems very different to what I have and I can't seem to duplicate it with my Tesla app on my phone.
How did you set this up?

This graphic was from Home Assistant, which lets me show which mode and zoomed in power flows.

Here is the same day in the Tesla app, see the deferred charging from 6am - 8am.

 

[JoeG57]

Aussie powerwall user here.

I achieve morning exports and delayed charging using TBC and defining a morning and evening peak. The battery will export during the morning peak, or if you switch Exports Solar Only then it will export solar that isn't consumed by your household load.

You can see below exporting (3x 5 kW powerwall) + excess solar before 8:10am when the feed in price was positive, after 8:10am the feed in price went negative so my Home Assistant switched to Self Powered.
View attachment 990855

View attachment 990856

OK I have finally made the Time of Use and Pricing work so the Powerwall is only charging from Solar between 1000 hrs and 1400 hrs so that part is now working just need to make the Tesla system export limit once the negative pricing comes in next year.
Plenty of time so should be worked out in plenty of time.
Thanks every one for your help