The logistics and industrial sectors increasingly depend on Internet of Things (IoT) trackers to keep goods visible and regulated across long supply chains. Yet one of the most persistent challenges is ensuring that these trackers operate continuously for years without maintenance. Many projects fail because the devices burn through their batteries after a few months. This article explains the engineering principles behind multi‑year battery‑powered trackers, drawing on low‑power design practices and evidence‑grade sensing to make your devices last and provide reliable data.
Why battery life matters
According to logistics industry reports, 10‑40 % of supply chain assets ‘disappear’ each year. When asset‑visibility devices stop working due to a depleted battery, an expensive container can vanish into a black hole, leaving insurance claims, regulatory penalties and lost revenue. Long battery life also reduces field service visits and environmental impact: every unnecessary battery replacement generates waste and emissions.
For a detailed case study of a long‑life asset tracker in the field, see our article on the GPT12‑X 4G tracker which explains how a palm‑sized LTE‑M/NB‑IoT device can quietly ping home for years without human intervention.
Understanding power consumption
Battery life is dictated by how often and how long each subsystem (sensors, communications, processor) stays awake. Two key low‑power modes introduced by the 3GPP standards have made large strides in extending device life:
- Power Save Mode (PSM). After a transmission, the modem can enter a deep sleep where it wakes only to send data or listen briefly for network pages. A Telit whitepaper notes that a Cat‑M1 device transmitting once per day and using full PSM can last well over ten years on two AA batteries. PSM drastically reduces standby current by decoupling network registration from data sending.
- Extended Discontinuous Reception (eDRX). This mechanism lengthens the time between the network’s paging cycles so the device can sleep longer. It is ideal for devices that require network‑initiated communication. The same paper explains that combining eDRX with deep sleep cycles can support multi‑year battery life in harsh field conditions.
These modes hinge on firmware and network configuration: you must program your modem to stay in sleep as long as possible and avoid unnecessary network interactions.
Duty‑cycled operation
Texas Instruments notes that wireless battery‑powered devices must use a duty‑cycled approach: power up, take a measurement, transmit data, then go back to sleep. This simple cycle ensures that sensors and processors are active only when needed. A reference design from TI demonstrates that efficient buck converters and low‑power modes can deliver over ten years of life on a coin‑cell battery. When designing your tracker, adopt this rhythm:
- Wake up on schedule or event. Use a real‑time clock or motion/temperature threshold to wake the microcontroller.
- Collect measurements quickly. Read from accelerometers, temperature sensors and any other needed peripherals with optimized sampling rates.
- Transmit concise data. Use efficient encoding to send only the essential bytes; compress or summarise when possible.
- Return to sleep. Disable all clocks and place the MCU and radio in their lowest consumption states.
The shorter this sequence and the less often it runs, the longer your battery will last.
Sensor design for evidence‑grade data
Battery optimization must not come at the expense of data integrity. Evidence‑grade tracking means that your device produces timestamps and sensor readings that stand up in a court of law or withstand regulatory scrutiny. Use high‑quality sensors and calibrate them meticulously:
- Accelerometers and gyroscopes detect shocks and tilts that indicate mishandling or drops. Sampling at higher rates (e.g. 1 kHz) during an event but sleeping otherwise can capture sudden events without constant power draw.
- Temperature and humidity sensors ensure goods stay within safety ranges. Choose sensors with low drift and stable references; calibrate them against known standards.
- Light and magnetic sensors can detect unauthorized openings of containers or tampering.
Calibration should be performed during manufacturing and periodically in the field. Use on‑board self‑test routines to detect sensor drift and trigger recalibration alerts. Properly timestamp and sign all sensor data to provide an audit trail.
Choosing connectivity: NB‑IoT vs LTE‑M
Selecting the right radio technology balances coverage, bandwidth and battery life. Two low‑power wide‑area network (LPWAN) standards are predominant:
- NB‑IoT operates on narrowband (180 kHz) and offers excellent penetration into buildings and underground. Devices typically last ten years on a battery because NB‑IoT uses less power and has longer sleep cycles. NB‑IoT is ideal for sensors that transmit small packets infrequently and do not require mobility.
- LTE‑M (Cat‑M1) supports higher data rates (up to 1.4 MHz bandwidth) and voice and mobility, allowing trackers to roam across countries and connect on moving vehicles. LTE‑M devices can still achieve 5–10 years battery life with proper PSM/eDRX configuration, making it suitable for real‑time asset tracking with firmware updates.
