UN38.3 is the UN test certificate that proves a lithium battery design has passed vibration, shock, thermal, and short-circuit tests. Every model of battery you ship needs one, and the test report has to match the exact model number on the label.
MSDS, or Material Safety Data Sheet, lists the chemical composition, handling instructions, and emergency response steps. Shipping lines and customs will ask for it at the port of loading and the port of discharge. Without both documents, your container sits.
The cost is modest. A UN38.3 test report from a Chinese lab costs around $2,000 to $4,000 per model and takes 4 to 6 weeks. An MSDS is essentially free — most factories have them ready.
The cost of not having them is brutal. We have seen containers held at Lagos port for three weeks waiting on an MSDS that did not match the new model number the factory had quietly switched to. Demurrage ran into five figures. Customs does not negotiate.
Two things to check before you ship. First, the UN38.3 report must be issued by a recognised lab and signed by a real engineer, not a stamp-and-sell outfit. Second, the MSDS must list the same cell model and configuration as what is physically on the container. A 100 Ah LiFePO4 with a 100 Ah MSDS is fine. A 100 Ah label with a 90 Ah MSDS is a five-week hold.
If you are buying through a trading agent, ask them upfront for both documents before you pay the deposit. Any agent that says "we will sort it later" is about to cost you real money.