Hi everyone.
For 3 weeks I am trying to find a solution for my Octopus Agile behaviour. I was fighting with the support but they are more interested in just dodging me than trying to look into the problem. I wanted to compare my Powerwall behaviour with others.
The setup: my Powerwall is set to Time-Based Control (Savings mode), connected with Octopus Agile directly through the Tesla app, no 3rd party controls, grid charging allowed, export set to everything. I am on Prime Outgoing Octopus for exports with 9p/kWh during the day and 16p during the peak 4pm-7pm. 4kW solar array with 3.6kW inverter. I do not change settings, and have no 3rd party control enabled on the battery for the last few months.
The problem: My Powerwall charges from solar, always ignoring upcoming off-peak prices, like they do not exist. For example, prices will drop below 7p/kWh to 4p/kWh in 2 hours, Powerwall is at 40%, solar forecast is at max, no clouds, and the Powerwall charges itself instead of exporting the excess to the grid. It will just go up to 100% charge like that (does that even when the prices are negative or 1p/kWh) and will sit idle for the rest of the day. But when peak prices come, the Powerwall continues to sit idle even when the solar production drops below house consumption, and I will be importing from the grid at prices of 35-40p/kWh. That happens until about 8pm, after which it will power the house for the rest of the night. In the morning around 8am, with the charge around 50-60%, it will stop providing power to the house and I will import during morning peak hours.
Support told me to wait, that it is "adapting". 3 weeks and the behaviour hasn't changed a bit. I was connected to a "technician", who first failed to see imports and sent me a graph which showed solar production at 3kW at the specified by me import time, which is impossible for my solar array at that time production with clear skies won't exceed 2.5kW. I demonstrated to him in real time on the call how my house imports from the grid with a load > 1.5kW in peak times (35p/kWh). So he sent me an "article" about why Powerwall can sit idle and "efficiencies in conversion", but no efficiency can explain the reasoning behind a 35p/kWh import to save for a later export at 16p/kWh. He complained about Home Assistant and tried to blame me for managing the battery through the local API, which they removed 2 years ago from Powerwall 2, and I am not managing the battery through the Fleet API either. At the end, he told me that they can't diagnose the issue as it is AI, it is Opticaster and they can't see why it is doing this, but "if it is doing this, it is correct".
If you have a similar setup, can you share how the Powerwall behaves for you, maybe in PM? Just want to see what to do next.
Before you recommend me to switch to another tariff, it doesn't help much. On Economy 7 it ignored off-peak charging, leaving space for solar, but didn't charge from solar because the export price was high, so it was empty by the evening and I was importing at peak times.
Thank you, and sorry for long read.