How to Choose a Mini UPS for Your WiFi Router (Load-Shedding Guide)

When the power goes out, the WiFi goes with it, even though most internet lines in Bangladesh keep working during load shedding. A mini UPS is a small battery box that keeps your router (and often your ONU) powered, so video calls, online classes and work continue without a break.

1. Check what your devices need

Look at the small adapter that came with your router. It shows the output voltage (for example 12V or 9V) and current (for example 1A). Do the same for the ONU box from your internet provider. The mini UPS you choose must offer the same voltage on its output ports, and enough ports for every device you want to keep running.

• Router only: one matching DC output is enough.
• Router + ONU: choose a model with two DC outputs (often 12V + 9V, or 12V + 12V). Check that both voltages match your adapters.
• PoE devices (some routers, IP cameras): you need a mini UPS with a PoE port that matches the device.

2. Battery capacity and backup time

Capacity is written in mAh. More mAh means longer backup, but the real backup time depends on how much power your devices use. A quick estimate:

Backup (hours) ≈ mAh × 3.7 ÷ 1000 × 0.8 ÷ device watts

The 3.7 is the cell voltage, and 0.8 allows for conversion losses. A typical home router uses roughly 6–12 watts; an ONU adds a few more. You can find the watts on the adapter label (volts × amps). Our home page calculator does this maths for you.

3. Battery type and safety

• Lithium-ion (18650 cells): the most common, compact and light.
• LiFePO4: a safer, longer-lasting chemistry, usually a little bigger.
• Look for protection against overcharge, over-discharge and short circuit, and keep the UPS in a ventilated place, away from heat.

4. Practical tips

• Use the cables that come with the UPS, or DC cables with the correct plug size.
• Leave the UPS plugged in all the time; it switches over automatically when the power goes out.
• If your router has a USB-powered model, a power bank with pass-through charging may also work.

Browse our Mini UPS collection and compare the output ports and capacity on each product page. Not sure which one fits your router? Message us on WhatsApp with a photo of your router and ONU adapters and we will help you choose.