This is a high quality module that senses the rise in battery voltage when an engine is running, and gives various outputs.
The module has many ways of being wired, dependent on what you’d like to be activated.
If you need the outputs to be switched off as soon as the engine stops running, then an ignition input can be used. With this method with the ignition turned the outputs would activate when the voltage rises above 13.5v. When the ignition is turned off the outputs would immediately de-activate.
If an easier installation is needed, then both the ignition and the voltage sense wire can be wired to a permanent feed. With this method the outputs would activate once the battery voltage rises above 13.5v. They would not de-activate until the battery voltage drops back below 13.5v (this could be 30secs to a few minutes dependent on the condition of battery and charging system)
To make the unit even more useful it has outputs that are both active and inactive when the engine is running. This means we can not only control what we can turn ON when the engine is running, but we can also inhibit circuits so they can’t be turned on when the engine is running.
As in the video we have wired the common module input to the ignition live, and used the 2 outputs to control a heated screen relay, and a starter relay. When the ignition is turned on the non running output sends an ignition positive to the starter relay allowing the vehicle to be cranked. Once the engine is running the module would drop the non running output, and send the ignition output to the screen relay. Now the heated screen can be turned on, and the starter can’t be accidentally activated.