Battery Testing Methods · Last reviewed 2026-09-16
| C-rate | For a 100 Ah cell | Time |
|---|---|---|
| 1C | 100 A | ~1 hour |
| 2C | 200 A | ~30 min |
| 3C | 300 A | ~20 min |
A 0.5C charge takes ~2 hours; the C-rate scales current inversely with time.
The C-rate is the bridge between the datasheet and the application: an EV cell must sustain multi-C discharge for acceleration and multi-C charge for fast charging, while a storage cell may never exceed 0.5C. The test verifies what the chemistry can actually deliver — including the heat it generates at high rates (see temperature testing and C-rate fundamentals).
The same battery delivers less capacity at higher rates — a cell rated 100 Ah at 0.5C may give ~95 Ah at 2C, with the gap widening as the rate rises. The rate-capacity relationship is part of the specification, not a defect: it reflects the internal losses that grow with current (see C20/C10/C5 for the lead-acid version of the same physics).
My position: The C-rate is where a battery's application claim is verified — the datasheet promises capacity, but only the rate test proves what the battery can actually deliver when the job demands it fast.
What drives this: Every demanding application is a rate application. The buyer who checks sustained C-rate — and the capacity at that rate — is verifying the real product, not the gentle-rate headline number.
This is the author's editorial view, not a purchasing guarantee.
Return to Battery Testing Methods · World Battery Hub. Informational, not purchasing advice.