UN 38.3 testing explained

UN 38.3 is the test series a lithium cell or battery must pass before it ships by air, sea, road or rail. For air freight of lithium-ion, the state of charge must not exceed 30%. The test summary produced at the end is the document a freight forwarder asks to see, so in practice no summary means no shipment. It qualifies a design rather than a production batch. Change the cell, the enclosure or the wiring and the question of whether you are still covered comes straight back.

2026-08-05

## What is UN 38.3?

It is the transport test series for lithium cells and batteries. Passing it is required before shipment by air, sea, road or rail, which covers every route a European buyer is likely to use. The work is done on samples of a finished design at a laboratory. What you receive at the end is a test summary and that summary is the document that travels with the goods rather than the full report behind it.

## What do the tests do to a battery?

They put samples through the conditions transport can produce, in sequence, then ask whether the sample is still safe. Secondary summaries of the manual describe eight tests numbered T1 to T8: altitude simulation, thermal cycling, vibration, shock, external short circuit, impact or crush, overcharge and forced discharge. The parameters behind each of those, the number of samples and the cycling history a sample needs beforehand are set out in the manual itself. Read them there. This page names the tests so you can hold a sensible conversation with a laboratory. It does not give you pass criteria, because the manual was not opened while writing it.

## Why can you not ship without it?

Because the requirement sits before the shipment, not after it. The question a forwarder asks is whether the design has already passed, not whether you intend to test it next month. For lithium-ion moving by air there is a second and separate limit: state of charge must not exceed 30%. That one catches people who hold a valid summary and still watch the pallet get refused, since a fully charged pack is a different problem from an untested one.

## What does a test summary actually prove?

That samples of a design passed a defined sequence, on a date, at a named laboratory. It says nothing about the batch you are shipping this week. It does not replace your own incoming inspection either. Check that the summary describes your exact configuration: cell type, cell count, series and parallel arrangement, enclosure. If it describes a different variant, you are holding somebody else's document and that is a surprisingly common thing to find in a supplier email attachment.

## How does it relate to product standards?

UN 38.3 answers a transport question and nothing else. Whether your battery may be sold into a given European application is a separate matter with separate scopes: IEC 62133-2 for portable sealed lithium cells and batteries, IEC 62619 for industrial and energy storage cells and batteries. A cell can hold a clean transport summary and still be the wrong product for your market. The two get mixed up in supplier emails constantly, so ask which document you are being shown before you read it.

## How do you get tested?

Pick a laboratory that already runs the series for your battery format, then send the samples it asks for. Three things move the quote you get back: how many samples the plan consumes, how many design variants you want covered and whether your customer wants the work done by a particular body. Turnaround is quoted in weeks and shifts with queue length, so ask for this month's figure rather than the one printed on a website. Book the slot before your production run, not after it. Ask which accreditation the laboratory holds and for which test methods, since scope varies between them.

## What this guide is built on

The transport requirement and the 30% ceiling for air freight of lithium-ion were taken from secondary summaries. The manual itself was not opened while writing this page and the test list above carries the same caveat. Before you scope a test plan or write a shipping instruction, read the current text and speak to a dangerous goods adviser about your own route and packaging.