How long will a 20,000 mAh power bank run a Wi-Fi router?
About 5 h on a typical router setup (10 W), from 4 h 20 min to 5 h 40 min depending on how efficient the bank is.
The router carries the internet and, now that landlines are digital, often the home phone too. A 20,000 mAh bank holds about 74 Wh at its 3.7 V cells, of which about 75% typically reaches the USB port, less a little more for the 12 V cable.
The numbers
| Setting | Worst case | Typical | Best case |
|---|---|---|---|
| Small router (6 W) | 7 h 13 min | 8 h 20 min | 9 h 26 min |
| Typical router (10 W) | 4 h 20 min | 5 h | 5 h 40 min |
| Router and fibre box (16 W) | 2 h 42 min | 3 h 7 min | 3 h 32 min |
Most routers take 12 V from their own adapter, so a power bank needs a USB-to-12 V cable, which only works if the bank supports USB Power Delivery at 12 V or the cable boosts from 5 V. Check the voltage and plug size on your router's adapter first. With fibre, the separate box on the wall needs power too.
Other sizes
| Power bank | Energy | Typical |
|---|---|---|
| 10,000 mAh | 37 Wh | 2 h 30 min |
| 20,000 mAh | 74 Wh | 5 h |
| 26,800 mAh | 99 Wh | 6 h 42 min |
| 40,000 mAh | 148 Wh | 9 h 59 min |
Where to buy
Wi-Fi router
A 20,000 mAh power bank
Amazon links are affiliate searches for a type of product, not endorsements of a model; the site may earn a commission at no extra cost to you. Prices and stock change constantly.
When a power bank is not enough
A power station runs the same job from a mains socket, for far longer, and runs the things a power bank cannot: the fridge, the boiler's electrics, a mains electric blanket. For example, the Anker SOLIX C300 runs a Wi-Fi router for about 11 h 38 min.
If this is for a power cut
In a power cut the router often matters most: it carries the internet and, on a digital landline, the home phone.
Mini UPS for the router. Home phones now run through the broadband router, so when it goes off in a power cut the landline goes with it. A small battery box keeps the router, and the phone plugged into it, working.
Look for: DC outputs that match the voltage printed on your router's power adapter (usually 12 V), enough of them for the fibre box too if you have one, and a capacity in watt-hours.
Power bank, 20,000 mAh. Keeps a phone going for days if you use it sparingly.
Look for: Capacity in watt-hours as well as mAh (about 74 Wh for 20,000 mAh), USB-C in and out, and keep it charged.
Simple mobile phone. A basic mobile with a week of standby is the backup when the home phone dies with the router. Easy to use, and it stays charged far longer than a smartphone.
Look for: Large buttons, a loud ringer, a long stated standby time, and an emergency button if it will be used by someone who lives alone.
Amazon links are affiliate searches for a type of product, not endorsements of a model; the site may earn a commission at no extra cost to you.
More: Will your phone and internet work in a power cut?, and the power cut essentials list (US edition).
Did this match what you measured?
Nothing is sent anywhere unless analytics is switched on, and no text is collected.