Most dashcams plug into a usb/cig adapter and toggle on and off themselves with the power...Then most have very tiny batteries that and they can turn on and record for a minute or so to record if it senses shock...I read something on some forum (not here) that they stuck a cell phone powerbank battery in the enter console...Cable from cig lighter to the battery, another cable from the battery to the camera...Just have to find the right powerbank that's always discharging without the need to push a button...