I ran a battery capacity test. System was configured to stay in sleep and wake up every 10 minutes. Then try to get a GPS fix and transmit an uplink. Then tested this in two scenarios, shown in the following plot.
On the left, a GPS fix is easily obtained and power draw is small. For the middle section the GPS cannot get a fix and it keeps trying for 10 minutes. During this phase 62% of the battery capacity is lost in 8.7 hours.
But something does not add up. With this power profile I expect 14h of run time. Further tests needed. Possible causes:
- Lower than advertised battery capacity at 0.1C discharge rate
- I'm measuring battery voltage wrong
- I'm using a voltage-to-charge LUT that's not appropriate for the battery