Do You Need a Power Bank for a Heated Jacket? What to Buy and How Long It Lasts

Thermza jackets don't come with a power bank — on purpose. Building one in adds cost, weight, and a battery you can't replace when it wears out. Instead, the jacket runs off any USB power bank you already own or can buy separately, which means you're not stuck buying a proprietary battery later. Here's what actually matters when you're picking one.

What the jacket needs

The jacket runs off a standard USB power bank — the same kind you'd use to charge a phone. There's no special charger to buy. If you already carry one for travel or work, there's a decent chance it'll work.

Capacity decides your runtime, not the jacket

How long the heat lasts comes down to the power bank's capacity (measured in mAh) and which of the 3 settings you run:

• Red — 113°F, the highest setting, draws the most power
• White — 95°F, medium, a good default for most cold-weather days
• Blue — 77°F, the lowest setting, stretches your runtime the furthest

A small power bank on the red setting might give you an hour or two. A larger one on white or blue can realistically get you through most of a day outside. If you know you'll want all-day heat, size up.

A rough way to think about it

You don't need to do the math yourself, but the pattern holds across USB-heated gear in general: doubling the power bank's capacity roughly doubles your runtime at the same setting. If a smaller bank gets you 90 minutes on white, a bank with twice the capacity gets you close to 3 hours.

What to look for when you buy one

• Capacity: bigger for all-day use, smaller is fine for a few hours at a game or a walk
• Size and weight: it rides in an inside pocket — a brick-sized bank gets old fast
• A sealed, name-brand cell with built-in safety protection: it sits against your body for hours, so skip unbranded ones from a random marketplace listing, and stop using any power bank that's swollen, damaged, or overheating

Already have one?

If you've got a phone power bank sitting in a drawer, try it before buying anything new. Most work fine. You'll only need a bigger one if you're planning to wear the jacket for a full day on the highest setting.

Check out the Thermza Heated Jacket — 8 heating zones, 3 settings, runs on a power bank you control.