Most solar lights use rechargeable batteries, but some models can also be used with regular alkaline batteries as a backup. There are some important things to keep in mind if you choose to use regular AA batteries in your solar lights. Make sure that the batteries are fresh, as older batteries may not hold a charge as well. You should also check the manufacturer's instructions to see if using regular AA batteries will void the warranty on your solar lights. Keep in mind that using regular AA batteries should not be used as a permanent solution, as they will not last as long as rechargeable batteries. Use them only as a backup in case of an emergency or power outage.