Ford Focus Mk3 Battery: Specs, Fitment & Common Faults

Confirmed OEM battery references for the Mk3, and why stop-start disabling itself doesn't automatically mean the battery has failed.

Generation covered: this guide is for the third-generation Focus, built 2011–2018 (commonly the 2014–2018 registered examples still in daily use). The newer Mk4 Focus (2018–) uses different part numbers throughout — check your V5C logbook or VIN if you're unsure which generation you have.

Illustration for editorial purposes

The Part Everyone Blames First, Not Always Correctly

A car that won't start gets blamed on the battery more often than any other component, and it's right often enough to make that assumption a reasonable first check. But it's not always the actual cause, which is worth knowing before spending money on a replacement that doesn't fix anything.

Before you buy: battery size, capacity and type (standard vs AGM/EFB for stop-start systems) vary by trim and engine. Always confirm against your VIN before ordering.

OEM Part Numbers & Sizes

Accuracy note: battery specification on the Mk3 Focus depends heavily on engine, trim, and whether the car has Ford's stop-start system — always confirm your existing battery's size and Ah rating (printed on the case) before ordering, rather than relying on part number alone.

Common OEM cross-reference	Ford 000915105DA, 13502901, 282915105 (widely used group across several petrol and diesel variants)
Typical case dimensions	Length 207–317mm, width 175mm, height 175–190mm (varies by spec — measure your existing battery)
Stop-start equipped cars	Require an AGM or EFB battery, not a standard flooded-cell replacement — fitting the wrong type can damage the stop-start system

Because Ford fitted several different battery capacities across the Mk3's production run — depending on engine, trim, and whether stop-start is fitted — the safest way to order the right one is by the Ah rating and case size printed on your current battery, cross-checked against your VIN, rather than assuming a single part number covers every car.

What It Does

The 12V battery provides the power needed to start the engine and runs electrical systems when the engine isn't turning. On cars with stop-start technology, the battery works much harder than on older designs, since the engine switches off and restarts far more frequently — which is exactly why these cars need a specific AGM or EFB battery type rather than a standard unit.

Warning Signs, DIY Difficulty & Aftermarket Advice

These are the same regardless of make or model — see our full Battery Guide for warning signs to watch for, confirming fitment against your VIN, and matching the right technology (standard, EFB, AGM) when buying aftermarket.

More Ford Battery

The same part, covered across other Ford models.

Ford Focus Mk3 Battery: Specs, Fitment & Common Faults

The Part Everyone Blames First, Not Always Correctly

OEM Part Numbers & Sizes

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