GPS Power Saving
Edit on GitHubThe NEO-6M power modes, what the beacon's GPS power setting changes, and the battery trade-offs.
GPS Power Saving
The GPS module can draw more current than the radio when left to its own devices. Power management for the GPS is a real decision, not an afterthought.
Current draw by state
| State | NEO-6M draw |
|---|---|
| Acquiring (searching for satellites) | 40 - 60 mA |
| Tracking (fix locked) | 25 - 40 mA |
| Standby (module asleep) | 10 - 20 mA |
| Power off | 0 mA |
At 30 mA average, a GPS left running for 24 hours consumes roughly 0.7 Ah: about two-thirds of a typical 18650 cell. That is the whole battery budget for nothing but positioning.
The beacon’s options
| Setting | Behavior | Battery cost |
|---|---|---|
| GPS off | Module unpowered, no coordinates | Zero |
| GPS on, sleep with device | Module unpowered during deep sleep, cold start per wake | Medium, short bursts |
| GPS always on | Module tracks continuously, hot starts | High, continuous |
The honest middle ground
For a rescue beacon that must transmit a position, the recommended configuration is: GPS always powered while beaconing, so the payload always carries a current fix, and accept the battery cost. The beacon was designed for 65+ hours in this configuration (see Power Budget and Runtimes).
Disabling GPS entirely
If you run without a GPS module, set the feature off. The beacon then transmits the manual coordinates you enter in CONFIG mode, which is the correct approach for a fixed or semi-fixed installation.
Related pages
- Power Budget and Runtimes for the numbers
- Firmware Deep Sleep for the sleep integration
- GPS Warm vs Cold Start for the acquisition cost