The main unit and battery are practically unused, having only been used a few times. This is a custom item with a 5000mAh (HIDISC brand) battery attached. By "custom," I only mean that the battery is secured and connected with a cable, so there's nothing dangerous. It can be charged via USB while attached. I haven't tested how long it can be used, but it seems like it can be used for a considerable amount of time. I used it on high for about 30 minutes, and the battery only decreased by 10%. Simple calculation suggests it can be used on high for over 300 minutes. With the power consumption of this device, a 5000mAh battery is not something usually equipped. The weight wasn't bothersome either. #THANKO #NeckCooler #Peltier