Permanent battery power keeps the Android system in a low power state rather than fully off, so the screen wakes in roughly 1 to 2 seconds when you turn the ignition on instead of cold booting.
This is the single biggest difference between an install that feels factory and one that feels like an aftermarket tablet. A cold boot from full off takes long enough that the driver is moving before the cluster is live.
How the two feeds work together:
| Feed | Purpose |
| Permanent 12V from battery | Keeps the system in standby so it wakes fast |
| Switched ignition | Tells the screen to wake and to sleep |
| Ground | Reference for both |
If the vehicle is stored for long periods, fit a battery isolator or a maintenance charger. Standby draw is small but it is not zero.
Related: Power Wiring: Battery, Ignition and Ground · My Screen Is Slow to Boot · My Screen Stays On After I Turn Off the Ignition
