Comment valider un échantillon de batterie externe avant la production en série : liste de contrôle pour les acheteurs
Short answer: approve a defined product, not a message that says “looks good.” Record the model, battery cell, BOM revision, PCBA, firmware, charging profiles, enclosure, colour, logo, labels, accessories and packaging. Sign and date at least two matching reference samples. Any later change should return through written approval.
A sample can perform well and still be a poor production reference if nobody records what is inside it. The factory may later use a different cell, connector, cable or firmware while keeping the same housing. The finished units can look identical but charge differently, run hotter or require different compliance evidence.
The process below helps importers, private-label brands and sourcing teams turn a final OEM sample into a controlled production baseline. Detailed electrical methods are covered separately in the power bank quality-testing checklist.
What does power bank sample approval mean?
Sample approval means the buyer accepts a specific configuration as the reference for mass production. Appearance is only one part of that decision. Link the approved unit to its written specification, test record, artwork set and packaging version.
The approved sample is often called a golden sample or sealed sample. A pre-production sample can become the golden sample when it uses the final materials and configuration. A stock sample normally cannot, because it may use another logo, cell, firmware or package.
The purchase order should identify the approved sample and the controlling documents. If the sample conflicts with the specification, resolve the conflict before production. “Follow the sample” is too vague when the difference is inside the product.
Four sample stages and what each one can approve
| Sample stage | Main purpose | What it should not approve |
|---|---|---|
| Stock sample | Check the general size, layout, functions and finish of an existing platform | Final branding, packaging or an unverified internal configuration |
| Appearance sample | Approve colour, texture, logo position and visible workmanship | Electrical performance when the internal hardware is not final |
| Engineering sample | Verify changed hardware, firmware, cable, display, magnet or enclosure | Mass-production workmanship before the process is fixed |
| Pre-production sample | Confirm the final product, artwork, accessories and packaging before the production run | Future component substitutions or unrecorded revisions |
Ask the supplier to state which stage each sample represents. A common sourcing mistake is to approve the appearance of a stock sample and assume that every internal detail has also been accepted.
Build the approval file before testing the sample
The sample should arrive with enough information to identify it. Put that information in a compact approval file instead of leaving it across a long email chain. The file should contain:
- A product specification with model number, capacity, nominal voltage and watt-hours.
- The approved battery cell maker, cell model and configuration.
- A controlled BOM or a list of components that cannot be substituted without approval.
- PCBA revision, charging-controller information and firmware version.
- Input, output and protocol tables for every port and built-in cable.
- Mechanical drawing, dimensions, weight, material and colour reference.
- Logo, label, manual and packaging artwork with version dates.
- The compliance plan for the exact model and target markets.
- The test report used to approve the sample, including equipment and test conditions.
If the supplier will not disclose a complete BOM, agree on a controlled component list. At minimum, it should identify the cell, PCBA revision, major charging components, ports, cable assembly, protection parts and enclosure material. The aim is change control, not ownership of the supplier’s design.
Power bank sample approval checklist
| No. | Approval point | Evidence to keep |
|---|---|---|
| 1 | Product identity and revision | Model, sample ID, BOM, PCBA and firmware version |
| 2 | Battery cell and rated energy | Cell specification, configuration and Wh calculation |
| 3 | Input and output performance | Port-by-port charging profiles and measured results |
| 4 | Protection and temperature | Test conditions, limits and pass/fail record |
| 5 | Dimensions, weight and material | Drawing, measurements and material reference |
| 6 | Ports, built-in cables and controls | Fit, function and agreed durability checks |
| 7 | Wireless charging and magnets | Alignment, output mode, temperature and compatibility record |
| 8 | Display and indicators | Charging states, accuracy expectations and firmware behaviour |
| 9 | Colour, finish and workmanship | Colour reference, approved photos and defect limits |
| 10 | Logo and printed information | Artwork version, position, size, colour and adhesion result |
| 11 | Labels, manual and packaging | Final artwork, accessories, barcode and carton configuration |
| 12 | Compliance-document match | Model, cell, hardware and market matched to the relevant file |
Use measurable limits wherever possible. “Good colour” is subjective; a named colour reference and an approved physical sample are useful. “Fast charging works” is also incomplete; record the port, voltage, current, power profile, cable and test condition.
Check the internal configuration behind the housing
Two power banks can share an enclosure and product name while using different cells or PCBAs. Photograph the opened engineering sample when appropriate, or ask the factory to provide controlled internal photos. Match visible identifiers to the component list.
Record nominal battery energy in watt-hours as well as milliamp-hours. Confirm the advertised output belongs to the correct port and operating mode. If the product has several outputs, document the power allocation when they are used together. For built-in-cable models, record whether the cable supports input, output or both.
Detailed capacity, efficiency, protocol, thermal and protection checks belong in the test report. The approval record should reference that report rather than replacing it with a one-line pass result.
Approve branding and packaging as controlled files
Logo and packaging mistakes are easier to see than an internal substitution, but they still cause missed launch dates. Approve the editable artwork source, a dated PDF proof and the physical sample. Check logo position, colour, print method, orientation and resistance to normal handling.
Review the product label, retail box, manual, accessories and master carton together. Capacity, watt-hours, model number, input and output ratings must agree across the product and documents. Do not print a certification logo simply because a similar model carries it. Match claims and marks to the final configuration and market. Our power bank compliance guide explains why model matching matters.
