Adjust Tesla charge rate from mobile app, API & PW2 to allow use of excess solar

[doggy1]

What would be really great is to have heaps of these:

Snowy Hydro 2.0 — but 'much, much' smaller

An energy storage project dubbed the world's smallest version of the Snowy Mountains hydroelectric power plant is taking shape in Western Australia.

www.abc.net.au

 

[lonertic]

I disagree that it's "being good" in the sense of producing an unambiguously overall positive outcome.

What matters for the 'greater good' is the overall level of demand being served by solar (or really, RE / low-carbon generation). Turning your car charger on and off based on your local solar production isn't actually changing the level of solar production, unless you're export constrained, so it's net neutral.

you misunderstand - I'm in an area where solar output greatly exceeds demand during the day. I've started getting negative FiT for exporting to grid. In my case (can't speak for others), my intended solution is to soak up excess solar that has literally nowhere else to go but to get wasted.

1) Grid is already at full export capacity (I can see the grid input power is over 255vac!! It's overloaded!)
2) My home solar battery banks are ALSO at full capacity.. all banks at 100%..
3) ** This is where I want to start charging on my Tesla, any additional excess power generated from my PV that shouldn't go to grid, and can't fit in my home battery anymore - That goes into the CAR! So at least I can use it for transport.
4) This is next phase - once the CAR is also fully charged (90%), the power again has nowhere to go, my current plan is to simply command the inverter to disconnect from grid and run in island mode. Which means the house is powered 100% by PV and the home batteries act like a capacitor to smooth the output curve - then in a more distant future state (maybe a year or 2 from now?), if i STILL have excess PV left over, that goes into local Hydrogen production. Excess hydrogen will be converted into ammonia to be stored in liquid form without risk of high pressure kabooms.

Because of condition 1 - if the FiT is a positive price, that means the grid actually needs my power. That's when I'd export any excess to grid. Hence, "being good".... Part of "being good" also involves recognising when your contribution to the grid is going to have an adverse effect and blow some equipment up, therefore move onto condition 2,. 3,.. so on so forth.

 

[modus0p]

Just wanted to say I've managed to set up 'smart solar charging'.

So for others interested in doing so what I have is:
1. standard 15A power point with the Universal Mobile Charger.
2. An IotaWatt which amongst other things measures the entire house consumption and the solar production (it also monitors the tesla 15A circuit but thats not actually needed).
3. Home Assistant set up and information from the iotawatt is fed in. I also have the Home Assistant Custom Tesla Integration which allows me to control the car (including the new amperage adjustments).
4. A simple automation in Home assistant which every minute (provided the car is at home and charging) looks at the difference between house consumption and solar production and adjusts the car charge rate to try and remove the difference. Then I have a simple switch in the home assistant interface to turn this smart charging on or off.

Here is the yaml for the change in amps:

service: tesla_custom.api data: command: CHARGING_AMPS parameters: path_vars: vehicle_id: '{{ state_attr("binary_sensor.electra_carmen_online_sensor", "id") }}' charging_amps: >- {{ [[((states("sensor.tesla_charger_actual_current")|int) + ((states("sensor.solar")|float - states("sensor.consumption")|float) / 240)|int),0]|max,15]|min }}

 

[James_B]

@modus0p thanks for this. I've just set up something similar. It's not quite as accurate, but gives a good approximation.

I've got a free PowerPal, which shows net usage within the house. I have the actual solar values coming in from the inverter, so when the Powerpal hits 0 KWh usage, that means I'm starting to export, so then I take the base load of the house off (~750W) and charge based on the available solar. It's working well so far and I'm going to add a few individual wifi power meters on the larger appliances to measure their usage, such that if they're turned on, it will take that into account in the available power. The only thing it won't take into account is the oven being turned on, but it will stop charging when that happens.