LoRaWAN Battery Monitoring: Why Normal Voltage Can Still Lead to Device Resets

A remote sensor reports a normal battery voltage. Later, it stops sending data. When a technician checks it again, the voltage still appears acceptable.

The problem may occur only when the device wakes up, powers a sensor or starts transmitting.

LoRaWAN battery monitoring should consider the battery’s behavior during actual operation. A voltage reading taken while the device is resting cannot, by itself, establish whether the power system can support its next workload.

For livestock trackers, farm sensors and remote industrial terminals, better battery diagnostics can help teams investigate intermittent resets and plan field maintenance.

What Should LoRaWAN Battery Monitoring Measure?

A useful monitoring design separates several measurements.

These values should be interpreted together.

A reading taken before transmission and another taken during transmission describe different conditions. Labeling both simply as “battery voltage” can hide useful information.

Why Can Voltage Drop During Transmission?

A battery-powered device spends much of its time sleeping, then briefly draws more current when it performs work.

The battery, contacts, wiring and power circuit must support that demand while keeping the supply above the device’s operating limits.

Battery manufacturer Saft notes that voltage falling below a device’s cutoff level during current pulses can cause a reboot. Its guidance also emphasizes matching the battery to the application’s load profile.

For a LoRaWAN terminal, investigate the complete power path:

• The selected battery and its pulse capability.
• Battery age and storage history.
• Contact resistance and connector condition.
• Regulator behavior.
• The timing of sensor, GNSS and radio operation.
• Available energy storage in the power circuit.

Changing the reporting interval alone may not resolve a power interruption that occurs during each individual transmission.

Temperature Changes the Meaning of a Voltage Reading

Outdoor devices can operate under very different conditions across the year.

A sensor tested inside an office may behave differently during a cold morning at a remote farm. Saft’s cold-environment metering case study describes low-temperature voltage effects and the importance of selecting a battery solution for the actual application.

Record temperature alongside battery measurements where practical. Specify whether the value comes from the battery, circuit board or enclosure; an enclosure reading may differ from the battery’s temperature.

Compare readings collected under similar conditions before concluding that a voltage change represents battery depletion.

Consider Passivation for Relevant Battery Chemistries

Some remote sensors use primary lithium-thionyl chloride batteries.

For these batteries, passivation can affect the initial voltage response when a load is applied. Saft explains that the passivation layer can increase internal resistance and produce an initial voltage delay under load. The significance depends on the battery and application.

This does not mean every device that stops reporting has a passivation problem.

It means that battery selection should account for storage, temperature, sleep duration, pulse demand and the device’s cutoff voltage. Review the operating profile with the battery supplier rather than diagnosing the cause from a single remote reading.

Do Not Convert Voltage Directly into a Universal Battery Percentage

A simple linear conversion from voltage to percentage can create misleading precision.

Different battery chemistries have different discharge behavior. Temperature and measurement load also affect the observed voltage.

If a platform displays remaining battery percentage, define how the estimate is produced and what evidence supports it.

For some projects, maintenance states may be more useful than a percentage:

These are proposed application states, not mandatory LoRaWAN status categories.

Design Measurements Around the Device’s Work Cycle

Define a repeatable measurement sequence during firmware development.

For example:

1. Wake from sleep.
2. Record voltage and temperature under a defined condition.
3. Activate the required sensor or GNSS receiver.
4. Capture supply behavior during the relevant workload.
5. Record diagnostic results.
6. Transmit the available measurements.
7. Return to sleep.

The measurement hardware must be able to capture the event of interest. A slow reading taken after a short voltage dip may miss the actual minimum.

Also define when results become available. Diagnostics captured during one transmission may need to be stored and included in a later uplink. If a reset interrupts the operation, preserving the reset reason or fault record can be particularly useful.

Keep Diagnostic Payloads Focused

Battery diagnostics should fit the application’s communication and energy budget.

A compact payload could include:

• Voltage measured under a defined condition.
• Minimum voltage captured during the previous monitored operation.
• Temperature.
• Restart counter.
• Reset-reason code.
• Power-warning flags.

Document units, scaling, signed values, unavailable-value codes and firmware compatibility.

For a livestock GPS collar, consider separating GNSS-related power behavior from radio-related behavior. A generic “low battery” flag may not show which operation caused the problem.

These fields require appropriate hardware and firmware support; they should be agreed during development.

Validate the Complete Power System

A useful pilot should test more than a fresh battery at room temperature.

Include representative conditions such as:

Use suitable instruments to observe short supply interruptions. Compare bench results with the diagnostic values reported by the device.

Define acceptance criteria around successful operation, supply limits and maintenance requirements. Avoid applying one voltage threshold to every battery chemistry and hardware design.

OEM LoRaWAN Battery Monitoring Development

Battery diagnostics are most effective when included early in hardware and firmware design.

Projects may require voltage-measurement circuits, temperature sensing, reset diagnostics, persistent counters and a documented payload format.

Shenzhen Jinshengchang Technology Co., Ltd. provides a custom LoRaWAN PCB design and development service. Battery-monitoring requirements can be included in the project review, with the final implementation agreed for the selected hardware.

When discussing a project, provide the battery type, installation environment, reporting schedule, sensor workload, intended service interval and maintenance constraints.

Frequently Asked Questions

Can normal battery voltage rule out a power problem?

No. A resting measurement may not reveal a brief voltage drop during a higher-current operation.

Does a missing LoRaWAN uplink prove that the battery is empty?

No. Missing data can also involve coverage, gateway connectivity, device configuration or other faults. Battery diagnostics provide additional evidence.

Should every packet include all battery measurements?

Not necessarily. Use a reporting schedule suited to the maintenance requirement, and consider additional diagnostics when a warning condition occurs.

Can adding a capacitor solve every voltage-drop problem?

No. Energy-storage components must be selected as part of the complete power design. Battery capability, temperature, leakage, recharge time and component limits still need evaluation.

Plan Battery Maintenance with Better Evidence

Effective LoRaWAN battery monitoring connects the voltage reading to the conditions in which it was measured.

Combine defined measurements, temperature, operating history and reset diagnostics. Validate those records against the device’s actual workload so the platform can give maintenance teams useful evidence before the next field visit.