# Mini-UPS Dimensioning for Load Reduction: Keeping the ONT Alive Source: https://urbanx.co.za/knowledge-hub/competitive-security-edge-config-continuity/mini-ups-dimensioning **Answer:** Calculate Mini-UPS capacity as (ONT Watts + Router Watts) ÷ efficiency (0.85). A DC-to-DC Mini-UPS provides 0ms transfer time (no reboot), avoiding the post-loadshedding reconnect storm entirely. Match voltage exactly (12V/9V) and always over-specify amperage. Part of [Competitive Security, Edge Config & Continuity](https://urbanx.co.za/knowledge-hub/competitive-security-edge-config-continuity) · 11 min read · by UrbanX Edge Security & Resilience ### Mini-UPS Dimensioning for Load Reduction: Keeping the ONT Alive It is a common scenario in the 2026 South African gaming landscape: the lights go out, but you are in the middle of a high-stakes competitive match. Thanks to the evolution of our national grid, full-scale "loadshedding" has become a rarity, replaced by more surgical "load reduction" blocks aimed at high-demand areas. While the grid has stabilized, these localized interruptions still threaten to sever your connection at the most critical moments. In the framework of [Competitive Security, Edge Config & Continuity](/knowledge-hub/competitive-security-edge-config-continuity), maintaining uptime is not just about having a backup battery—it is about the precise technical dimensioning of your "Edge Layer" power supply. To keep your gaming session alive, you must keep two distinct devices powered: the Optical Network Terminal (ONT)—the white box where the fibre enters your home—and your WiFi router. If either drops power for even a millisecond, your session is terminated. Understanding the voltage and amperage requirements of these devices is the difference between a seamless transition and a frustrating disconnect. #### Load Reduction vs. Loadshedding: The 2026 Context In 2026, we have moved away from the blunt instrument of national stages. Instead, Eskom and local municipalities utilize "Load Reduction" to manage peak demand on specific feeders or to protect infrastructure in high-risk zones. These blocks are often shorter but can be more frequent in certain suburbs. Unlike the old days of four-hour outages, load reduction typically lasts two hours. This has shifted the market from massive, expensive inverters toward high-efficiency DC-to-DC Mini UPS units. These devices are purpose-built to power low-voltage networking gear without the massive energy loss associated with converting battery power back into 220V AC. #### Step 1: Identifying Your Power Profile (V and A) Before you buy a Mini-UPS, you must audit your hardware. Look at the stickers on the bottom or back of your ONT and your router. You are looking for two specific values: Voltage (V) and Amperage (A). #### The ONT (Optical Network Terminal) Most ONTs supplied by FNOs like Openserve, Vumatel, or MetroFibre operate on 12V DC. Their amperage draw is usually low, ranging from 0.5A to 1.5A. Typical Power Draw: 6W to 18W. #### The Router This is where things get tricky. While many modern routers use 12V, some older or specialized units (like certain TP-Link or Huawei models) use 9V or even 5V. High-performance gaming routers with multiple antennas often require higher amperage, typically 2.0A to 3.5A. Typical Power Draw: 12W to 42W. The Golden Rule of Voltage: You must match the voltage exactly. Plugging a 9V router into a 12V UPS port will likely fry the internal capacitors of your router. However, amperage is "pulled," not "pushed." It is perfectly safe to use a 3A UPS port for a device that only needs 1.5A, but you cannot do the reverse without overloading the UPS. #### Step 2: Calculating Total Wattage and Runtime Once you have your Amps and Volts, you can calculate your Total Wattage (W) using the formula: Volts x Amps = Watts. #### Example Calculation: #### ONT: 12V x 1.0A = 12W #### Router: 12V x 2.0A = 24W #### Total Load: 36W #### Dimensioning for Capacity (Watt-Hours) Mini-UPS capacity is usually measured in Watt-Hours (Wh) or Milliamp-Hours (mAh). For a reliable gaming setup, Wh is the more accurate metric. How do I calculate how long my Mini-UPS will last? To find your estimated runtime, divide the UPS capacity (Wh) by your total load (W), then multiply by 0.85 to account for efficiency loss. For a 36W load on a 65Wh UPS: (65 / 36) * 0.85 = ~1.5 hours. If you are facing a two-hour load reduction block, a 65Wh unit is likely the bare minimum for a high-performance gaming router. If you are using a standard ISP-supplied router, which usually draws less power, you could see upwards of 4 hours on the same unit. For users with particularly power-hungry setups, keeping an eye on [Clean Power vs. Modified Sine Wave](/knowledge-hub/competitive-security-edge-config-continuity/clean-power-router-lifespan) is vital, as the quality of the backup power directly impacts the longevity of your hardware’s sensitive power adapters. #### Step 3: Zero-Latency