I have a friend who used his solar lights inside at night when his current was off during a bad storm. He stuck them in a jar or bottle and said they gave off plenty of 'free light'. He put one in each room and would put them back outside in the daytime and bring them in at night as long as the current was off. They are safe to use and cheaper than batteries. Bring in a solar light one night and test it.
Due to a thunderstorm, they lost power for about 5 hours. They were scrambling around in the darkness, looking for matches, candles, flashlights, etc. They looked outside, and noticed their solar lights shining brightly all around their patio, stairs, dock, etc. They were beautiful. His wife walked outside, and brought several of the solar lights inside.
They stuck the solar light pipes into plastic drink bottles containers and they made the nicest, brightest, safest, lighting you could ever imagine.
They put one in the bathroom, the kitchen, the living room, etc. There was plenty of light. There are all types of solar lights available. They bought theirs at Harbor Freight. They had put them all around their yard. They look nice and they do not attract flying bugs like the outdoor lights around their doorway.
The lights they have fit into the small (20 oz) water bottles and they also fit into most of the larger liter bottles. If you need a weight in the plastic bottle to keep them from tipping over, you can put a few of the pretty colorful "flat marbles" that they put in aquariums, and vases. (you can also use sand, aquarium gravel, etc., whatever you have available).
The lights they have were perfect inside their home. They burn all night long if you need them.
The next day, you just take your solar lights back outside and they will instantly recharge and be ready for you to use again any time you need them.
Perfect for power outages, storms, hurricanes, etc.