SCP boards for fit-and-forget light-powered products that can recharge themselves. Existing products can be modified by removing batteries and plugging in an SCP to create a self-powered, no maintenance device.  http://www.saelig.com/sol-chip/sol-chip-pak.htm

The patented Sol Chip Pak™ (SCP-R2801) Power Modules offer 24/7 non-stop functionality by combining state-of-the-art solar cells, a rechargeable battery, and advanced power management circuitry. These power modules include all the components that are required to harvest energy from ambient light, charge a built-in rechargeable battery, and deliver a stable voltage to a load. Sol Chip’s patented technology integrates solar energy conversion with very large scale integration (VLSI) techniques to produce unique ambient light harvesting devices that can even extract energy from office lighting to provide constant power. These versatile boards, based on Sol Chip’s unique Saturn cells, provide power even in office light conditions.

The output voltage of these "everlasting solar batteries” is regulated to 3.6V, but other voltages are available by request to suit alternate applications. Versions are available with 1, 2, 3, or 6 Saturn solar cells depending on the power needs. The 6-cell version provides an average output current of up to 750uA from the integrated solar cells, with up to 1.5A peak current. The capacity of the 3.6V onboard rechargeable batteries in the series is 190 - 1100mAh.