How to ship lithium batteries from China
UN38.3, MSDS, watt-hour limits, air and sea restrictions, and why the power bank you want to import may not be allowed to fly.
Lithium batteries leave China if the UN38.3 report covers the exact cell and pack model you are buying and if the watt-hour rating fits the band your carrier accepts: below 100 Wh most products can fly as cargo, between 100 Wh and 160 Wh the airline’s express approval is required, and above 160 Wh air transport is out. The conversion is arithmetic: watt-hours = milliamp-hours × 3.7 ÷ 1,000; a 20,000 mAh power bank is 74 Wh and a 30,000 mAh one is 111 Wh.
Almost every lithium hold-up happens before the problem becomes logistical: the importer received a PDF with a logo on it and did not check which model it covered.
UN38.3, MSDS and product certificate: three documents that are not the same
- UN38.3. The transport test: eight tests — altitude simulation, thermal, vibration, impact, external short circuit, crushing, overcharge and forced discharge — on a specific cell and pack model. It is what certifies that the battery can travel; without it, no airline and no shipping line accepts the cargo.
- MSDS / SDS. The material safety data sheet: composition, hazards, response to a spill or a fire. It does not say whether the product works. It accompanies the UN38.3 on every shipment.
- Product certificate. What allows the product to be sold at destination: electrical safety, electromagnetic compatibility, wireless homologation or health regulation. It is a market requirement, not a transport one.
You can receive all three, two, or none. And you can receive the correct MSDS alongside a UN38.3 for a different cell, which is worse than having nothing because it looks resolved.
The UN38.3 report is tied to a model, not a brand
The UN38.3 report covers one specific cell and pack reference with its model number, not the manufacturer’s entire catalogue. This is the part almost nobody checks, and it is where shipments are lost.
When the factory switches cell supplier to save cost, the old report stops being valid even though the product looks unchanged. This is cell substitution, and it is the most frequent reason a shipment falls over at the airline’s review.
There are three things to verify: that the report’s cell model matches the datasheet; that the pack model corresponds to the product you are going to receive; and that the laboratory signing it is identifiable. If the report is for a cell and your product is a pack assembled by another factory, the pack test is missing: this is common, because the assembler buys cells that already have UN38.3 and has not tested the assembly.
Since 1 January 2020 what circulates is the UN38.3 test summary, not the full report. It is enough to ship; a letter of conformity with no laboratory behind it is not.
The watt-hour thresholds and what they change
Two thresholds structure lithium transport, and they are expressed in energy: 20 Wh for a standalone cell and 100 Wh for an assembled battery define what the regulation considers “small” batteries. Above that, the shipment moves into the fully regulated category, with approved packaging and a dangerous goods declaration. Because the label is almost always in mAh, the conversion matters:
| Nominal capacity (mAh at 3.7 V) | Energy | Practical situation |
|---|---|---|
| 10,000 | 37 Wh | Flies as cargo with UN38.3 |
| 20,000 | 74 Wh | Flies as cargo with UN38.3 |
| 26,800 | 99.2 Wh | Just below 100 Wh |
| 30,000 | 111 Wh | Outside the 100 Wh band: cargo aircraft only |
| 43,200 | 159.8 Wh | Just below 160 Wh |
| 50,000 | 185 Wh | Above 160 Wh: air is ruled out |
What can fly as cargo and what has to go by sea
Lithium batteries travelling on their own, without equipment, are prohibited as cargo on passenger aircraft. Section II of packing instructions 965 and 968, which allowed small standalone batteries to be shipped with reduced formalities, was removed with a transitional period that ended on 31 March 2022. Since then every shipment of standalone batteries — including a power bank — goes by cargo aircraft, with a class 9 label and a dangerous goods declaration.
The distinction that opens doors is the finished-product one:
| Configuration | Example | Air route |
|---|---|---|
| Standalone battery (UN3480, PI 965) | Power bank, spare cell | Cargo aircraft only; prohibited on passenger aircraft |
| Packed with equipment (UN3481, PI 966) | Product and battery in the same box, not installed | Passenger hold permitted with limits |
| Contained in equipment (UN3481, PI 967) | TWS, watch, speaker with the cell inside | The most permissive configuration |
Since 2016, batteries travelling on their own are offered for transport at a maximum of 30% of their nominal capacity, and since 1 January 2026 that limit was extended to batteries packed with equipment when the cell exceeds 2.7 Wh. A TWS set, with cells below that threshold, falls outside; a 20 Wh speaker packed next to the cable meets it.
Sea freight is a different regime: under the IMDG code the cargo is still class 9 and still requires the UN38.3 and the safety data sheet, but there is no state-of-charge limit and no passenger-aircraft prohibition. Once the product goes past the comfortable air band, consolidated sea freight becomes the only route.
