Before committing to large orders, buyers should conduct rigorous sample testing using this protocol:
- Equipment: Use a battery analyzer with 4-wire measurement, thermal camera/thermocouples, calibrated IR meter (AC 1 kHz and/or DC method), precision scale, calipers, and safety fixtures.
- Capacity Test: Fully charge cells per the datasheet, rest for 60–120 minutes, then discharge at 0.2C to the cut-off voltage (e.g., 2.5V). Repeat at your application’s actual discharge rate (e.g., 1C). Record energy (Wh) and capacity (Ah).
- IR Test: Measure DC pulse or AC 1 kHz IR at 25°C after standardized rest. Compare against datasheet limits; tight distributions indicate grade-A cells.
- Thermal Profile: Monitor temperature rise during continuous load tests. Flag cells that exceed your safety envelope.
- Cycle-Life Spot Check: Even 100 cycles at your DoD can reveal early degradation patterns.
Acceptance Criteria: Define thresholds for capacity (≥95% of rated), IR (≤ datasheet limit), temperature rise, and distribution tightness. Reject lots failing any criterion.
This testing minimizes risks of field failures and ensures cells meet your performance expectations.
This answer is sourced from Posts《8-step checklist to buy genuine 18650 3.7V 2600mAh Li-ion cells》