OpenTracker is 100% open source so any power option can be enabled and disabled as you wish, to keep the power consumption under control.
Using the default firmware, there are the values:
- Low-Power mode: 35mA
- Low-Power mode with USB disabled: 25mA
- Standard mode - active: 55mA
- Transmission burst: 250mA
The power save and debug options can be enabled via SMS, but you can also modify the code to disable any hardware part you do not need to cut the power consumption.