There are several schematic examples for various energy sources and energy storage elements in the bq25504 data sheet. In this example, a solar energy source, it can be seen how few external components are needed for bq25504 energy harvesting solutions. On the top middle of the schematic, connected to pin 14, is the energy storage element. The flexible architecture and user settings allow various types of energy storage elements, including rechargeable batteries, super-capacitors, thin film batteries, capacitors, and other types of elements. The capacitor, Cstor, connected to pin 15 and the energy storage element, plays an important role in the operation of the bq25504 in it’s boost operation, load buffering, and cold-start operations.