Battery Testing Methods · Last reviewed 2026-09-16
A battery can read a full resting voltage while failing to deliver current — the voltage says the tank is full, but the load test proves whether the pump works. For a starting battery, delivery is the entire job, which is why the load test is the classic shop-floor decision-maker (see voltage chart for the resting-only read).
| Item | Value |
|---|---|
| Load | ~½ of the CCA rating |
| Duration | ~15 seconds |
| Reference temperature | ~21°C (temperature-corrected) |
| Pass voltage | ≥ ~9.6V at 21°C |
| Below ~9.6V | Failed — weak or discharged battery |
The pass threshold drops with temperature — the colder the battery, the lower the acceptable floor, which is why the test corrects for temperature before judging.
A load test measures delivery, not capacity: a battery can pass the 15-second load yet hold little energy. For endurance answers use capacity testing; for a fast health proxy use conductance. The three tests answer different questions, and a serious evaluation uses all three.
My read: The load test is the test that answers the question people actually care about — will it start? — and it deserves its place as the final word after the quicker proxies have flagged a suspect battery.
Why I think so: Voltage, conductance and CCA estimates are proxies; the load test is the delivery itself. When the proxies disagree with the load test, the load test wins — which is why it remains the shop-floor standard despite the newer electronics.
My view as an editor, not a purchasing guarantee.
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