Battery Testing Methods · Last reviewed 2026-09-16
| Item | Detail |
|---|---|
| Method | Rest the charged battery, track voltage/capacity over days-weeks |
| Normal (lead-acid, ~25°C) | A few % per month |
| Accelerated screening | Higher temperature shortens the test |
| Fast failure | Internal short, metallic contamination, sulfation |
Self-discharge decides shelf life — how long a battery survives in storage before it sulfates or drains itself (see date codes and sulfation). It also screens quality: in manufacturing, cells with abnormally high self-discharge are the ones hiding defects, which is why the test is a standard sorting gate after formation.
A battery that drains several percent per week instead of per month is failing, not resting. The reading separates three conditions: normal (slow, chemistry-limited), high (aging or partial shorts), and catastrophic (internal short — lithium packs in particular must be quarantined at this point).
Where I stand: Self-discharge is the quietest diagnostic in batteries — nothing visibly happens, which is exactly why the test matters: it catches the failures that declare themselves only after weeks on a shelf or a year in a drawer.
Why I think so: The test reads the battery's internal leaks of charge — the earliest signature of shorts and contamination. For manufacturers it sorts defects; for buyers it explains why shelf-fresh matters; for everyone it is the difference between a battery that rests and one that dies quietly.
This is the author's editorial view, not a purchasing guarantee.
Return to Battery Testing Methods · World Battery Hub. Informational, not purchasing advice.