An implantable device having a power source is provided. The power source uses reverse electrowetting technology to generate a charge to power the implantable device. The power source includes a flexible, non-conductive substrate having a first side and a second side opposite the first side with a channel between the first and second sides. Electrodes are arranged about the channel in a predefined pattern. A liquid is contained in the channel. The liquid includes a dielectric liquid and a conductive liquid that do not mix. The electric change is generated by moving the liquid back and forth across the electrodes. The force to pump or move the liquid is provided by organic means, such as, for example, the change in blood pressure between systolic and diastolic, the expansion and contraction of an organ, or the movement of a muscle.