A system and method for extracting power from a power source having a high internal resistance are presented. A capacitor is connected to the power source. A switch is configured to selectively connect and disconnect the capacitor from a load. A processor is configured to monitor an energy flow from the power source into the capacitor and an amount of energy in the capacitor. When the energy flow from the power source into the capacitor falls below a first threshold, the processor is configured to close the switch to dissipate energy from the capacitor to the load. When the energy in the capacitor falls below a second threshold, the processor is configured to open the switch to disconnect the capacitor from the load.