To have clear boundary, the LED controller has to read the voltage of the d1... and "forward" it for the UI on MQTT /OpenRace/led/<MAC>/voltage.
Also the LED controller has to calculate the cell voltage and tell the UI if the voltage is critical, by setting /OpenRace/led/<MAC>/voltage_critical to (string) true or false.
To have clear boundary, the LED controller has to read the voltage of the d1... and "forward" it for the UI on MQTT
/OpenRace/led/<MAC>/voltage
. Also the LED controller has to calculate the cell voltage and tell the UI if the voltage is critical, by setting/OpenRace/led/<MAC>/voltage_critical
to (string) true or false.