Power Banks

Power Bank Safety, Cell Selection and Shipping Rules

Why the cell decides whether a power bank passes UN38.3, what a 20,000 mAh rating really means, and how lithium shipping rules affect freight.

A power bank is the most regulated item in a typical accessories range, because it combines a lithium cell, a charging circuit and a radio or fast-charging protocol in a product people carry in a bag. Almost every serious problem in this category traces back to one component: the cell.

The cell is the product

	Grade-A, traceable	Unbranded / recycled
UN38.3	Passes with documentation	Usually fails or is undocumented
Capacity honesty	Matches the label	Often overstated
Cycle life	Predictable	Degrades early
Freight	Accepted by carriers	Refused, or seized

The price difference is real and it is the wrong place to save. A product that cannot be shipped is worth nothing, and a product that overstates capacity generates returns and reviews you cannot recover from.

Reading the mAh rating honestly

A 10,000 mAh power bank does not deliver 10,000 mAh to a phone. The cell capacity is measured at 3.7 V; the output is at 5 V or higher, and conversion losses apply. Expect roughly 60–70% of the labelled figure at the phone end. Two things follow: quote the cell capacity and the usable output separately in your marketing, and treat any supplier claiming 100% transfer with suspicion.

Protection and fast charging

Over-charge, over-discharge, over-current and short-circuit protection are non-negotiable, plus thermal protection on higher-power models. On the fast-charging side, confirm which protocols the product actually supports — PD, QC, PPS and the proprietary standards — because a mismatch between the label and the handshake is a common source of "it does not fast charge my phone" reviews. Our USB-C fast charging guide covers the protocol question in detail.

Shipping: the rules that decide your freight

• UN38.3 test summary — required for air and increasingly for sea; carriers ask for it by name.
• Watt-hour rating — determines whether the product can fly at all, and in what quantity per package.
• State of charge — air shipments generally require a partial charge.
• Lithium battery mark and labelling — on the carton, not just the unit.
• MSDS — provided with the shipment.

Practically: budget more time for a first battery shipment than for a cable order, and confirm the freight class before you promise a delivery date.

Frequently asked

Can you ship power banks by air?

Yes, with a current UN38.3 summary, correct declaration, packaging and state of charge. Sea is often the calmer option for volume.

Do you use branded cells?

Yes, with traceability. We will say which cell is in the sample and it will be the same cell in production.

What capacity should we launch with?

10,000 mAh is the volume sweet spot; 20,000 mAh sells to travellers and laptop users. See the power bank range.

Discuss a power bank programme