The electric power steering pump (EPS) draws high currents, so if the ignition is left on the battery is quickly drained. I've also installed an LC-2 wideband controller, which should not powered/heated without the engine running
Do not pre-warm the sensor before starting the engine, simply start the engine as normal. Allowing the sensor to pre-warm before starting the engine will increase the possibility of damaging the sensor from shockcooling.
I came up with the idea of using a voltage monitor, so that the LC-2 and the EPS only receives power when the starter battery is charging - indicating that the engine is running. The voltage monitor has two configurable set-points, a start voltage and a cut-off voltage.
The voltage monitor controls a relay supplying the LC-2 and the EPS directly from the starter battery, as recommended by Innovate.