Is there a battery jump starter?

Yes, there is a battery jump starter. It's a device used to start a vehicle that has a dead battery. It consists of a portable power source, typically a high-capacity 12-volt battery, and a set of jumper cables. The power source provides the necessary electrical current to start the vehicle, and the jumper cables are used to connect the jump starter's battery to the vehicle's battery. Once connected, the jump starter provides a temporary power supply to the vehicle's electrical system, allowing it to start. Battery jump starters are commonly used to provide assistance in emergencies when a vehicle's battery fails.