10 - English Setup Connecting to AC power Before using your Bose Â® SoundLink Â® Mini speaker the first time, connect it to AC (mains) power and charge the battery. You can connect the power supply cord into the charging cradle, or directly into the speaker. While the battery is charging, you can begin using the speaker.
Ann is completely right. Given the alternative energy aspect of solar lights it seems a bit funny to have them charged by electrical lighting. Given enough direct and reflected sunlight in a room, they could be charged indoors. The stored charge wouldn't be as efficient as if they were in full sunlight though.
Batteries will not charge properly if the solar panel is in the shade, they rely on the energy of the sun to charge. There is another simple test you can do before replacing the solar light rechargeable batteries. Place your solar lights under direct sunshine for a day or two and see what happens. If, after this duration, the illumination time is back to normal, it means that the solar panel was not getting enough light from the sun.