The Solar-Breeze requires sufficient direct sunlight to run the paddle-wheel motors and charge the battery. However, the solar collection panels have been purposely oversized so that they are able to absorb sufficient energy to power the unit, even on lightly overcast days. On such days, however, the overall operating time of the Solar-Breeze is likely to be reduced.The Solar-Breeze’s operation on rainy and heavily overcast days will be limited to operating on battery power. Once the sun comes out, it will recharge and carry on.