The Hawk can be powered in a variety of different ways to suit various applications.
1. Powered by only the internal battery
The Hawk has a 3500mAh internal rechargeable Li-Po battery.
Battery life estimates, while invaluable, are difficult to generalize for the Hawk.
This is because the battery life is dependent on which sensors are connected to the Hawk, as well as the sampling frequency for the specific application.
For details, please see Hawk-Battery Life Estimates
2. Connected to an external power source (with internal battery enabled)
Another power option for the Hawk is connecting the external power terminals (Vin and GND) to an external power source.
The input voltage should be 6-28V. Recommended 12V or higher.
The external power source could be mains power or a source like a solar panel.
This external power can be used to power the device and keep the internal battery charged. The internal battery can serve as a backup in case the external power drops below the minimum required voltage (e.g. a solar panel at night).
The Hawk has specific FW smarts to deal with "brownout" events. If a device browns out, the "battery good" digital input flag will be cleared. When external power is detected, the "power unstable" flag will be cleared. Then when the battery level recovers once more, the "battery good" flag will be set again.
For solar panel details, please see Connect a solar panel to the Hawk.
Here is an example of a mains power adapter that could be modified for use with the Hawk: Adapter
3. External Battery Pack (with internal battery disabled)
An external battery pack can be connected to the same pins as described above.
This allows the Hawk to be deployed for extremely long periods of time in remote locations where solar panels may not be appropriate.
When an external battery pack is connected, the internal battery charging circuit should be disabled.
If not disabled, the internal battery charging circuit will draw extra current from the external battery.
With the internal charging circuit disabled, the passive current draw is much less (~30uA compared to ~200uA)
Disabling the internal battery charging circuit will increase the life of the external battery.
The internal battery charging circuit can be disabled in Device Manager (See below)