Five Years of Customs Records for Every Battery Pack You Import

A US importer of lithium-ion battery packs must keep the entry records for five years from the date of entry, and for a battery pack that file is bigger than most people expect. The commercial invoice, packing list, and entry summary are the floor. Above that sit the UN 38.3 test summary for the cell and the pack, the shipper's declaration for dangerous goods, and the state-of-charge documentation that traveled with that particular shipment. The obligation belongs to the importer of record whether or not a broker filed the entry, it runs whether or not a dollar of duty was owed, and it only counts if the documents can actually be produced when they are requested.

The email does not use the word "audit." Mine came in as a Request for Information, with an entry number in the subject line, a numbered list in the body, and a response date eleven days out. No lawyer, no subpoena. A person at the port asking for documents.

I remember opening the shared drive and feeling fine for about ninety seconds. The folder was named after the purchase order, not the entry, because that is how it got created the morning the first shipment was booked. Inside were the invoice, the packing list, the bill of lading, and the entry summary the broker had emailed over after clearance. Four of the nine items on the list, found in a minute and a half. Then I hit item six, "UN 38.3 test summary for cell and pack," and started opening PDFs I had not opened in two years.

That moment is the reason this article exists. Everything below is what was actually in that folder, what was missing from it, and what I changed afterward.

The letter is not the document

The first thing I pulled up was a one-page PDF on supplier letterhead. It said the product "complies with UN 38.3" and "meets the requirements of the UN Manual of Tests and Criteria." I had filed that under compliance and never thought about it again.

It is not a test summary. It is a statement of opinion from the seller. The UN 38.3 test summary is a specific document built to a defined content list in the transport regulations: who manufactured the cell, who manufactured the pack, a description of each, the tests that were run, the results, and the date. It exists so that a carrier, a forwarder, or an inspector can see which tests were performed and what came back, without reading the full laboratory report.

When someone from CBP asks for the test summary, they are asking for that document. If all you can hand over is a letter that says "trust us," you have not answered the request, and the person on the other end knows the difference immediately.

The broker's copy is not your copy

This is the part that catches people who did everything else right. The broker filed the entry, so it feels like the broker holds the paperwork. The broker does keep records, but it keeps them for its own liability, organized around its own entry numbering, and it is not going to have your UN 38.3 summary, your dangerous goods declaration, or the state-of-charge statement the forwarder attached to the air waybill.

Under the recordkeeping rules, the importer of record is the party with the five-year obligation. Five years from the date of entry, no matter who keyed the data into ACE. So "our broker has it" is not a comfortable sentence to type on day eight of an eleven-day deadline, and it stops being true entirely once your account moves. Brokers get acquired. Portals get retired. The person who handled your entries for six years takes another job, and the institutional memory goes with them.

Your copy is the only copy you control. That was the sentence I wrote at the top of the internal note after that week.

Duty-free entries still generate a file

I have watched someone argue that a shipment with no duty owed has nothing to look at. It does not work that way. The five-year clock starts at the date of entry and runs the same for a duty-paid shipment, a free trade agreement claim, a warranty replacement, and a low-value entry that still required formal or informal entry paperwork.

CBP is not checking whether you owed money. It is checking whether the entry was accurate: the classification, the declared value, the country of origin, and whether the batteries were declared correctly as dangerous goods. Duty-free shipments are exactly where the file tends to be thinnest, because nobody felt a reason to keep anything. Same retention, no exceptions for good news.

The battery documents are the ones that disappear

General entry paperwork has a habit of surviving. It comes from your own accounting system, it goes through your broker, and it lands in a folder because somebody needed it to pay an invoice.

The battery documents come from somewhere else entirely, and each one comes from a different desk.

The UN 38.3 test summary comes from the cell maker or the pack assembler, often months before your purchase order exists, often reissued when the model changes, and almost never sent proactively.

