Common pitfalls when sourcing 18650 cells include:
- Rewrapped or “Mystery Brand” Cells: Counterfeiters often rewrap low-grade cells as premium models. Fix: Insist on traceability and test samples for weight, IR, and capacity consistency.
- Grade B Bargains: Off-spec cells may pass basic tests but fail prematurely. Fix: Specify Grade A cells with written grading criteria; derate performance expectations for Grade B.
- Protected/Unprotected Mismatch: Using protected cells in BMS-managed packs can cause conflicts. Fix: Reserve protected cells for single-cell devices; use unprotected cells in packs.
- Top-Style Mismatch: Button-top cells may not fit flat-top designs. Fix: Validate mechanical specs early and order the correct top style.
- Shipping Non-Compliance: Carrier rejections due to incorrect UN3480/UN3481 classification or missing documentation. Fix: Follow IATA DGR and 49 CFR 173.185 rules, maintain UN38.3 summaries, and use proper labels.
- Overstated Performance: Capacity rated at 0.2C may not hold at higher loads. Fix: Test cells under real-world conditions.
Proactive measures like supplier audits, sample testing, and contract safeguards mitigate these risks.
This answer is sourced from Posts《8-step checklist to buy genuine 18650 3.7V 2600mAh Li-ion cells》