NOVELTY - A three-position switching device (300) can be operated in at least two states to selectively electrically connect at least one positive terminal (310) to a first positive output (110) or a second positive output (210). A main battery (100) and an auxiliary battery (200) do not simultaneously supply electrical energy to an electrical system when the positive terminal and a negative terminal (320) are electrically coupled to the electrical system.    USE - Multiple battery system for supplying electrical energy to electrical system of vehicle e.g. electric vehicle, hybrid vehicle.    ADVANTAGE - Enables reliable supplying of electrical energy to electrical system. Eliminates the need to jump-start a vehicle or, if the electrical system has failed, allows the user to determine such a failure and try to reach some assistance while operating from the auxiliary battery. Eliminates the danger of trying to jump-start an automobile, where there is the potential for electrical sparking and explosion. Avoids the need for a jump-start, thus both safety and security are improved, as there is no need to leave your vehicle to seek assistance or flag down strangers when the vehicle will not start. Shortens time to charge the batteries, and allows a user to quickly start his or her vehicle and immediately begin recharging both the main and auxiliary batteries. Can be universally installed in place of existing battery. Provides sufficient reserve electrical power for most, if not all, situations, even in worst-case type discharge scenarios, such as failure in the electrical system. Provides auxiliary power easily and virtually instantaneously. Provides simple structure which does not require costly structures or modifications to existing electrical systems, circuitry, or other components. Can be cost effectively manufactured and used. Facilitates efficient utilization of available space within existing battery housing dimensions such that the main battery exceeds minimum cold cranking amperage (CCA) output ratings for most original equipment manufacturer (OEM) vehicles.    DESCRIPTION OF DRAWING(S) - The drawing shows the perspective view of multiple battery system.    Main battery (100)    First positive output (110)    Auxiliary battery (200)    Second positive output (210)    Three-position switching device (300)    Positive terminal (310)    Negative terminal. (320)