The shipper's declaration for dangerous goods comes from whoever prepared that specific shipment. It is tied to a flight, a date, a consignee, and quantities. It is not a template you can recreate later, because the details that matter are the details of that shipment.

The state-of-charge documentation is the one people forget completely. Cells and batteries shipped by air have to be at a limited state of charge, not more than 30 percent, and the shipper is supposed to be able to show what was done. If you only ever received one line in a shipping email saying "shipped at 30% SOC," that line is your record, and it is sitting in the mailbox of someone who left the company.

I keep all three of these, plus the air waybill or bill of lading they traveled with, in the same folder as the entry. Not because a rule says those exact items have to be adjacent, but because when a request arrives you will be pulling them in one pass, and you will not want to be reconstructing which declaration went with which shipment.

Get the test documents at the purchase order, not later

There is a reason to ask for the UN 38.3 summary and the underlying test report when you place the order, and it has nothing to do with customs at that moment.

CBP can also request records from the seller or the manufacturer. If the manufacturer has a clean archive, you are fine. If the cell model was discontinued, if the assembler was acquired, if the test lab's archive is searchable only by the lab's own job number rather than your part number, that path gets slow and stays slow.

At the purchase order stage you have leverage. The sales engineer is answering your emails, the test report exists in someone's active folder, and the model is still in production. Three years later you are a stranger asking a successor company for a document about a product they no longer build. I now treat the UN 38.3 summary as a line item that has to be received before the first shipment clears, alongside the packing list.

Electronic is fine. Retrievable is the word that matters.

Records can be kept electronically, which almost everyone does. The two conditions that get tested in practice are legible and retrievable.

Legible: a packaging list scanned at low resolution on a thermal printer comes back as a gray rectangle. If the officer cannot read the quantity and the description, having the file does not help you.

Retrievable: if the answer to a document request is "give us a few weeks and we'll dig through the archive," the records exist in a technical sense and not in any sense that matters.

What I built after that first request was deliberately boring. One folder per entry, named with the entry number first and the purchase order second, so it can be found by either. Inside, the same document types in the same order every time: entry summary, invoice, packing list, bill of lading or air waybill, classification and origin support, then the battery set. Plus a one-page index at the top listing what is in the folder and what is missing, with the date each item was received.

That index is the piece most people skip, and it is the piece that saves you. It means the file can be answered from by someone other than the person who assembled it. If the whole thing lives in one person's head, you have a single point of failure with a five-year service life.

What the request looks like in practice

The list is specific. It names the entry, the line items, and the document types. It usually gives you a portal or an email address to send to, and a format to send in.

Three things I have learned to do on the way in.

Read the list against your index before you touch anything, and mark which items you have, which you have in a weaker form than requested, and which you do not have at all. A single-page letterhead statement where a test summary was asked for is not a category of its own; it is a gap with a partial substitute, and you should know that before you hit send.

Send files that open. A link to a drive the recipient cannot access is not a response. A file that requires software they do not have is not a response. If they asked for one document, send that document rather than a 400-page archive dump, because a reviewer who has to hunt is a reviewer who comes back with more questions.

And if something genuinely does not exist, the honest answer with a date attached is worth more than a guess. I have never seen a fabricated document improve a situation. I have seen a missing document handled cleanly when it was disclosed early rather than discovered late.

The reset point

The reason all of this is worth writing down is that the five-year clock never stops. Every entry you clear this month starts a new five-year window. If you fixed the file for the entries under review and went back to the old habits, you have not fixed anything. You have bought time on one request.

The change that actually holds is smaller than a system. It is one folder per entry, created when the entry is created. It is the three battery documents requested at the purchase order stage, not after clearance. It is an index anyone on the team can read. And it is a calendar reminder, or whatever you use, that the file stays where it is until five years from the date of entry, whether the shipment was dutiable or not.

I still do not know exactly which entry the next request will name. I know I will not be opening PDFs I have not touched in two years to find out.