Whsahans B21 20,000mAh 5V Heated Clothing Power Bank

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Product guide

Whsahans B21 20,000mAh 5V Heated Clothing Power Bank

Whsahans B21 is a rechargeable 5V battery pack for compatible heated clothing, with a listed 20,000mAh capacity and USB power-bank use. It has no DC output and is not suitable for 7.4V heated garments, so check your garment’s required voltage and connector before buying.

At a glance

Made for compatible 5V heated clothing, including heated jackets, vests and pants, according to the listing.
The listing also describes use as a power bank for smartphones and other electronics.
An automatic-start feature is claimed when the pack is connected to heated clothing.

Price

$26.33Save 15%

Reference price: ~~$30.98~~

Price checked: Nov 12, 2026

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Often bought together

KOVNLO Womens Heated Vest, 5 in 1 Smart Controller, Lights-out Design, Electric Heated Jackets (Battery Pack Not Included)

$59.99

Pros and cons

Pros

The stated 20,000mAh capacity is intended to support extended heated-clothing use, and it can also charge compatible electronics.
Automatic start may simplify battery changes when used with compatible heated garments.
Overvoltage and short-circuit protection are listed among its features.

Cons

At 370 g, the listed battery weight may be noticeable when carried in clothing.
It cannot power 7.4V heated clothing and has no DC output.

Technical specifications

11 specifications

Identity
Brand	Whsahans
Model	B21

Power and battery
Capacity	20000 milliamp_hours
Output voltage	5 volts
Output current	2 A
Battery cell type	Lithium Ion
Rechargeable	Rechargeable
Number of batteries	1 Lithium Ion batteries required. (included)

Physical details
Color	Black
Battery weight	370 g

Features
Special features	Over Voltage Protection, Portable, Short Circuit Protection

What to know before buying

Listing details to confirm

The claimed heating runtime is inconsistent across listing sections: 6–20 hours in one feature, 5–15 hours in another, and up to 15 hours in the detailed claims. Treat runtime as a mode-dependent estimate, not a settled figure. The listed weight also differs between 370 g in product details and 398g/14oz in the product parameters. Confirm your garment requires 5V USB power, since this pack has no DC output and is not for 7.4V clothing. The stated charge-count claims are manufacturer estimates.

Who is it for?

A good fit for

People with heated clothing that specifically accepts 5V USB power.
Buyers seeking a battery pack that can also charge phones or other compatible electronics.
Those wanting a spare power source for compatible heated garments.

Less suited to

People whose heated garments require 7.4V or a DC connector.
Buyers prioritizing a lightweight battery, given the listed 370 g weight and customer feedback describing it as heavy.

Whsahans B21 20,000mAh 5V Heated Clothing Power Bank · photo 2 — Additional product photo 2

Customer reviews on Amazon

4.4 / 5 · 714 ratings

5 stars74%74%
4 stars12%12%
3 stars7%7%
2 stars1%1%
1 star6%6%

Customer feedback describes the pack as a useful backup for heated gear, with some buyers reporting warmth through long shifts. Customers also report mixed charging speed and value, and concerns about weight and compatibility with some vests. These reports matter because the pack is listed at 370 g and is limited to compatible 5V garments. The stated runtime varies across the listing, so customer reports do not establish a guaranteed duration.

Positive themes

Customers report useful performance as a heated-gear battery backup and long-lasting warmth.

Negative themes

Some customers describe the pack as heavy and report that it does not work with every heated vest.

Mixed feedback

Charging speed and value for money receive mixed customer feedback.

Frequently asked questions

Will this power a 7.4V heated vest?

No. The listing specifies 5V output, says there is no DC output and states that it is not suitable for 7.4V heated clothing.

How long does it run heated clothing?

The listing gives inconsistent estimates, ranging from 5–15 hours to 6–20 hours. It also gives mode-specific claims of 5–7 hours on high, 9–12 hours on medium and 15–20 hours on low. Actual runtime is not established here.

Can it charge a phone?

The listing says it can charge smartphones and other electronics. Check that your device and cable are compatible with its stated output.

Does it start automatically with heated clothing?

The listing claims it powers on when connected to heated clothing and sleeps when not in use.