Disadvantages of Cells in Parallel

I. They give power based on one cell, hence the brightness of light in the bulb is not high.

They do not have the same circuit path, so voltage produced by cells in parallel cannot be increased by increasing the number of cells.

In a nutshell, the electrical energy generated or transmitted through a series circuit is produced from contributions from each component (cells) whiles electrical energy from a parallel circuit is contributed by one of the components (cells).