Dear Nordic Team,
We are seeking assistance in resolving a significant power consumption gap observed in our nRF9151-based asset tracker. While our lab testing suggests a battery life of approximately one year, units in the field are failing much earlier.
Setup
- Hardware: nRF9151, mfw 2.0.4, 2× EVE ER34615 in parallel (38 Ah Li-SOCl₂). Note: Two pilot units include a supercap; one does not.
- Network: T-Mobile USA, LTE-M Band 12, PSM enabled (T3324=20s, T3412=60 min granted), eDRX disabled, Onomondo APN.
- Workload: GNSS uplink every 5 minutes and shadow-delta poll every 30 minutes.
- Firmware: UART and modem traces disabled for production, IPv4-only PDN.
Observations
- Lab: Average current of 4–5 mA, with an expected battery life of 1 year. sleep current is less than 40uA.
- Field (with supercap): Battery life lasted approximately 93 days across two units.
- Field (without supercap): Battery life lasted approximately 15 days on one unit, which also experienced intermittent failures.
Questions
1. Do you have any guidance on how to identify whether this discrepancy originates from the modem side or specific network behavior?
2. What is the recommended debugging approach for this issue? Should we focus our efforts on modem traces, network signaling analysis, or both?
We would appreciate any insights you can provide to help us isolate this field-vs-lab power gap.
Best regards,
Akshay