Charge Powerwall 2 from the grid at certain times

[Bobson11]

I live in the UK and am on Octopus Energy's GO Tariff which means I pay around £0.13pkw during the day and £0.05 between midnight and 4am. I also get paid £0.055 for each kw I export. My ideal setup would therefore be for the Powerwall to charge to 100% between midnight and 4am, so that I am less likely to need any grid energy during peak prices and if I have excess solar it will be exported (at £0.005 more than I have paid to charge the powerwall).

I have been using the cost saving setting in the Tesla app, but it isn't great and often only charges 10% from the grid, sometimes it does more and sometimes it does less. Is it possible, through the API or any other method, to set it to charge to 100% every night between those hours?

Many thanks

 

[Bobson11]

I guess from the tumbleweed that he answer is a simple 'no' then. :-(

 

[wjgjr]

Since a lot of us posters are in the US, it is harder to give an authoritative answer since we are typically not allowed to charge from the grid at all due to rules related to claiming the substantial federal tax credit. In fact, it seems like some here have had trouble getting Tesla to allow it at all, even if they don't claim the credit, because of utility rules and/or because it is easier for Tesla just to disallow it as a policy nationally. Because it cannot be used by most US customers may also be why you are finding it does not work as well as you would want it to.

If you are unable to find a combination of settings in the app to get it working how you want, I would suggest contacting Tesla as one option - it really may be that they just have not spent enough time testing this setup. The other thing to look at is this thread:

Strategies for Powerwalls and Utility Demand Plans

The OP created a SmartThings app for solar/PW to have more control over settings. It is possible that app can do what you want or at least give a good idea of what is possible in the API.

 

[Zer0t]

It's fundamentally arbitraging the rate. I'll charge at non-peak when cheap and discharge during peak when expensive. We'd all love to do that.

 

[jjrandorin]

Sorry, OP.. as @wjgjr said, in the US almost all of us can not charge from the grid by choice if we have solar, and its rare (though not unheard of by any means) for someone to have powerwalls without solar here in the US.

There are a few posters in this section that are outside the US, but either they didnt see your question or know the answer.

This thread has some members that are in the UK in it:

Beware SMETS2 meters

Maybe you could PM a couple of them and see if they know anything about what you are trying to do. You also might be able to do what you want with the smartthings app that @wjgr said.

Good luck!

 

[devachnid]

I'm on Octopus Agile plan and currently use cost-saving mode and set off-peak hours to 13:30-16:00 and peak to 16:00-20:00. This works well most of the time - it'll soak up the solar during the day but will charge from the grid to ensure fully charged before the 16:00 peak. It isn't ideal due to the unpredictable weather here in the UK, so sometimes it'll charge from the grid but then the sun comes out later in the afternoon and I end up paying for grid charging then exporting solar.

I've been playing with the API, particularly to take advantage of the Agile plunge periods and have created a script that checks the half-hourly tariff price and if negative switches the PW over to backup-only mode to force it to charge, then back to cost-saving once the price rises above zero - just waiting for the next plunge period to ensure it works!

As you are on the Go tariff it would be simpler for you as you have a fixed period when you could use the API to switch modes.

 

[Bobson11]

Thanks all, that is really helpful. @devachnid - it sounds like what you have will work perfectly, as I just want it to charge from the grid every night between 1230 and 0400, then to work like normal the rest of the time. Are you able to direct me to the relevant info I'll need to do that? Thanks

 

[devachnid]

@Bobson11 these are the resources I used:

Local API details vloschiavo/powerwall2
Remote API details Commands
Another forum thread https://teslamotorsclub.com/tmc/threads/tou-api.124729/
Octopus API Octopus Energy APIs — Octopus Energy API 1.0 documentation

 

[diyguy]

I’m in California. Here the state has a partial rebate if the Powerwall charges ONLY from the grid. (Self Generation Incentive Program - SGIP). We also have Time of Use (TOU) electric rates. So I’m able to charge off-peak (daytime until 1600, thanks to all the solar pv) and discharge on-peak (1600 to 2100, or 4 pm to 9 pm). The arbitrage doesn’t pay for the Powerwall but does make it makes it more affordable. As mentioned, the federal tax credit only applies to Powerwalls that ONLY charge from home based PV panels. So I had 2 options (solar or no solar) on Powerwall factory settings and had to choose one.
BUT I’m not sure if a second Powerwall could be installed with the opposite setting. I’m considering a second Powerwall and would prefer it to be on the solar option. Anyone with any information on this?

 

[miimura]

I’m in California. Here the state has a partial rebate if the Powerwall charges ONLY from the grid. (Self Generation Incentive Program - SGIP). We also have Time of Use (TOU) electric rates. So I’m able to charge off-peak (daytime until 1600, thanks to all the solar pv) and discharge on-peak (1600 to 2100, or 4 pm to 9 pm). The arbitrage doesn’t pay for the Powerwall but does make it makes it more affordable. As mentioned, the federal tax credit only applies to Powerwalls that ONLY charge from home based PV panels. So I had 2 options (solar or no solar) on Powerwall factory settings and had to choose one.
BUT I’m not sure if a second Powerwall could be installed with the opposite setting. I’m considering a second Powerwall and would prefer it to be on the solar option. Anyone with any information on this?

A two Powerwall system will act exactly like a single Powerwall that has double the energy capacity and input/output power capability. The Gateway commands them in unison.

 

[diyguy]

A two Powerwall system will act exactly like a single Powerwall that has double the energy capacity and input/output power capability. The Gateway commands them in unison.

Thank you, that’s very helpful!