Capacity is a logistics decision, not a marketing figure
Choosing 30,000 mAh instead of 26,000 mAh can add a month to every replenishment. It is the difference between a product that travels in the hold in twenty-odd days and one that only ships by cargo aircraft or by sea.
If your model depends on fast replenishment — high marketplace turnover or a marked season — then battery capacity is a product decision just like price: a product crosses the threshold and it does not go up a percentage, it changes the entire mode of transport, and with it the capital tied up in transit.
Which products in the electronics catalogue are affected
| Product | Typical cell capacity | Effect |
|---|---|---|
| TWS earbuds | On the order of 1 to 3 Wh per unit with the case | Frictionless air; what gets checked is the pack’s UN38.3 |
| Watch or band | 1 to 2 Wh | Frictionless air |
| Portable Bluetooth speaker | 7 to 37 Wh | Normally air; the large models approach the threshold |
| Power bank 10,000–20,000 mAh | 37 to 74 Wh | Air as cargo, with UN38.3 and state-of-charge control |
| Power bank 30,000 mAh or more | 111 Wh and above | Cargo aircraft or sea only |
The power bank, the best-selling unit in the consumer electronics catalogue, decides the route for the whole operation.
Mexico and Brazil: the same in the air, different at destination
Lithium transport rules are the same for Mexico and for Brazil, because they are set by international regulation and adopted by airlines and shipping lines. What changes is what has to be done before and after the shipment.
In Mexico, a product with a battery may require a NOM certificate, whose applicability depends on the tariff fraction and the specific category. The certificate is obtained on the finished product, after manufacturing and before shipment, and the classification of lithium batteries sits in chapter 85 of the TIGIE.
In Brazil the body that appears first is not Inmetro but ANATEL. ANATEL Act No. 5155 of 17 April 2024 set the safety requirements for mobile phone chargers and replaced the previous reference to IEC 60950-1 with IEC 62368-1. Power banks with a USB output are treated in practice as a product subject to ANATEL homologation for containing a lithium battery, and the certificate must be held by a Brazilian company.
Commercial sources in the sector do not agree on whether Inmetro certification is also required. Confirm it with the designated certification body before producing.
These limits change: confirm them shipment by shipment
The lithium thresholds are set by IATA in its dangerous goods regulations, which are revised every year, and each carrier adds its own restrictions on top of the minimum. A number read in an article — including this one — is not a shipping authorisation.
The regulations expand frequently: the 67th edition, in force since 1 January 2026, extended the 30% state-of-charge limit to new configurations, and in 2026 ICAO and IATA added by addendum restrictions on passengers carrying power banks, with unit caps and a ban on putting them in checked baggage. The exact dates vary between airlines.
The only figure that counts is the one your carrier confirms to you in writing for that specific shipment.
Cell grades: A, B and recovered
Three cell origins coexist in Shenzhen: grade A, grade B and cells recovered from dismantled packs.
- Grade A. Meets the manufacturer’s specification.
- Grade B. Cells that failed the manufacturer’s control but work: more variation between units and fewer cycles.
- Recovered. They come from dismantled packs; they have already used cycles and their remaining capacity is an unknown that nobody documents.
The problem is not that grade B cells exist: it is that they are sold as grade A. What separates them is traceability — brand, model and batch — and a real capacity test on a sample from the batch, which is what a pre-shipment inspection is for.
Why a 20,000 mAh power bank delivers 11,000
The capacity printed on the box is the cell’s, measured at its nominal voltage, 3.7 V. What comes out of the USB port is at 5 V, and the circuit has to step the voltage up, which consumes energy as heat. The arithmetic is 20,000 mAh × 3.7 V = 74 Wh. Those 74 Wh, delivered at 5 V with 85% efficiency, give 12,580 mAh; with a cheap circuit, around 75%, they fall to about 11,100 mAh.
The “20,000” and the “11,000” can describe the same product without either being a lie. What is a problem is not knowing it when you set your price and promise a number of charges to the end buyer. What is directly an infringement in Brazil is declaring inflated capacity: ANATEL rules prohibit capacity marking that does not correspond to the real figure.
What to ask the factory before paying the deposit
- The UN38.3 test summary with the cell and pack model number, checked against the datasheet.
- The safety data sheet (MSDS) for that specific cell.
- The brand, model and batch of the cell, in writing.
- The declared capacity in Wh, not only in mAh.
- The carrier’s confirmation that this capacity and this route can be shipped, with the date.
- The destination certification — NOM in Mexico, ANATEL in Brazil — before shipment.
MeliPrep publishes what the work behind this list costs: documentary supplier verification is USD 349 per supplier and pre-shipment AQL inspection USD 299 per inspector-day, both listed on the pricing page. Coordination of UN38.3, MSDS and destination certifications is quoted by standard and category, with laboratory fees billed at cost.
A supplier who delivers those six points without argument is ready to export. One who answers “the battery is good quality, don’t worry” is telling you the problem will show up at the port.