The battery hub
An estimated 70–100 million car batteries are sold in the US every year (industry estimate), and batteries die in waves — the first cold snaps of fall, the January deep freeze, when failure reports run about 15% above the autumn baseline. Every one of those deaths inside a warranty window is a counter conversation. This hub is the map: the windows, the math, the clocks, and the traps, chain by chain.
| Chain | The battery position — as published |
|---|---|
| AutoZone | Free replacement by line: ProPower 1 yr · ProPower Plus 2 yrs · Ultra / AGM / Duralast Gold 3 yrs. Then proration by the published formula (remaining ÷ total) × price. A replacement battery's warranty runs from the ORIGINAL purchase date. |
| Advance | General rule: 45 days or the longer period printed on your receipt — the original receipt or order invoice is the proof the longer period stands on. |
| O'Reilly | Original receipt demanded; §1.1 national database behind it. §2 traps: a discharged-but-rechargeable battery is NOT covered; within 25 miles you must return to the purchase store, beyond it call Warranty Administration (1-866-830-4351) first. |
| NAPA | Per-line terms; the claim runs through the store's Alleged Defective Merchandise Tag to an examiner. Claims within 30 days of discovering the defect. Labor never included. |
Sources: each chain's published warranty documents, checked Oct 20, 2026; details and cell-by-cell sourcing on the chain pages. Battery volume: estimate, labeled as such — no exact national count is published.
The exchange-count question — and the cap that isn't in the text. The AutoZone answer →
The formula is published. The counter's number should equal it. Work the math →
The database behind the receipt wall, and the reconstruction kit. The O'Reilly play →
Voltage at rest is not capacity under load. The dispute play →
Two sister sites live on the calculation side of this same garage. RaceCombo runs the racing and tuning calculators — gearing, tire size, bracket math. RegearReady works out regear decisions for Jeeps and trucks — which ratio, what it does to RPM and the speedometer. Free tools, same house.
Not sure which wall you hit? The free checker sorts it in a few picks — chain, part, purchase date, your proof, and the store's own words — and gives you where you stand under the written policy, the proration math where it applies, the exact next counter move, and the ladder above the store. Run the checker →
One payment, yours to keep. You do every step yourself — at the store, on the phone, in writing; we never call a store for you. See everything inside the kit →