Definition: car memory saver
A small battery that is connected to a car's 12 volt socket or OBD port while the battery is being replaced. The memory saver applies just enough voltage and current to keep data in RAM alive until the new battery is installed. The "keep alive" memory" in the car is data collected during the vehicle's operation to keep everything running smoothly.
Otherwise It Takes Multiple Starts
If a battery is replaced without using a memory saver, the car has to be started about 10 times for at least 15 minutes to restore the settings it had before. Drivers should notice smoother performance each time they restart their car.