The battery is better, the charging will be because the battery is not enough, there will be problems in emergency, if you charge it in time or bring your own power back to the pool. In general, the transmission power of the dry battery is a little larger, generally about 20 meters, and the charging is generally about 15 meters. Or according to their own needs to set, if you are in the speech or to customers to introduce products, etc., use the charge is better, if it is to give a lecture to students need to interact with students, use the battery is better.