It doesn't need battery power. Instead. it uses solar energy to charge itself. Just put it under the sun. The solar panel of the flame light collects the amount of solar energy during the day. and automatically turns on the lighting mode at night. which makes it pleasant lights. It will work for long time .it comes with a built-in Li-ion Battery(1500mAh). Light up 10 hours in summer and 5 hours in winter after fully charged. It is resistant to all weather conditions throughout the year. including hot summers. snowy winters and heavy rains. It is 100% waterproof. so you don't have to worry about even heavy rain.