Patent ID: 8026630

Claim:
A system for supplying voltage to electrical loads in an onboard electrical system of a motor vehicle, the system comprising: a first onboard electrical system region of the onboard electrical system, the first region having an electric generator, a vehicle battery, and one or more first electrical loads; a second onboard electrical system region of the onboard electrical system, the second region including a supercap and one or more second electrical loads; a current blocking device operatively configured between the first and second regions, the current blocking device permitting a current flow from the first region into the second region and largely preventing a reverse current flow from the second region into the first region; and a separate control/power unit for controlling at least one of precharging and coupling/decoupling of the supercap with respect to the onboard electrical system; wherein an output voltage of the electric generator is increased and the supercap is charged when a first threshold value of an electrical voltage in the second region is undershot, wherein the separate control/power unit is operatively configured to diagnose the supercap by performing a capacitance and/or resistance determination during the precharging of the supercap.