For new the first strategy is: Grid Aware
Requires: P1 meter, Solar inverter
Controls: Battery and EV charger
Input: Weather prediction, solar production prediction EV SOC
How it works, but you can manage a lot:
Main operation
When surplus starts to occur (production exceeds house use) it uses the EV threshold to either prioritize the battery (low surplus is efficient for batteries) OR it prioritize the EV charging. This prevents the battery from competing with the EV.
You can then set a max for the EV charging, when the surplus grows over the max value it will start to include the battery. This threshold bandwidth creates a stable consumer for your surplus.
When the surplus ends by going down at the end of the day, it first stops the battery, then the EV and the remainder goes into the battery. If the battery might already be full, it keeps the EV charging.
Goal: Ensure at the end of day the battery is fully loaded, and the remainder has been send to the EV.
Exception: EV is not present
When this happens the battery is handled with a grid zero operations (by the HEMS). This means it will unload to handle peaks and loads while surplus is available, optimizing the max amount it can store during the day.
Grid awareness
During the surplus hours the grid is overloaded, so the HEMS prevents your house to send additional surplus to the grid. It ensures it only charges and charges (unless everything is full or the EV is not available then it tries to stay at 0). When the shortage hours start (expensive hours, morning evenings) it will use the battery to keep the import low. It will do this till the battery is drained to your safety margin bottom (settable).
It will stop doing this when the expensive hours are done and there is still left, it will safe that till the next peak.
This should stabilize your power usage to a rather nice average.
Influance
You can have influance on the system using modes like ‘EV will be used’. This will tell the HEMS the car WILL leave later on and safes the battery by prioritize the EV with all surplus.
And it will allow for a lower safety margin for the battery SOC, doing this in the morning or night will allow the first expensive period to drain the battery more creating more space for the upcoming sunny day (depends on weather prediction).
EV SOC the car will be used will trigger a night charge cycle to ensure your car is charged to the target SOC, this can be made dynamic by flows. The charge speed is calculated to ensure you hit the goal with the lowest speed the charger can do, preventing load on your grid.
Example
You will get this behavior.
Battery was at its low during the day start, so the morning was all import then when the sun started you see the nice green solar curve in different energy flows. Around it small imports. During the day the grid is overloaded with surplus, so import is cheap and helps the grid, so the HEMS preffers to import over export keeping a safe margin there.
When the sun went down, the battery took over.
The lower darker green is solar power used by the house
The middle green is solar power pushed into the EV charger
The light green top is solar power stored in the battery.
The teal is the house running from the battery.
Multiple widgets included
