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.
All new batteries come with different amounts of charge in them some can be completely flat so yes they would benefit from a charge in a battery charger. However do not worry if you do not have a charger just put them in the solar lights and once they get some sun they will start to charge.