CCA Testing: How Cold Cranking Amps Are Measured

Battery Testing Methods · Last reviewed 2026-09-15

Direct answer: A true CCA test chills a fully-charged battery to the standard's temperature, then discharges it at a constant current for a set time while watching that the voltage stays above a cut-off. Under SAE J537 that is −18°C for 30 seconds at or above 7.2 V. The CCA rating is the current the battery can sustain under those conditions.

The cold-chamber test (SAE J537)

Fully charge the battery, then chill it to −18°C (0°F) and hold it there.
Discharge at a constant current for 30 seconds.
The battery passes if its voltage stays at or above 7.2 V (1.2 V per cell) for the full 30 seconds.
The rating is the current at which it just passes.

Why the number depends on the standard

Standard	Temperature	Cut-off / method
JIS D5301	−15°C	reference (warmer → higher number)
SAE J537	−18°C (0°F)	30 s, ≥7.2V
EN 50342	−18°C	10 s to 7.5V
DIN 43539	−18°C	30 s to 9.0V

A warmer test or a lower cut-off prints a higher number for the same battery. A JIS value (tested at −15°C) reads higher than an EN/SAE value (tested at −18°C) — they are not comparable. See the main-site CCA article for the full explanation.

Conductance testers estimate — they do not load-test

Workshop conductance testers measure the battery's internal resistance/conductance and estimate CCA from it. They are fast and non-destructive, but they are not a 30-second cold-chamber discharge. Two things follow:

An estimate is only meaningful against a nominal CCA that used the same standard.
A measured CCA that drops far below nominal over time signals ageing — even though the absolute number is an estimate.

The Author's Take

Position: The most important thing a CCA test result must tell you is the standard, not just the number — a tester set to the wrong basis will "pass" or "fail" the same battery differently.

Reasoning: JIS and SAE differ by 3°C and a cut-off voltage, which is enough to move the printed value. If the test report does not name the basis, the number is a guess, not a measurement.

This is the author's editorial view, not a purchasing guarantee.

Sources

SAE J537 — cold cranking test method (−18°C, 30 s, 7.2V).
EN 50342, JIS D5301, DIN 43539 — standard variants.
Conductance-tester documentation (manufacturer manuals) — estimation vs load-test distinction.

Return to Battery Testing Methods · World Battery Hub. Informational, not purchasing advice.