How long will a 10,000 mAh power bank run a USB heated throw?
About 3 h 42 min on a medium setting (7.5 W), from 3 h 12 min to 4 h 12 min depending on how efficient the bank is.
A USB throw over the knees or in a bed is the cheapest warmth you can run from a battery in a power cut. A 10,000 mAh bank holds about 37 Wh at its 3.7 V cells, of which about 75% typically reaches the USB port.
The numbers
| Setting | Worst case | Typical | Best case |
|---|---|---|---|
| Low (5 W) | 4 h 49 min | 5 h 33 min | 6 h 17 min |
| Medium (7.5 W) | 3 h 12 min | 3 h 42 min | 4 h 12 min |
| High (10 W) | 2 h 24 min | 2 h 46 min | 3 h 9 min |
USB-A throws are limited to about 10 W, so they are gentler than a mains electric blanket. USB-C throws that ask for 12 V or more draw two or three times as much and empty a bank proportionally faster.
Other sizes
| Power bank | Energy | Typical |
|---|---|---|
| 10,000 mAh | 37 Wh | 3 h 42 min |
| 20,000 mAh | 74 Wh | 7 h 24 min |
| 26,800 mAh | 99 Wh | 9 h 55 min |
| 40,000 mAh | 148 Wh | 14 h 48 min |
Where to buy
USB heated throw
A 10,000 mAh power bank
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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 an electric blanket for about 7 h 13 min.
If this is for a power cut
Heating is what a battery does worst. In a power cut, warming people rather than rooms goes much further, and none of this needs a socket.
Hot water bottle and a vacuum flask. Boil water while you still can, keep it hot in a flask, and refill the bottle through the night.
Look for: A bottle made to BS 1970 in the UK, and a flask of a litre or more.
Hand warmers. Air-activated packs give hours of heat with no power at all, and a pocketful helps children and older relatives.
Look for: Long-duration packs, and the expiry date on bulk boxes.
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: How to keep warm in a power cut, and the power cut essentials list (US edition).
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