A novel approach for determining an amount to be billed to a customer for the use of resources is based upon usage data and value data. The solar array has a plurality of solar modules, each module having at least one DCDC converter for converting the raw panel output to an optimized high voltage, low current output. According to another embodiment, the markings and numbers on the convex surface are the same as the markings and numbers on the concave surface. The Vref memory is configured to store respective Vref values mapped to respective groups of cells.