Why Are an Increasing Number of Smart Streetlight Projects in South America Ultimately Choosing a "48V DC + PoE" Architecture?

Frankly speaking, three years ago, almost no one would have asked this question.
Back then, most projects followed a default logic: solar power is generated, converted into 220V AC via an inverter, and then used to power various devices. This approach had operated for decades during the era of pure street lighting without encountering any major issues.
However, today, smart streetlights are no longer merely streetlights. A single light pole often integrates a host of components: HD cameras (CCTV), 5G small cells, LED information displays, environmental sensors (measuring temperature, PM2.5, and noise), emergency call terminals, and wireless access points (APs).
In other words, the pole has evolved into an outdoor edge computing node.
This brings a problem to the fore: almost all of the aforementioned devices are DC-powered.
Converting DC power into AC power first, only to have each individual device convert it back to DC—this process in itself constitutes a wasteful expenditure of energy.
This is the fundamental reason why an increasing number of projects in Latin America have begun to re-evaluate their power supply architectures.

I. The Efficiency Issue: Every Conversion Consumes Energy
The complete power chain in a traditional AC architecture looks like this: Solar (DC) → Inverter → 220V AC → Device-internal Adapters → DC.
Each stage in this chain incurs conversion losses. The inverter itself typically operates at an efficiency of 92% to 96%, while the adapters within the devices account for an additional loss of 5% to 15%; when compounded, the overall efficiency loss can exceed 20%.
For projects connected to the utility grid, this level of loss remains within an acceptable range—the grid can readily compensate for it.
However, for off-grid solar systems, that 20% loss carries significant implications: it means you require a larger battery bank—or a greater number of photovoltaic panels—to ensure reliable operation throughout the night.
In contrast, the DC architecture features a much shorter power chain: Solar → MPPT Controller → Battery → 48V DC Bus → Individual Devices.
By eliminating the inverter stage, the system's overall efficiency is enhanced, battery runtime is extended, and operational stability during nighttime hours is significantly improved.

II. PoE: A Single Network Cable Solves Both Power Supply and Communication Challenges
PoE (Power over Ethernet) is by no means a new technology. The IEEE 802.3af standard was published in 2003, while IEEE 802.3bt (PoE++, supporting up to 90W) was standardized in 2018.
Its core logic is remarkably simple: use a single Ethernet twisted-pair cable to transmit both data and DC power simultaneously.
For smart streetlights, this translates to the following benefits: cameras do not require separate power cables; wireless access points (APs) do not require separate power cables; and certain communication devices can be powered and centrally managed directly by a PoE switch.
The impact at the construction level is substantial. In urban projects across Latin America, underground conduit routing is often complex, and labor costs are constantly rising. Eliminating one type of cable effectively eliminates one construction process and narrows the scope of troubleshooting required during subsequent maintenance.
Simply put: the fewer cables there are, the fewer potential points of failure exist.

III. Why is 48V the More Suitable Voltage Level?
The telecommunications industry has long adopted -48V DC (with negative grounding) as its standard power supply voltage. This standard applies to a wide range of equipment—including telecom base stations, industrial switches, and Small Cells—and has fostered a complete product ecosystem supported by established standards.
Compared to 12V or 24V systems, the advantage of 48V lies in the formula P = U × I (Power = Voltage × Current). Given a constant power output, a higher voltage results in lower current; this, in turn, reduces heat generation within the conductors, minimizes line loss, and lowers the requirements for the cable's cross-sectional area.
In other words: over the same transmission distance, a 48V system exhibits significantly lower line loss than 12V or 24V systems. This makes it better suited for long-distance power delivery and more compatible with high-power devices (such as 5G Small Cells).
For smart streetlight projects involving distributed deployments, this characteristic is of paramount importance.

IV. System Reliability: Complexity is the Arch-Nemesis of Outdoor Equipment
The most critical point—one that many people tend to overlook during the equipment selection phase—is this: the primary cause of project failure is rarely the quality of installation itself, but rather the inherent complexity of the system.
A traditional AC-based smart streetlight system typically comprises: an inverter (one unit), a charge/discharge controller (one unit), multiple device-specific power adapters (one for each connected device), an AC power distribution unit, and a vast network of AC cabling. Each and every one of these components represents a potential point of failure. The outdoor environment is inherently challenging—characterized by high temperatures, high humidity, salt spray, and frequent temperature fluctuations. Under such conditions, a single loose connector or a single aging adapter can bring an entire system to a standstill.
The centralized DC power supply architecture, however, is fundamentally an exercise in subtraction: it eliminates inverters and distributed adapters, utilizing PoE switches to centrally manage the power status of multiple devices. Fewer devices mean fewer points of failure.
For urban projects in Latin America—where maintenance resources are often limited—this inherent "structural simplicity" serves as a competitive advantage in its own right.

Conclusion
In my personal view, the future evolution of smart streetlights will not proceed solely along the path of "functional stacking." Projects that truly succeed in overseas markets must simultaneously satisfy three criteria: sufficiently high system efficiency, sufficiently low maintenance costs, and sufficiently stable long-term operation.
The "48V DC + PoE" architecture offers a relatively pragmatic solution in precisely this direction. While it may not represent the very latest technology, it currently stands as the most mature and proven approach for powering outdoor multi-functional poles.
What type of power supply architecture is currently being adopted by smart streetlight projects in your market? What challenges have you encountered during actual operations and maintenance? We invite you to share your thoughts in the comments section below.

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Post time:May - 26 - 2026