Onboard electrical system for a vehicle, having the following features: - a first current path, comprising: • a system load having at least one current consumer, • a first energy store for supplying electric power, • a first controllable switch, which, in a closed switching state, electrically connects the system load to the first energy store, - a second current path, comprising: • the system load, • the first and a second energy store for supplying electric power, • a second controllable switch, which, in a closed switching state, electrically connects the system load to the first and the second energy store, - a control apparatus having • a monitoring unit (ÜE) for determining an onboard electrical system voltage as a first onboard electrical system parameter value (V_BN) and for comparing the presently determined first onboard electrical system parameter value (V_BN) with a first prescribed threshold value, • a first control unit for closing the second switch or keeping the second switch in a closed switching state, respectively, depending on the presently determined first onboard electrical system parameter value (V_BN) in comparison with the first threshold value, characterized in that the first control unit is further embodied to actuate the first and second switches simultaneously and in opposition to one another by using one and the same first control signal. - a first current path, comprising: • a system load having at least one current consumer, • a first energy store for supplying electric power, • a first controllable switch, which, in a closed switching state, electrically connects the system load to the first energy store, • a system load having at least one current consumer, • a first energy store for supplying electric power, • a first controllable switch, which, in a closed switching state, electrically connects the system load to the first energy store, - a second current path, comprising: • the system load, • the first and a second energy store for supplying electric power, • a second controllable switch, which, in a closed switching state, electrically connects the system load to the first and the second energy store, • the system load, • the first and a second energy store for supplying electric power, • a second controllable switch, which, in a closed switching state, electrically connects the system load to the first and the second energy store, - a control apparatus having • a monitoring unit (ÜE) for determining an onboard electrical system voltage as a first onboard electrical system parameter value (V_BN) and for comparing the presently determined first onboard electrical system parameter value (V_BN) with a first prescribed threshold value, • a first control unit for closing the second switch or keeping the second switch in a closed switching state, respectively, depending on the presently determined first onboard electrical system parameter value (V_BN) in comparison with the first threshold value, • a monitoring unit (ÜE) for determining an onboard electrical system voltage as a first onboard electrical system parameter value (V_BN) and for comparing the presently determined first onboard electrical system parameter value (V_BN) with a first prescribed threshold value, • a first control unit for closing the second switch or keeping the second switch in a closed switching state, respectively, depending on the presently determined first onboard electrical system parameter value (V_BN) in comparison with the first threshold value,