In the "Small Cooling Fan" in a built-in lithium battery approach is indeed very fresh. Currently popular online a built-in lithium battery electric fan, the seller said that in the case of full power, after power failure "Small Cooling Fan" can continue normally blow 15 hours. In fact, this built-in battery is designed to prevent blackouts, but for consumers, the built-in lithium battery fan can have more uses: for example the "Small Cooling Fan" inconvenient to plug the power cord to move on the balcony, or driving out to do when unplugged from the fan takes on, 15 hours of battery life is sufficient to meet people's needs for outdoor use.