A customer books air freight for finished goods, and the forwarder comes back with one document request: the UN38.3 test summary for the battery inside the product. Not the CE declaration, not the radio test report - the battery document. For most exporters this is the first time they hear the term.
UN38.3 is not a market approval and it is not a certificate that gets attached to a product. It is a transport requirement, and it applies to the cells and batteries themselves - including the ones already fitted inside your finished product. Here is how to work out whether your product is affected, what the carrier actually wants to see, and why a battery report that exists is not always the battery report that works.
What UN38.3 actually is
UN38.3 is Section 38.3 of the United Nations Manual of Tests and Criteria, Part III, under the heading Lithium metal and lithium ion batteries. It defines eight test procedures that a lithium cell or battery must pass before it can be offered for transport.
Those tests are not written into a market access law. They are adopted by the transport regulations instead: the ICAO Technical Instructions and IATA Dangerous Goods Regulations for air, the IMDG Code for sea, ADR in Europe and 49 CFR in the United States for road. That is why the request almost always arrives from a freight forwarder, an airline or a marketplace logistics requirement, rather than from a regulator's letter.
Two consequences follow, and they matter more than the test list itself:
- The deliverable is not a certificate. A laboratory issues a UN38.3 test report; the UN38.3 test summary is produced from that report. No authority issues a "UN38.3 certificate", so when a supplier forwards a document with that title, read what is actually inside it.
- It is separate from your product certification. Passing UN38.3 does not make a product compliant anywhere, and holding a CE or FCC report does not exempt a battery from UN38.3. They answer different questions, ask different things of you, and are usually handled by different people on the same project.
Who asks for it, and when
| Who asks | When it comes up | What they want |
|---|---|---|
| Freight forwarder or airline | Before booking air freight of cells, batteries, or products containing them | The UN38.3 test summary, plus the correct UN number and packing instruction |
| Shipping line | Before sea freight booked under the IMDG Code | The same test summary - the IMDG Code references UN38.3 |
| Marketplaces | During listing approval or a later battery compliance check | A test summary uploaded against the listing |
| Importer or end customer | During supplier qualification, or after a design change | Usually the report, sometimes the summary as well |
The trigger is shipment, not sale. A product can sell domestically for months without anyone mentioning UN38.3, and the question appears the moment the goods move internationally - or the moment a platform reviews the listing.
Does your product need it? Three questions
- Is there a lithium cell or battery anywhere in the shipment? A pouch cell, a cylindrical pack, a coin cell holding up the memory of a controller, a battery inside the remote control packed in the same carton. If it is lithium, it is in scope.
- Is the battery travelling with the product? Installed in the device, packed alongside it, or shipped loose - all three are covered. The transport rules treat "battery contained in equipment" as its own category with its own UN number, but the battery design itself still has to have been tested.
- Has that cell or battery ever been type-tested to UN38.3? The requirement applies to lithium cells and batteries manufactured after 30 June 2003, so for a current product the honest answer should be yes. If your supplier cannot produce the report, the more useful conclusion is that they do not know which cell they are building with - which is worth resolving before the shipment, not after.
One narrow exception is worth knowing because it gets repeated far too widely: button cells installed in equipment, including cells soldered directly onto circuit boards, are carved out of the UN38.3 test summary requirement. It is a narrow carve-out. The rechargeable pouch and cylindrical cells used in power banks, speakers, wearables, tools and most IoT devices are not inside it.
The eight tests, briefly
All eight have to pass on a design before the report supports shipment. T.1 to T.5 run in sequence on the same samples; T.6 and T.8 use fresh samples.
| Test | What it simulates |
|---|---|
| T.1 Altitude simulation | Low pressure in an aircraft cargo hold - 11.6 kPa, held for at least 6 hours |
| T.2 Thermal test | Repeated cycling between hot and cold extremes |
| T.3 Vibration | Sustained transport vibration, swept across three axes |
| T.4 Shock | A sharp mechanical impact during handling |
| T.5 External short circuit | Terminals shorted at an elevated ambient temperature |
| T.6 Impact / crush | Mechanical damage to the cell |
| T.7 Overcharge | Charging a rechargeable battery well beyond its limits |
| T.8 Forced discharge | A cell drained in reverse by the other cells in the pack |
The pass criteria are physical: no leakage, venting, disassembly, rupture or fire, and for the environmental tests a defined proportion of the pre-test open-circuit voltage has to survive. There is no partial credit. One item failing means the design does not ship as tested.
Cell, battery, and battery inside a product
This is where most of the delay in battery projects comes from, so it is worth being blunt about the levels:
- Cell - the individual electrochemical unit. Cell-level testing is what most cell makers and trading suppliers can produce, because it is the document their own customers ask them for.
- Battery or pack - the assembled article: cells plus protection circuit, wiring, connectors and housing. Tested separately, with its own report.
- Battery installed in equipment - the battery is still the tested article. Fitting it inside a product changes the UN number and the packing instruction; it does not remove the testing obligation.
