Abstract: A rechargeable battery having a photovoltaic device and battery charging circuitry integral therewith. A rechargeable battery such as, for example, a Lithium battery, includes a current regulating circuit interposed between a photovoltaic device mounted on an outer surface of the battery and the terminals of the battery. In order to attain maximum power transfer between the photovoltaic device and the battery, the circuit includes a feed-forward feature that regulates the current flow from the photovoltaic cell to the battery in response to changes in the voltage output of the cell. When the voltage output (V) of the photovoltaic cell drops below a predetermined value, the current (I) flowing from the cell to the battery is decreased in accordance with the equation V=aI+b, where the coefficients a and b are constants having a value depending on the type of rechargeable battery employed.

Abstract: A case or holster for the storage and transport of a cellular phone or similar battery powered communication device. The holster is adapted to be attached to and worn upon a person's body. The holster includes at least one photovoltaic element and circuitry that, in combination, enables solar energy to be used to charge a battery within the phone when the phone is disposed within the holster. The holster further includes a tilt-adjustable clip providing a means for tilting the holster with respect to the point of attachment of the clip to the wearer. The tiltable mount enables the orientation of the photovoltaic cell affixed to the surface of the holster to be varied with respect to the position of the sun in order to optimize the intensity of solar energy incident thereon. The holster includes a charging circuit and battery pack that is in electrical connection with the internal battery and charging circuitry of the phone when the phone is disposed within the holster.