The hidden OPEX of batteries, charging routines, solar assumptions, and spare devices

A Real-Time Location System (RTLS) can perform perfectly in a pilot and still disappoint six months later. The software works. Coverage looks good. Accuracy meets the requirement. Yet operations lose visibility because badges sit uncharged in lockers, a remote gateway runs low on battery earlier than expected, or nobody stocks replacements.

That is the hidden OPEX of RTLS.

Battery life matters, but the number on a datasheet is only one input. Buyers also need a power operating model: who charges devices, when batteries get replaced, how many spares stay on site, and how the system detects approaching end of life.

What Is RTLS Battery Planning?

RTLS Operational Expenditure (OPEX) goes beyond replacement cells. It includes labor, access, downtime, charging infrastructure, spare inventory, transport to remote assets, and the productivity cost of missing location data.

Start by separating four power models:

Why RTLS Battery Planning Matters for Long-Term Deployment Costs

Power model	Typical RTLS role	Main OPEX risk	Planning priority
Rechargeable	Personnel badges, wearables	Devices miss shifts	Charging ownership and turnaround
Primary battery	BLE Leuchtfeuer, long-life tags	Large replacement waves	Staggered replacement
High-capacity primary	Remote Gateways, asset Tracker	Expensive site intervention	Duty-cycle validation
Solar-assisted	Outdoor gateways, Tracker	Seasonal energy deficit	Local solar and reserve

How Duty Cycle Affects RTLS Battery Life

The first procurement question should not be “How many years does it last?” Ask: Under exactly what operating profile?

Bluetooth is a simple example. The Bluetooth SIG explicitly notes that the advertising interval involves a trade-off between power consumption and device discovery time. ⁽¹⁾ In RTLS, update speed, movement detection, transmit power, scan windows, GNSS fixes, and uplink frequency all affect the workload.

Our portfolio and experience show why test conditions matter. Its long-life Bluetooth Beacon with two 1000 mAh CR2477 cells is specified for about five years at 0 dBm and a 0.5-second advertising interval. The LoRaWAN Tracking Label uses an 1800 mAh disposable lithium battery and is specified for more than 3 years of operation with 6 GNSS reports per day. Change the assumptions and the maintenance forecast changes too.

Before approving a fleet, record:

• reporting, scanning, and advertising intervals;
• expected movement versus idle time;
• radio conditions and retransmission assumptions;
• temperature range and seasonal exposure.

How to Manage Rechargeable RTLS Badges

Wearables create visible battery OPEX because humans are part of the process.

Lansitecs LoRaWAN-Ausweis-Tracker uses a 600 mAh rechargeable Li-ion battery and supports low-battery alerts. The device has a maximum battery life of five months, but this maximum life is not guaranteed under all GNSS, Bluetooth, motion, and reporting configurations. Operations still need a charging plan.

Rechargeable batteries also age with use and storage. National Laboratory of the Rockies research notes that lifetime models consider temperature, operating windows, charge and discharge rates, storage environment, and cycling patterns. ⁽²⁾

Who owns the badge at the end of the shift? Can a supervisor see which units failed to charge? What happens when a shift starts and several badges are unavailable?

Charging capacity must match fleet size: a 40-port, 350 W USB Charge Station with 5 V output. In a 500-badge deployment, it becomes part of availability planning.

Track three pools separately:

1. In service: assigned and expected to report.
2. In turnaround: charging, cleaning, updating, or reassignment.
3. Unavailable: damaged, missing, quarantined, or under repair.

Add those pools, then add contingency stock. A hospital with round-the-clock handovers, an eight-hour factory shift, and a three-day exhibition needs different ratios.

How to Plan RTLS Battery Replacement Cycles

Primary batteries remove daily charging, but they can create another OPEX spike: hundreds or thousands of devices reaching replacement age in the same quarter.

Imagine 2,000 Leuchtfeuer installed in a single rollout. Even with a five-year forecast, maintenance planning starts on day one. Can technicians reach them easily? Will replacements arrive in time? Are battery dates and device IDs recorded?

Stagger maintenance by zone, risk class, measured battery condition, or planned shutdown window instead of waiting for mass failure. Also monitor battery telemetry and “last seen” status. A missing tag may indicate a dead device, a coverage issue, a removed asset, or a network outage.

Long battery life reduces visit frequency. It increases the importance of each visit.

Li-SOCl2 Batteries in RTLS: Benefits and Limitations

Lithium-thionyl chloride, usually written Li-SOCl2, suits many remote IoT and RTLS devices. Lansitec uses it in Produkte such as the Macro Bluetooth-Gateway, Macro Tracker, Container Tracker, and several Ultrabreitbandige Breitbandtechnologie (UWB) devices.

