Loadshedding has made reliable internet almost essential in South Africa. Many households have fiber installed, but during power cuts the WiFi immediately switches off—even though laptops and phones still have battery.
That is why mini UPS devices have become extremely popular. They are small battery backup units designed specifically to keep your router and fiber ONT powered when Eskom electricity goes off.
However, the biggest question people ask before buying one is simple:
How long will a mini UPS actually keep my WiFi running?
The answer is not the same for everyone. Runtime depends on your router’s power usage, the fiber ONT, and the battery size of the UPS itself. In this guide, we explain the real runtime you can expect in South African loadshedding conditions.
What a Mini UPS Actually Powers
A mini UPS does not power your whole house.
It is designed only for low-power network devices.
Normally it powers:
• WiFi Router
• Fibre ONT (the small fibre box on the wall)
• Sometimes a mesh WiFi node
It does NOT power:
• TVs
• PCs
• Gaming consoles
• Microwaves
This is important because runtime depends on how many devices you connect.
Typical Power Usage of Fibre Internet Equipment
Most people don’t realize how little electricity their internet equipment uses.
Typical South African fiber setup:
| Device | Average Power Use |
|---|---|
| Fibre ONT | 6W – 12W |
| WiFi Router | 8W–18W |
| Total | 14W – 30W |
This low usage is exactly why a mini UPS works so well during loadshedding.
How Mini UPS Battery Size Affects Runtime
The most important number on a UPS is mAh (milliamp-hours).
This is the battery capacity.
General guideline:
| UPS Size | Expected Runtime |
|---|---|
| 8 800 mAh | 2–3 hours |
| 10 400 mAh | 3–4 hours |
| 15 600 mAh | 4–6 hours |
| 20 000 mAh+ | 6–10 hours |
In Stage 4 loadshedding (2-hour outage), almost any decent mini UPS will keep your WiFi on the entire time.
Stage 6 (4-hour outage) requires a higher capacity model.
Real South African Runtime Example
Let’s use a normal home fiber setup:
• 12W router
• 8W fibre ONT
Total usage = 20W
A 15 600 mAh mini UPS typically runs this setup for about 5 hours.
That means:
Stage 2 ✔
Stage 4 ✔
Stage 6 ✔ (most of the time)
This is why mini UPS units are one of the most cost-effective loadshedding solutions in South Africa.
Why Some People Get Only 1 Hour
If your UPS only lasts 1 hour, it is almost always one of these:
- You did not connect the fibre ONT (internet still dies)
- Wrong voltage cable used
- Cheap UPS with fake battery capacity
- Too many devices connected (like a TV box)
Mini UPS devices are built specifically for networking equipment—not entertainment systems.
How to Extend Mini UPS Runtime
You can significantly increase runtime by:
• Turning off unused mesh nodes
• Disconnecting USB charging ports
• Using a low-power router
• Charging the UPS fully between outages
Also remember: after multiple loadshedding cycles in one day, runtime becomes shorter because the battery cannot fully recharge.
Best Mini UPS Options for South Africa
If you want to see recommended models that can handle Stage 4 and Stage 6 outages, read our full guide:
👉 Best Mini UPS for WiFi Routers South Africa (2026)
FAQ Section
Can a mini UPS last 4 hours?
Yes, but only higher capacity models (around 15 600 mAh or larger). Smaller units may only last 2–3 hours.
Does a mini UPS use a lot of electricity?
No. They charge slowly and use less power than most household appliances.
Will a mini UPS damage my router?
No. They are specifically designed for routers and provide stable voltage.
Do I need to power the fiber ONT too?
Yes. If the ONT is off, your internet will not work even if the router stays on.
Final thought
For most South African households, a mini UPS is the simplest and cheapest way to keep internet working during loadshedding. The actual runtime depends mainly on battery capacity and how many devices you connect, but a good quality unit can easily cover typical Stage 4 outages and often most Stage 6 schedules as well.
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