Due diligence is how a device brand confirms that a charger supplier can actually do what the program needs: produce evidence, hold the process and behave like a partner across orders. The diligence runs from documents to the engineering team to the site, and every step produces a record. This guide covers capability evidence beyond the brochure, quality systems and test flow, interviewing the engineering team, site visit essentials, and the signals that remove a candidate.
Key takeaways
- Due diligence is a document review plus a people and site check.
- The engineering team interview reveals how the supplier thinks, not just what it sells.
- The signals that remove a candidate are visible before the order.
Content updated: August 2026 — confirm current standards editions and model-specific details before ordering.
Scope note: This guide is industry information, not regulatory, legal or certification advice; the diligence approach is general industry practice.
Capability Evidence Beyond the Brochure
The brochure states the supplier's story; the evidence states its capability. The diligence starts by asking for the document set: certificates, test reports, quality system descriptions and batch record samples. Each item is checked against the configuration the program needs.
The evidence review follows the model-match rule from the rest of the cluster. The certificate must name the exact configuration and standard edition, the report must cover the same model, and the batch records must exist for actual shipments. Evidence that names a similar product is context, not proof.
The capability question is also directional: what can this supplier do for this program, not what has it done in general? The evidence is reviewed against the program's device list, markets and documents, and the fit is scored the same way for every candidate.
The evidence review also checks dates. Standards are revised, certificates are refreshed and batch records age, so the diligence records when each item was reviewed and which edition it cites. A dated evidence file is the program's audit-ready record; an undated one is a snapshot without context.
The capability review is also where the program's own requirements are tested. If the required documents do not exist for the configuration, the candidate is not capable for this program, regardless of its general standing. The review is per configuration, not per supplier.
Quality Systems and Test Flow
The quality system and the test flow describe how the factory operates. The diligence asks which systems are certified, which tests run in production and how the records are kept, and it verifies the answers with documents and site evidence.
The useful checks:
- Which quality standards does the factory hold, and what do the records show?
- Which tests run on every unit, and which run on samples?
- What does the aging test cover, and for how long?
- How are failures recorded, and how do they feed correction?
The answers, with records, describe the operating reality. A factory that tests every unit and keeps the records is running the process; one that describes it without records is running a presentation.
The quality system review should also include the failure side. How are rejected batches handled, how are field complaints reviewed and how do corrections feed back into the process? The failure story reveals the system's real shape, and it is reviewed with the same rigor as the success story.
The test flow is also the basis for the batch record expectation. The tests the factory runs in production are the tests the batch records document, and the diligence confirms that the two match. A factory that describes more testing than its records show has a gap between its story and its operation.
Interviewing the Engineering Team
The engineering interview reveals how the supplier thinks about the program. The questions go beyond the sales deck to the people who would actually run the project: how they approach the device profile, the thermal design, the change process and the documentation.
The interview is also a signal of depth. A team that answers technical questions with specifics — test conditions, failure modes, certification mechanics — has engineering substance; one that answers with marketing language does not. The depth of the answers predicts the depth of the program.
The interview should include the same questions asked to every candidate, so the answers are comparable. The notes are filed with the other diligence records, and the comparison is a decision rather than a first impression.
The interview also tests how the team would handle the program's specifics: the duty cycle, the environment and the document set. A team that asks for the device profile before discussing hardware is running the right process; one that sells first and asks later is running a sales conversation.
The engineering interview is also the moment to test change management. Ask how the team would handle a component substitution or a market addition, and the answer reveals whether the process exists. The interview predicts the program's change behavior better than the brochure predicts its quality.
Site Visit and Audit Essentials
The site visit verifies what the documents describe. The tour follows the production flow, checks the test equipment and the aging area, and looks at the batch records and the warehouse segregation. The visit is the physical half of the diligence.
The audit essentials:
- The production flow matches the described stages.
- The test equipment exists, is calibrated and is used.
- The batch records match the shipments.
- The warehouse keeps configurations and batches segregated.
The visit also includes the failure story: where failed units are kept, how they are reviewed and what happens after correction. The failure process reveals the system's real shape better than the success story.
The site visit should also cover the records at the point of use. The batch records are reviewed where they are created and stored, not in a presentation folder, and the warehouse check confirms that configurations and batches are segregated. The visit verifies the documents in their operating context.
The visit findings are written up with the evidence and filed with the rest of the diligence. A visit without a written finding is a tour; the finding is what the sourcing decision and the audit read.
Signals That Remove a Candidate
Some signals remove a candidate before the diligence completes:
| Signal | What it means |
|---|---|
| Documents never arrive | The evidence does not exist |
| Certificates name different models | The configuration is not covered |
| Technical questions get marketing answers | The engineering depth is not there |
| Batch records are unavailable | Traceability is not running |
| Change questions are deflected | The process is not controlled |
The signals are the same for every candidate, and the same standard makes the shortlist fair. A candidate that fails a signal has not failed a preference; it has failed the evidence standard.
The diligence record is the deliverable. The documents, the interview notes and the visit findings are filed, and the record supports the sourcing decision and the audit. A diligence run with a record is a program; one run without it is a tour.
The diligence record also feeds the reorder review. The same evidence standard that qualified the supplier at the start is applied at each reorder, so the relationship stays on the standard rather than drifting. The record is the baseline, and the reorders are the checkpoints.
The diligence closes with the same discipline as the rest of the cluster: the evidence names the configuration, the process is verified in practice and the record is kept current. A device brand that runs the diligence this way has qualified a partner, not just found a factory — and the qualification is the difference between a program and a purchase.
For the brand starting the process, the first step is small: write down the program's requirement — device, markets, documents — and send the same evidence request to every candidate. The response set, the interview notes and the visit findings then fall into place, and the comparison is a decision rather than a first impression. The diligence is a process, and every program benefits from running it the same way.
Due diligence starts with the WECENT website for the company and platform background, then moves to the Factory page for the manufacturing and quality context and the Quality Control page for the production test flow and records. To run the diligence for a candidate configuration, request the evidence set from WECENT's project engineering team — the review returns the certificates, test flow description and batch record approach for the program.
Frequently Asked Questions
What is the first document to request in due diligence?
The certificate for the exact configuration, with the test report behind it. The model-match rule — documents naming the precise SKU and standard edition — is the starting evidence.
Why interview the engineering team?
Because the interview reveals how the supplier thinks about the program. Technical specifics predict engineering depth; marketing language predicts a sales-led relationship.
Is a site visit required?
For a healthcare-adjacent program, yes, or a detailed remote audit. The production flow and test equipment are verified in practice, not from the brochure.
What signal should remove a candidate immediately?
Documents that never arrive, or certificates naming different models. Those are evidence failures, not fixable gaps.
How do I compare candidates fairly?
Ask the same questions, request the same documents and score the same signals for every candidate. The same standard makes the comparison a decision.