Almost every battery supplier will send you a UN38.3 report within an hour of asking. Very few buyers open it. The report is treated as a box to tick, which is exactly why a forwarded PDF from a different model passes as evidence so often.
This is a short guide to reading one properly. It takes about ten minutes and it will tell you more about a supplier than a factory tour.
What UN38.3 actually is
UN38.3 is section 38.3 of the UN Manual of Tests and Criteria. It is a transport test, not a performance test and not a product certification. Its purpose is to establish that a lithium battery can survive the mechanical and electrical conditions of air, sea and road transport without becoming dangerous.
Every lithium battery shipped commercially needs it. Airlines will not take the cargo without it, and freight forwarders will not book the space. That is the whole scope. It says nothing about cycle life, nothing about grid compliance, and nothing about CE.
The eight tests
| Test | What it simulates | Pass condition |
|---|---|---|
| T1 Altitude simulation | Low pressure in an unpressurised cargo hold, 11.6 kPa | No leakage, no venting, no disassembly, no fire |
| T2 Thermal test | Repeated cycling between 72 °C and −40 °C | No leakage, no venting, no disassembly, no fire, and six hours later still no fire |
| T3 Vibration | Transport vibration, sinusoidal sweep | Same, plus no loss of voltage |
| T4 Shock | Handling and transfer impacts | Same |
| T5 External short circuit | Terminals bridged at 57 °C | Case temperature does not exceed 170 °C, no disassembly, no fire |
| T6 Impact / crush | Mechanical damage to the cell | No disassembly, no fire |
| T7 Overcharge | Charging beyond rated voltage | No disassembly, no fire, seven days later still no fire |
| T8 Forced discharge | Forced discharge through the cell | No disassembly, no fire, and open circuit voltage at least 90% of pre-test |
A complete report lists all eight with conditions and results. If a supplier sends you a page that says “UN38.3: passed”, you have been sent a conclusion, not a report.
Check 1 — does the report name your configuration
This is the one that catches most buyers. UN38.3 is issued to a specific battery design: chemistry, cell model, capacity, voltage, and physical assembly. A report for a 51.2 V / 314 Ah unit at 16 kWh does not automatically cover a 32 kWh cabinet built from the same cells. Different assembly, different mass, different thermal behaviour under T2, potentially different outcome.
Open the report and find the sample description page. It should state the model, the rated energy, the weight and the cell chemistry. Then compare those numbers to the quotation you are about to sign. If the weight differs by 30%, you are holding a report for a different product.
This is not a technicality. Customs and carriers check the report against the shipment. A mismatch is a delay at the port, at your cost.
Check 2 — summary or full report
Both exist and both are legitimate, but they are not the same document. The test summary is typically one or two pages: report number, sample description, the eight tests, pass or fail. The full report runs ten to twenty pages and includes test conditions, chamber settings, measurement data, photographs of the sample before and after, and the signatory.
A summary is enough for a freight booking. A full report is what you want when a customer, an insurer or a regulator asks you to prove the goods are what you said they were. Ask which one you are being sent, and ask for the other one before you need it.
Check 3 — is it still valid for the current design
UN38.3 does not carry an expiry date in the way a certificate does, but it becomes invalid when the design changes. Cell supplier change, BMS change, enclosure change, or a different module arrangement can all invalidate the original test basis. The report date tells you when the design it describes was tested.
Practical rule: if the report is more than about three years old and the supplier has changed cell supplier in that period, ask for a statement that the tested design is still the shipping design. If they cannot give you one in writing, treat the report as historical.
Check 4 — can you verify it without asking the supplier
A report you cannot verify is a PDF. Three things make verification possible:
- The test house name, not just a logo. A named laboratory can be called.
- The report number, in the format the lab uses. Report numbers are sequential and traceable.
- An accreditation mark — CNAS, ilac-MRA or the local equivalent — tied to a registration number you can look up.
With those three, you can call the laboratory and ask whether report ORT261014112214-R01 exists and what sample it covers. That takes one phone call and settles the question permanently.
If a supplier has redacted the laboratory name as well as their own, you cannot verify anything. Redacting the commissioning party is reasonable — it protects their customer list. Redacting the test house is not.
What UN38.3 does not cover
| Question | Answered by UN38.3? | What actually answers it |
|---|---|---|
| Can this be shipped by air, sea, road? | Yes | UN38.3 plus the transport classification |
| Is it safe in normal use? | No | IEC 62619, UL 1973 |
| Can it connect to the grid? | No | Grid code certification, per country |
| Can I put it in a building? | No | UL 9540A, fire code, local approval |
| Can I sell it in the EU? | No | CE marking, which is a separate declaration |
Suppliers blur this line constantly, usually by presenting “UN38.3 certified” as if it were a product certification. It is a transport document. Useful, necessary, and narrow.
How we handle it
We publish the full set for the 51.2 V / 314 Ah unit — UN38.3 summary and full report, MSDS, dangerous goods classification, sea freight and road transport conditions — at Certificates and Test Reports. No form, no email gate. The commissioning party is redacted; the test house, the report number, the dates and every result are visible.
Those six documents name the 16.08 kWh unit. If you are quoting another model in the range, ask us for the report that names that configuration. If it has not been issued yet, we will tell you that instead of forwarding this set and letting you assume it transfers.
That is a lower offer than most suppliers make. It is also the only one you can check.