A cell report does not cover a pack. If you buy cells and have them built into a pack, the cell report you received at the start of the project does not answer the question your forwarder will ask about the finished unit.
The test summary is the document that actually gets checked
Since 1 January 2020 a passed test is not enough on its own: the manufacturer, and every subsequent distributor, is required to make a UN38.3 test summary available. Carriers work from that summary at booking and at inspection, and it is a far shorter document than the report.
A usable test summary carries, at minimum:
- Name and contact details of the cell, battery or product manufacturer
- Name and contact details of the testing laboratory
- A unique test report identification number, and the date of the report
- A description of the cell or battery: chemistry - lithium ion or lithium metal - mass, watt-hour rating or lithium content, physical description, and model number
- The list of tests performed, with pass or fail results
- A reference to assembled battery testing where applicable, and to the edition of the Manual of Tests and Criteria used
- A signature, with the name and title of the person signing it
When a summary arrives with no laboratory name, no report number, or a checklist that is not tied to any report, it is not a test summary. It is a supplier datasheet with the words UN38.3 printed on it, and both airlines and marketplace reviewers are becoming better at spotting the difference.
When an existing battery report stops applying
A UN38.3 test is a type test. It describes one configuration, and the report has no fixed expiry date in the sense people usually assume - what changes is whether the article you are shipping still matches the article that was tested. A retest or a documented engineering assessment is needed when the design moves, for example:
- A different cell model, chemistry or supplier, even at the same rated capacity
- A different pack construction: cell count, series or parallel arrangement, housing, potting, wire gauge
- Changes to the protection circuit or BMS that alter overcharge behaviour
- An increased capacity or a change to the rated voltage of the pack
Cosmetic changes - a label, a colour, a laser marking - do not. The test is whether the article that has to survive the eight tests is still the same article.
Situations that come up in real projects
The report describes the cell, but the shipment contains a pack. A supplier forwards a UN38.3 report covering a 3.7 V lithium-ion cell, while the products being shipped contain a four-cell pack with a protection board. The report is genuine, and it is not the document the forwarder needs. Before the pack is built, it is worth settling who will test the assembled article - it is a much cheaper conversation than the one held the week the goods are due to fly.
The battery was changed after the report was issued. Batteries get swapped for a cheaper equivalent during cost-down, on the reasonable-looking basis that the dimensions, voltage and capacity match. Capacity is not the only variable: cell construction and protection behaviour decide how the design fares in vibration, impact and overcharge. A cheaper cell with the same rating is a different article, and the existing report stops describing the product that is being shipped.
The forwarder asked for a summary and was sent the full technical report. Carriers use the summary because it is structured for their check. Sending a sixty-page report instead usually means the shipment sits while somebody extracts the fields they need. Ask the laboratory for the test summary at the time of testing, and keep it somewhere you can email in a minute.
A listing was blocked over battery paperwork. This is increasingly common on battery products, and it is a document problem rather than a design problem: either the summary existed but had never been uploaded against the listing, or it named a model that did not match the listing title. Which of the two it is decides how long the fix takes.
UN38.3 is not the only battery question
| The question | Standard or framework | Who it answers to |
|---|---|---|
| Can this battery be transported? | UN38.3 | Air, sea and road transport regulations |
| Is this battery safe as a product? | IEC 62133-2 and its national adoptions | Buyers, CB scheme work, some market registrations |
| Can this product be sold in this market? | CE, FCC, RCM, KC and the rest | Market regulators |
Clients regularly arrive holding one of these and assume it covers the other two. When a product contains a lithium battery, the usual answer is that the shipment needs UN38.3 and the product needs its market documentation - two documents, two scopes, often two suppliers. If the destination is Europe, the product side of that list is set out in what electronics need to sell in Europe.
How we handle battery projects
Battery work is normally a two-track job, so we scope it that way: the transport test for the cell or the pack, and the market documentation for the product around it. We start from what you actually ship - cell model, whether the battery travels installed or separately, watt-hour rating or lithium content, destination and mode of transport - because that decides whether you need cell testing, pack testing or both, and it decides which UN number and packing instruction apply.
Reports are delivered with the test summary prepared at the same time, since that is the document you will be asked for first. Where a design change has already happened, we say plainly whether the change needs a retest or whether an engineering assessment can cover it. Battery transport testing sits alongside the EMC, radio and safety testing we run for the same products, so the two scopes are planned together rather than discovered in sequence. Where a shipment is already booked and the paperwork is the only gap, we work backwards from the carrier's checklist to establish which document is actually missing, rather than starting a new test programme by default. The battery-specific scope is described on the lithium battery and cell certification page.
If you are not sure whether the battery in your product has ever been tested, or which of the two documents your forwarder is asking for, send the cell or pack model, the watt-hour rating or lithium content, whether the battery ships installed or separately, and the destination and mode of transport. We will tell you what the shipment needs - and if an existing report already covers it, we will say so rather than quote you a test you do not need.