Switching (Bump-less Transfer) One of the most common complaints among South African gamers is: "I have a UPS, but my router still reboots when the power goes out." This happens because traditional AC-to-DC UPS units often have a "transfer time" of 10 to 20 milliseconds. While a PC might stay on thanks to its power supply capacitors, a sensitive router will detect this tiny gap and reboot. The Solution: DC-to-DC Mini UPS A DC-to-DC Mini UPS stays "in-line" between your wall socket and your device. Because it provides a constant DC stream, there is zero transfer time (0ms). The device never "knows" the power has failed, ensuring your session remains active. This is crucial for avoiding the dreaded "authentication loop" described in our guide to [Post-Loadshedding Reconnect Storms](/knowledge-hub/competitive-security-edge-config-continuity/reconnect-storm-delay). #### Advanced Tips for the Competitive Edge LiFePO4 vs. Li-ion: In 2026, Lithium Iron Phosphate (LiFePO4) has become the gold standard. These batteries can handle over 2,000 charge cycles compared to the ~500 cycles of standard Lithium-ion. If your area suffers from daily load reduction, Li-ion batteries will degrade and lose capacity within a year. Cable Quality: Many Mini-UPS units ship with thin DC "Y-splitters." For high-performance routers drawing more than 2A, these thin cables can cause a voltage drop, leading to instability or WiFi drops. Always use high-quality, thick DC bridge cables. Heat Management: Mini-UPS units generate heat while charging. Avoid stacking your router directly on top of the UPS, as the combined thermal load can lead to thermal throttling of the router’s processor, causing jitter. Auto-Reboot Prevention: Some ONTs are notoriously sensitive to voltage fluctuations when the grid returns. If you find your ONT acting up after power returns, it may be receiving "dirty" power through the UPS's bypass circuit. See [Clean Power vs. Modified Sine Wave](/knowledge-hub/competitive-security-edge-config-continuity/clean-power-router-lifespan) for stabilization tips. #### Summary: Securing Your Continuity Dimensioning your power backup is the final frontier of "Edge Layer" optimization. It ensures that your technical skill isn't undermined by infrastructure instability. By correctly matching your voltage, over-specifying your amperage, and calculating your runtime with a 15% efficiency buffer, you turn a potential disconnect into a minor blip that your opponent won't even notice. Take a moment today to look at the stickers on your gear. Do you have a 12V ONT and a 9V router? Does your current UPS provide enough Watt-hours for a full two-hour block? If your setup is failing you during transitions, our Support Robotics can help diagnose whether it's a power issue or a network authentication delay. Continuity is king in competitive gaming. Don't let a local power shift be the reason you lose your rank. ## Frequently Asked Questions **Can I use one Mini-UPS to power both my ONT and my Router?** Yes, provided the UPS has two output ports and the Total Wattage of both devices is less than the UPS's rated output (e.g., a 30W UPS cannot power a 36W combined load). Most high-end units in 2026 provide at least one 12V and one 9V/12V selectable port. **Why does my Mini-UPS beep when the power returns?** This is usually a notification that the unit has switched from battery mode back to mains power. However, if it beeps continuously, it may indicate an Overload—likely because your router is pulling more amperage than the port can provide. Double-check your amperage math using the formula in Step 2. **Will a Mini-UPS keep my internet working if the FNO's exchange goes down?** Usually, yes. FNOs (like Vumatel or Openserve) have large-scale battery backups at their local exchanges. However, during extended load reduction, these batteries can fail. Check the Network Status to see if a regional infrastructure failure is the cause of your disconnect rather than your local power. **My ONT is 12V but my router is 9V. Can I use the same UPS?** Only if the UPS has independent voltage ports. Many units offer a dedicated 12V port and a second port that can be toggled between 5V, 9V, and 12V. Never plug a 9V device into a 12V port. If you are unsure, use our Support Robotics for a hardware compatibility check. **Is it safe to leave the Mini-UPS plugged in 24/7?** Yes. These units are designed to act as a buffer. They manage the charging cycle of the internal battery and only use it when the mains voltage drops. This actually protects your gear from the "dirty power" surges common when the grid returns after load reduction. **How do I know when the battery in my UPS is dying?** If your 2-hour backup time has dropped to 30 minutes, the cells are reaching the end of their life. You can check the health of your connection under load via the Looking Glass; if you see high jitter only when on battery power, your UPS may be struggling to provide stable voltage.