The external battery, GP Batteries 381, is a universal charging device with a charging capacity of 8400mAh that ensures fast charging of your mobile devices while on the go. The battery's large storage capacity allows for multiple charging of smartphones, and with its compact body size, the battery is incredibly portable and can be taken anywhere. It comes with 2 USB outputs that have a high current max range of 2.4 and 2.1A. The LED indicators display current battery charge status and when it needs to be recharged the Li-ion battery can be charged directly from the USB port on your computer or USB charger using the included USB cable.
Smartphones, cell phones, MP3, MP4, iPod, GPS navigation
The capacity of the built-in battery:
Max. 2000 mA/5V DC
Charging pin PSU: 1x micro USB 2.0
Dual 1 × 2400 mA/5 V DC + 1 × 2 100 mA/5 V DC
Connector for charging the connected device: 2 x USB 2.0
0 to +40°C
Displays charging progress
Displays the battery status
Short-circuit protection, overload protection, discharge protection, overcharge protection
1 x USB cable micro-USB 2.0
Dimensions (height x length x width):
107 × 73 × 23mm
The actual (physical) capacity of the battery cell is 8400mAh. Practically, however, there can not be any external energy loss for there to be a transfer of the equivalent power to the mobile device's battery. There is normally a loss of energy that arises from a drive voltage of 3.7V transferring to 5V. Also, with any power transition with contact resistance, there is less than 100% efficiency when storing energy in the receiving device's battery, due to temperature conditions, higher charging current and the like. Generally, constant power can move from the external battery to the charging device's cell with an efficiency between approx. 85 to 70% depending on conditions.