The honest answer is that runtime depends on the power bank and the heat setting. We don't publish a fixed number of hours, because results vary. Here is how to think about it and how to pick a power bank for the Wearable USB Heated Shawl.
How long does a heated shawl run on a power bank?
It depends on your power bank's capacity and the heat level you choose; a larger power bank on a lower setting runs longer.
We don't promise a set number of hours. Battery age, temperature, the power bank's efficiency and your heat setting all change the result.
What power bank does the heated shawl need?
Use a USB power bank with a 5V 2A output.
The shawl connects with a standard USB cable and is rated for a 5V 2A supply. A 5V 2A USB wall adapter also works at home. Many laptop and car USB ports supply less than 2A, so the shawl may not warm as well from them.
How can I estimate runtime myself?
Divide the power bank's usable energy in watt-hours by the shawl's power draw in watts; the result is a rough estimate, not a guarantee.
A power bank's capacity is usually listed in mAh at its internal battery voltage of about 3.7V. To convert, multiply mAh by 3.7 and divide by 1,000 to get watt-hours (Wh). Some energy is always lost converting to 5V USB output, so the usable amount is lower than the rated figure.
What does that look like for the 12,000 mAh power bank in the kit?
As an illustration only: 12,000 mAh at about 3.7V is roughly 44 Wh of rated energy, and a 5V 2A supply delivers at most about 10W.
Those two numbers are an upper-bound illustration at maximum draw, before conversion losses, not a promise of runtime. Real results vary, and lower heat settings draw less power and last longer.
Do lower heat settings last longer?
Yes. Lower heat levels draw less power, so the same power bank lasts longer than on the highest setting.
The shawl has 3 heat levels from about 104°F to 140°F. Many people warm up on high, then switch to a lower level to stretch the charge.
Does a bigger power bank last longer?
Generally, yes. A higher-capacity 5V 2A power bank stores more energy, so it can run the shawl longer than a smaller one.
Larger power banks are also heavier, so balance capacity against how comfortable it feels in the shawl's inner pocket.
How can I make a charge last longer?
Use a lower heat setting once you're warm, start with a fully charged power bank, and keep the power bank in the shawl's inner pocket rather than out in the cold.
Power banks tend to deliver less energy when they're very cold, so keeping it close to you helps. Turning the shawl off when you step away also saves charge. An older power bank may hold less than when it was new.
Is a power bank included with the shawl?
Not with the shawl alone ($79.99), but the Heated Shawl + Power Bank Kit ($94.99) includes a 12,000 mAh power bank.
See the Heated Shawl + Power Bank Kit or browse the Heated Shawls & Wraps collection. Shipping is free on every US order, and most orders arrive in about 4–10 business days.