Der Makro-Bluetooth-Gateway uses two 19,000 mAh batteries for a 38,000 mAh configuration. As per the specs, 83 months at a five-minute report interval and 720,000 total uplink reports. The Container-Tracker uses two 4,000 mAh Li/SOCl2 batteries and lists approximately 16,000 GNSS positioning events when the report interval exceeds ten minutes, or approximately 36,000 Bluetooth positioning events.

Those figures point to the right planning method: workload first, calendar second.

Li-SOCl2 also needs chemistry awareness. Passivation helps limit self-discharge, but after storage or under certain operating conditions it can contribute to temporary voltage delay under load. Saft warns that passivation can produce low-voltage readings at startup, interfere with demanding current pulses, or trigger misleading low-battery behavior. ⁽³⁾ Buyers need not become electrochemists. They should validate pulse profile, storage conditions, temperature, and device design rather than rely on nominal ampere-hours alone.

Stored spares need a policy too. Track storage age, conditions, lot information, and rotation.

How to Plan Solar-Powered RTLS Deployments

Solar power sounds like the end of battery maintenance. It is not.

A solar device combines generation, storage, consumption, seasonal variation, shading, dirt, mounting angle, and weather. The European Commission’s Joint Research Center provides PVGIS tools for solar resource and photovoltaic performance planning. Its off-grid model uses time-varying consumption and solar data to simulate energy flow into and out of battery storage, including how often the battery reaches an empty state. (4)

Die Lansitec Solar-Bluetooth-Gateway combines a 3 W solar panel with a 5,300 mAh rechargeable battery: one month of continuous operation in rainy conditions under a defined profile: continuous Bluetooth reception and a 60-second LoRaWAN reporting interval. That is useful resilience data, but not a universal promise for every latitude, winter, mounting position, or reporting setting.

Check the worst month, not the annual average. Inspect for new shading and dirt too. Both can quietly change the energy balance.

How Many Spare RTLS Tags and Gateways Do You Need?

RTLS buyers often calculate quantity from the map: 800 badges, 1,500 asset tags, 60 Gateways. Operations should calculate a second number: how many units must be in stock to keep those quantities available?

Cause	Beispiel	Response
Energy	Badge awaiting charge	Turnaround pool
Failure	Broken enclosure or battery fault	Ready spare
Logistik	Replacement in transit	Buffer stock
Operations	Lost, quarantined, reassigned	Contingency

Stock levels depend on failure history, procurement lead time, access difficulty, and business criticality. A two-day event may need a larger ready pool; a stable factory may need less local stock when lead times are short.

A useful rule is to size spares from the recovery time you promise. If a failed worker badge must be replaced before the next shift, stock and charging capacity must make that possible.

Why RTLS Battery Planning Should Be Part of Your SLA

RTLS service-level agreements usually focus on accuracy, latency, update rate, and uptime. Add energy availability.

Track:

• percentage of assigned tags reporting as expected;
• devices below the defined battery threshold;
• maximum time to replace or recharge a device;
• spare coverage in days at the observed consumption rate.

This turns dead-tag surprises into a maintenance queue. It also improves architecture comparisons. A cheap tag that needs frequent handling may cost more over five years than a more expensive long-life device. Conversely, installing a 38,000 mAh gateway where mains power already exists may add unnecessary battery inventory.

The best choice depends on access, labor, reporting needs, and failure consequences.

Choosing the Right RTLS Power Architecture

Our device range illustrates a broader RTLS principle: do not force one power model across every layer.

For outdoor collection points, the Solar Bluetooth-Gateway uses a 3 W panel and 5,300 mAh rechargeable battery. For locations without power where very long autonomy matters, the Macro Bluetooth-Gateway uses a 38,000 mAh Li-SOCl2 configuration. Rechargeable badges support reuse and low-battery alerts. The Sendungsverfolgungsetikett uses a disposable battery and a defined low-frequency GNSS profile. Container and remote-asset Tracker use larger primary batteries to reduce the frequency of interventions.

We’ve seen buyers focus heavily on radio coverage and positioning accuracy. Fair enough. Once the system scales, though, power architecture becomes operational architecture too.

The goal is not maximum battery life everywhere. It is predictable availability at the lowest realistic maintenance cost.

RTLS Battery Planning Checklist

Before purchase, ask for a battery estimate for your actual configuration. Document who owns every maintenance action. Validate worst-case temperature and radio conditions. Size charging and spares from turnaround requirements, not guesswork. Finally, monitor low-battery and missing-device trends as operating KPIs.

Do that, and battery life stops being a marketing number. It becomes a managed part of RTLS availability.

Referenzen und weiterführende Literatur:

1. Bluetooth SIG: Bluetooth Core Specification, Generic Access Profile
2. National Laboratory of the Rockies: Battery Lifespan
3. Saft: The Seven Passivation Pitfalls and How to Avoid Them
4. European Commission Joint Research Center: PVGIS Off-Grid PV Systems