Interesting thread. I’ve encountered similar frustrations/head-scratching with TBC which is why I no longer use it. Its black-box algorithm does weird and unpredictable things and I don’t like it. Also, since the input data does not include the rate for feed-in-tariffs, nor for 100% green power grid surcharges, I don’t believe it can properly optimise. A cost optimisation algorithm can’t work on incomplete input data.
By importing all my 5-minute PW2 data and doing “what-if” calculations comparing how TBC did work to other possible algorithms and what would they have done, I came up with a simple set of rules that I think work slightly better than TBC in terms of optimising cost (at least for my generation/usage profiles), but also have completely predictable behaviour and most importantly the user will understand what the system will do.
So I’d like Tesla to add a “Simple Optimised Control” on top of the Self-Consumption and TBC options. SOC would have self-consumption as its underlying mode of operation but with 3 simple toggles that modify it:
- Do not discharge the battery during off-peak
- Fully charge the battery from the grid before the end of the off-peak period
- Fully charge the battery from the grid before the end of the shoulder period (or partial peak as you call it in the USA)
Each option includes the option above it, hence they are increasingly aggressive in terms of trying to keep your battery full and minimise use of grid power during peak times.
Because so many houses in Australia have rooftop solar now (about 30%) there has been a collapse in feed-in-tariffs. I used to get 21c/kWh, it’s now down to 2.5c/kWh. It will likely soon be zero and then potentially we will have to start paying to export at certain times of the day when there’s simply too much electricity.
So increasingly you actually don’t want to export but keep as much power for yourself (self-consumption) and have additional control to minimise peak grid usage and use the battery to tariff shift. That’s what this 3-stage toggle would do.