Original link :https://community.home-assistant.io/t/heat-the-water-heater-using-solar-surplus/743372

This article mainly proposes a solution for the second method and includes two parts.

• Add a controller (SCR-485) to Home Assistant that can linearly adjust the power of resistive loads (such as a water heater).
• Create an automation so that the SCR-485 adjusts the power output based on the real-time grid power.

I might get involved in this if you want, as my previous automation was reacting every second to power changes

So I converted to HA controlling this, tried to adjust this to 1 second reaction, and not sure how good it worked, it was similar to doing it with the SCR-485, where the power set was all over the place, setting output to max a number of times then dropping back to where the load and solar actually was. This behaviour is worse earlier in the morning, but over all worked well.

Is it possible in these automations to have the start and end times and the refresh time (interval) as variables you can set in Home Assistant rather than hard coded?

If you find it troublesome to modify the time from settings->automations&scenes->Auto SCR->And if, the following method will use variables to set the time on the dashboard.

1. Add at the end of configuration.yaml

input_datetime:
start_time:
name: Start Time
has_date: false
has_time: true
initial: '07:00'
end_time:
name: End Time
has_date: false
has_time: true
initial: '17:00'

2. Go to settings->automations&scenes->Auto SCR->And if and change the two times to the two variables you added

Then save

3. Add these two time entities to the dashboard

type: vertical-stack
cards:
- type: entities
entities:
- entity: switch.scr_ha_with_battery
- entity: sensor.tmp_grid_power
- entity: number.scr_485_5_threshold
- entity: number.scr_485_5_hysteresis
- entity: number.scr_485_set_power
- entity: input_datetime.start_time
- entity: input_datetime.end_time
- type: history-graph
entities:
- entity: sensor.tmp_grid_power
- entity: number.scr_485_set_power
hours_to_show: 1