I opened a 9,000,000mAh power bank from eBay to learn the truth - here's what I saw

Source: ZDNet

Bold claims! – Adrian Kingsley‑Hughes/ZDNET

A power bank boasting a massive capacity of 9 million mAh that fits in the palm of your hand—for just a little over $10—sounds too good to be true, doesn’t it? A reader brought this eBay listing to my attention and asked whether the claims were legitimate. I was skeptical, but I decided to investigate—all in the name of science.

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Putting the 9 million mAh claim into perspective

The $150 Anker PowerCore 24K has a capacity of 24 000 mAh and weighs 1.3 lb. To reach 9 million mAh you’d need 375 of those units—over $35 000—and it certainly wouldn’t fit in the palm of your hand.

So I ordered one of the purported “9 million mAh” power banks and waited a few days for delivery.

What I received

Image: I don’t think this is a 9,000,000 mAh power bank! – Adrian Kingsley‑Hughes/ZDNET

The packaging made no bold claims about the promised (and unrealistic) capacity, and a plethora of typos did nothing to inspire confidence.

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The power bank arrived dead. Despite multiple attempts to charge it, nothing worked—it was completely unresponsive out of the box.

Image: The power bank was totally dead. – Adrian Kingsley‑Hughes/ZDNET

I considered invoking the “warranty,” but I doubted it would help.

Image: My “warranty certificate.” – Adrian Kingsley‑Hughes/ZDNET

Taking it apart

I opened the unit using a safer plastic prying tool instead of a metal spudger:

• Metal spudger: (not used)
• Plastic prying tool: (used)

While poking inside, the power bank blinked to life for a few seconds.

Image: Poking inside the power bank brought it to life, even if only for a few seconds. – Adrian Kingsley‑Hughes/ZDNET

After applying a bit of force, the case popped open and I discovered the problem: one of the battery wires was disconnected, a fault that not only prevented operation but also posed a risk of short‑circuiting or fire.

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Image: The red wire was just floating about! – Adrian Kingsley‑Hughes/ZDNET

Inside the pack

The cells were all no‑name 18650 lithium‑ion cells. I measured each at roughly 2 000 mAh—likely old “recycled” cells or seconds, since even a cheap 18650 typically offers about 2 300 mAh.

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Three cells at ~2 000 mAh each give a total pack capacity of ≈ 6 000 mAh, a far cry from the advertised 9 000 000 mAh.

Image: These 18650 cells are likely to be old “recycled” cells or seconds. – Adrian Kingsley‑Hughes/ZDNET

Bottom line

Exaggerated claims dupe buyers into purchasing poorly assembled, low‑quality power banks. If you need a cheap, reliable unit, it’s worth spending an extra ten dollars for something like the Baseus 10 000 mAh power bank for $20 rather than falling for impossible specs.

Baseus Portable Charger 10 000 mAh

That way, you get a good‑quality power bank that delivers what it promises, will give you several years of service, and won’t be a potential fire hazard.