====== Power consumption ======
Voltage 12.4
  * 40mA  - Device off - charging fully discharged battery
  * 10mA  - Device off - charged battery after few hours - constant voltage mode @4,2V
  * 28mA  - Device on  - minimum noticed value
  * 32mA  - Device on  - average consumption when active and registered to network
  * 124mA - Device on  - maximum noticed value after startup.
  * 100mA - Device on  - receiving calls, responding with SMS

Assuming 50mA consumption, it gets 1.2Ah per day, 8,4Ah per week.

Minimum usable voltage is 7V (current consumption is on normal level). 
Below this voltage current consumption drops proportionally.

  * 5.3V current consumption is ~10mA. No power cut alert received.
  * 4.1V power cut message received. Internal DC-DC convert XL1509-ADJE1 has //"Wide 4.5V to 40V Input Voltage Range"//

====== Internal battery test ======
Reporting every 30 seconds using GPRS and TCP
  * started 14:53 (893 min
  * last report 19:06 (1146 min)
Online for 253 minutes = 4h 13 min - very good result!