How to create a controlled golden sample
- Prepare at least two matching final samples, one for the buyer and one for the factory.
- Assign a unique sample ID and record the product, BOM, PCBA, firmware and artwork revisions.
- Attach a tamper-evident label or seal without covering required product information.
- Have authorised representatives from both sides sign and date the sample record.
- Take clear photos of every side, the ports, labels, accessories and packaging.
- Store the samples in conditions that protect them from damage or unauthorised use.
- Reference the sample ID in the purchase order and final-inspection criteria.
If the buyer uses an inspection company, give the inspector the same specification, photos and sample ID. Sending only a product link leaves too much room for interpretation.
A practical sample approval record
| Record field | What to enter |
|---|---|
| Project and product | Buyer project name, supplier, model and sample ID |
| Configuration | Capacity, Wh, cell, BOM, PCBA and firmware versions |
| Functional baseline | Input, output, protocols, simultaneous-use behaviour and accessories |
| Appearance baseline | Dimensions, weight, material, colour, finish and logo |
| Artwork baseline | Label, manual, retail packaging and carton file versions |
| Supporting evidence | Test report numbers, compliance-file references and approved photos |
| Decision | Approved, approved after listed corrections, or rejected |
| Authorisation | Buyer and supplier names, signatures and dates |
Keep open actions specific. State the file, dimension or result that must change, who is responsible and when evidence is due. Production should not start while a safety, electrical or regulatory issue remains unresolved.
Which changes require a new approval?
Require written notice before the supplier changes any item that can affect safety, performance, compatibility, appearance or compliance. Typical examples include:
- Battery cell maker, model, chemistry, capacity or configuration.
- PCBA layout, charging controller, protection circuit or firmware.
- USB port, built-in cable, connector, magnet, wireless coil or thermal material.
- Enclosure resin, metal part, adhesive, coating, colour or surface process.
- Product label, manual, packaging, accessory or shipping configuration.
- A factory, assembly line or subcontractor named in the approved plan.
The response does not have to be identical for every change. A packaging text correction may need an artwork proof. A new cell or PCBA may require another engineering sample, performance testing and a compliance review. Decide the level of reapproval before accepting the change.
Sample approval is not batch approval
A golden sample defines the target; it does not prove that 2,000 production units match it. The factory still needs incoming inspection, process controls, functional testing and final inspection. A buyer may also arrange a pre-shipment inspection using an agreed sampling plan.
Compare production units with the approved sample, specification and test limits. A cosmetic match is not enough when the cell, PCBA or firmware can change. Our processus de contrôle qualité des batteries externes describes the production-stage checks, while the buyer testing guide covers measured verification before a bulk order is released.
Red flags during sample approval
- The supplier cannot identify the cell, PCBA or firmware used in the sample.
- The sample model differs from the quotation or compliance reports.
- The factory says production will be “similar” but will not define the allowed differences.
- Charging claims are shown on artwork but not verified by a test record.
- The supplier requests approval before the final label or packaging files exist.
- Component substitutions are allowed without buyer notification.
- Only one unlabelled sample exists and nobody keeps a signed reference.
Resolve these points before releasing the purchase order. A red flag does not automatically make the supplier unreliable, but a verbal assurance cannot replace a controlled record. Use the broader power bank factory audit checklist when reviewing the supplier’s legal identity, capacity and quality system.
Fit sample approval into the production schedule
Set dates for sample delivery, buyer feedback, corrections and final approval. Consolidate comments into one list rather than sending unrelated messages from several people. The factory can then revise one controlled version.
Material purchasing and mass production should follow final approval unless the buyer accepts a documented risk. Ordering custom packaging early may save time, but an artwork change can turn it into scrap. Our guide to custom power bank manufacturing lead times shows where sample approval sits in the full OEM schedule.
Frequently asked questions about power bank sample approval
What is a golden sample for a power bank order?
A golden sample is the signed and dated product reference accepted by the buyer and factory. It should be linked to the approved specification, component revisions, artwork and test record used for mass production.
Is a stock sample enough to approve mass production?
Usually not. A stock sample can confirm the general platform, but it may not contain the final cell, firmware, branding, labels or packaging. Approve a pre-production sample that represents the ordered configuration.
How many golden samples should be kept?
Keep at least two matching samples. The buyer and factory should each retain one identified reference. An inspection company may need another sample or a complete photo and specification file.
Can production start with minor sample issues still open?
Only when the remaining actions are written, low risk and do not affect safety, electrical performance or regulatory information. The buyer should approve the corrected evidence before the affected production step begins.
Does approving a sample replace final inspection?
No. Sample approval defines what should be produced. Final inspection checks whether the completed batch matches that reference and the agreed acceptance criteria.
When must a power bank sample be approved again?
Reapproval is normally needed when the cell, PCBA, firmware, charging function, enclosure, cable, magnet, label or packaging changes. The extent of review depends on how the change affects performance, safety and compliance.
Prepare a power bank sample for approval
When contacting YULIDA, provide the target model, electrical requirements, market, branding files, packaging needs and order quantity. These details are used to plan the sample route and identify the documents and tests needed before the product becomes the production reference.
Review our power bank Services OEM/ODM or Contacter YULIDA about a 500, 1,000 or 2,000-piece project.
