Battery charging controller

Abstract

A controller for a solar electric generator that permits the generator to produce power substantially at its maximum capacity while also providing efficient charging at three charging stages; i.e., bulk charging, acceptance charging and float charging. Power is transferred from the generator to a temporary electric storage device that is periodically partially drained of power to maintain the temporary electric storage device at a voltage corresponding to the voltage needed by the generator to provide maximum generator power. The electric power drained from the temporary storage device is used to charge conventional batteries. In a preferred embodiment, the temporary storage device is a capacitor that is part of a buck regulator operating at 50 kHz with duty factor control between 0% and 100%. This buck topology switching type regulator provides the periodic draining. In the preferred embodiment control of the duty factor of the buck regulator is utilized to limit current, to prevent battery over charging, to test for the voltage corresponding to maximum power, and to operate the solar generator at is maximum power voltage. When operated at its maximum power operating point, the output to the battery is constant power, providing greater battery charge current than prior art controllers. Additional controls are provided to adjust battery charge voltage to permit maximum current flow during bulk charging, and at a first pre-selected charge voltage during acceptance charging and at a second pre-selected charge voltage during float charge. In a preferred embodiment provision is made for periodic equalization overcharging to improve battery performance and lifetime.

Dependencies are inferred from the claim text.