DHW control parameters and logs and script
A script on the main Raspberry Pi runs every 10 minutes to compute target maximum heat-battery top-up level from the grid. This depends on a a number of factors such as time of day, grid carbon intensity, and sunshine forecast.
The heat-battery system is a Sunamp Thermino powered via a myenergi eddi.
Note:
YYYYMMDD.log
YYYYMM.log.gz
After being deeply discharged (to almost ~12°C mains inlet temperature) during the 17th, eg by baths etc, and not topped-up up because of high grid carbon intensity for a couple of days... (And no diversion!)
Overnight from a fraction before midnight until ~6am over 9.4kWh was absorbed by the Thermino at ~120gCO2e/kWh grid intensity. That is 'full' in terms of the indicator lights on the Thermino, but not to the point where the heater relay turns off.
There was a small space of ~20 minutes at the end of topping up where it would still have been permitted, but was not needed.
(There were 16 minutes in which frequency response cut in, and top-up stopped, including a little cluster around the turn of 5am.)
This is an outline of the part of the heat-battery control algorithm that sets the maximum top-up level from mains, as of just over 1 year's system operation. Most elements seem to be working reasonably well at this point, after tuning through all seasons.