Curable thermoset resin compositions are described which are useful for imparting water andor solvent resistance to gel coated fiber-reinforced polymers. The predistortion architecture is based on the stored-compensation or memory-compensation principle by using a combined time-delay addressing method, and therefore, the architecture has an intrinsic, self-calibrating time-delay compensation function. Balloon cone and waist thicknesses are reduced by varying the axial tension and blowing pressure at several stages as a mold containing the balloon preform is dipped into a heating medium. The inserts are replaceable, and the spacing of the cutting head and anvil edge is variable to optimize the shearing action. The embodiments further describe a power cell system including a number of power cells, a frame for supporting the power cells, and electric connections, in particular, a busbar arrangement for connecting to the power cell.