Hybrid devices that support both NB‑IoT and LTE‑M can switch modes depending on network availability, balancing power and coverage. Use roaming SIMs to ensure access to multiple operators, and implement fallback logic to avoid connection loops that drain the battery.
Power management techniques
Beyond choosing a radio and enabling low‑power modes, you can further extend battery life through hardware and firmware optimizations:
- Component selection. Choose microcontrollers with sub‑µA sleep currents and radios with integrated power amplifiers. Lower I/O leakages and high‑efficiency voltage regulators minimize quiescent drain. Keysight engineers emphasize that carefully optimizing sensor design allows devices to run a coin cell battery for at least ten years.
- Power domain control. Partition your circuit into domains and switch off entire blocks (e.g. sensors, GNSS module) when not needed. Use load switches or DC/DC converters with enable pins.
- Event‑driven firmware. Avoid polling loops; instead use interrupts (from timers, sensors, or the modem) to wake the MCU only when there is work to do.
- Energy harvesting. Solar, vibration or thermal energy can recharge batteries or supercapacitors. While this adds cost, it offers semi‑permanent operation.
- Data compression and edge analytics. Process data locally to reduce transmission length and frequency. For example, send a daily summary rather than every raw sample.
Designing for reliability and sustainability
Long‑life trackers must survive harsh conditions and maintain data integrity for years. Consider the following:
- Rugged enclosures. Protect electronics against moisture, dust and vibration. Use conformal coatings and potting compounds for extreme environments.
- Industrial temperature‑grade components. Ensure the battery and electronics operate from −40 °C to +85 °C, covering cold chains and desert shipping routes.
- Firmware update mechanism. Implement over‑the‑air updates with secure bootloaders. Even rarely, you will need to patch security vulnerabilities or calibrate sensors.
- End‑of‑life recycling. Use recyclable materials and design for easy disassembly. Multi‑year devices reduce waste, but eventual recycling remains important.
Steps to implement a multi‑year tracker
- Define your sensing and reporting requirements: How often do you need data? What conditions are you monitoring? Resist the temptation to collect everything; focus on actionable signals.
- Model your power budget: Estimate the energy consumed by each subsystem in active and sleep modes. Use spreadsheets or simulation tools to calculate battery life under different duty cycles.
- Prototype with instrumentation: Build prototypes and measure current consumption with high‑resolution tools. Identify unexpected drains (e.g. pull‑ups, unsealed debug pins, or firmware bugs).
- Test under real conditions: Deploy units in the environments they will face: warehouses, trucks, cold storage and ships. Log battery voltage and sensor accuracy over time.
- Iterate and optimise: Adjust sleep durations, sensor sampling rates and transmit intervals based on test results. Small adjustments can double lifetime.
- Plan for compliance and certification: Ensure radio modules meet local regulations (PTCRB, GCF) and that data handling complies with privacy laws (GDPR, HIPAA).
Conclusion
Designing a battery‑powered IoT tracker that lasts multiple years is a multidisciplinary engineering effort. By leveraging low‑power modes like PSM and eDRX, optimising sensor operations and carefully managing power domains, you can build devices that deliver reliable, evidence‑grade data for a decade or more. These practices reduce total cost of ownership and support sustainability goals by minimising field service and waste. As supply chains become more complex and regulatory demands increase, long‑life trackers will be essential for maintaining visibility and trust.
For more operational guidance on managing fleets of long‑life trackers and choosing the right duty‑cycle modes for your business, explore our operational playbooks for long‑life LTE‑M/NB‑IoT trackers.
Frequently asked questions
Q: How long can NB‑IoT and LTE‑M devices last on a battery?
A: NB‑IoT devices often achieve up to ten years of battery life because they use narrowband channels and support long sleep cycles. LTE‑M devices can last 5–10 years with proper power‑saving features like PSM and eDRX.
Q: What is the difference between PSM and eDRX?
A: PSM allows a device to turn off its radio and network registration completely between transmissions, waking only to send data. eDRX extends the interval during which the network expects the device to listen for pages, enabling longer sleep but still supporting network‑initiated communication.
Q: Can energy harvesting replace batteries?
A: Energy harvesting (solar, vibration, thermal) can supplement or recharge batteries but often cannot supply enough continuous power for cellular radios. However, it can significantly extend battery life and, combined with low‑power design, may support semi‑permanent operation.
Q: What steps ensure data is evidence‑grade?
A: Use high‑quality sensors, calibrate them regularly, timestamp and digitally sign data, and maintain a secure audit trail. Evidence‑grade data must be traceable and tamper‑evident.