OPTIMIZE AN ENERGY STORAGE SYSTEM OF PHOTO-VOLTAIC COUPLED WITH BATTERY

A photo-voltaic (PV) battery system that includes a battery system, a photo-voltaic (PV) electricity generation system, and a charge controller. The battery system is configured to store electrical charge at a voltage Vb when fully charged. The photo-voltaic electricity generation system is configured to convert energy from incident light into electricity to thereby generate electricity. The charge controller is coupled to the battery system and the photo-voltaic electricity generation system so that at least some of the generated electricity flows through the charge controller into the battery system. For any given light intensity L within a practical solar intensity range, the electricity generated in the photo-voltaic system has a maximum power extraction voltage point Vmx(L) and its corresponding current Imx(L). They are function of the incident light intensity L. The above referred charge controller; when designed in according with the principles described in this patent disclosure can set a power extraction voltage point Vx(L) with its corresponding current Ix(L) to extract and to store an amount of energy into the above referred battery; such that this stored energy amount is larger than the stored amount would be; when it is extracted at the Vmx(L) and stored into the battery. While the (Vx(L)−Vb)/(Vmx(L)−Vb) is in between 20% and 95% for incident light intensity L within the practical solar light range. This fact and principles are described in detail in this patent disclosure.