Conductance vs Load Test

Battery Testing Methods · Last reviewed 2026-09-16

Direct answer: The conductance tester sends a small AC signal and estimates CCA from how well the battery conducts — fast, non-destructive, works on a partially charged battery. The load test draws a real current (about half CCA for 15 seconds) and watches the voltage — slower, more demanding, definitive. Conductance screens; the load test verdicts.

The comparison

	Conductance	Load test
Signal	Small AC injection	Real DC load (½ CCA, 15 s)
Speed	Seconds	~15+ seconds plus setup
Battery stress	None	Real — needs decent charge first
Answer	Estimated CCA (health proxy)	Direct delivery verdict
Best for	Screening, partial charge	Final verdict, warranty

When each wins

Conductance wins where speed and gentleness matter — fleet screening, batteries at any state of charge, the modern shop floor. The load test wins where the verdict must be final — warranty decisions and disputed diagnoses — because it measures the actual delivery, not a correlate (see load testing and conductance). They agree on healthy batteries; the disagreement cases are where the load test's directness matters.

Why This Matters

Where I stand: Conductance vs load test is proxy vs ground truth — the electronic tester is the better screening tool, the load test is the better court — and a serious diagnosis uses the fast tool first and the direct one when the answer matters.

The reasoning: The AC tester correlates with delivery; the load test is delivery. When they agree, either suffices; when they disagree, the direct measurement wins. Knowing which question is being asked — screen or verdict — is how the two tools are used correctly.

This is my analysis, not a verified fact or purchasing guarantee.

Sources

Tester-manufacturer documentation — conductance and load test procedures.
BCI / SAE references — load test thresholds and conductance correlation.

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