Audi A4 Battery: Specs, Fitment & Common Faults

On the A4, a persistent drain has genuinely been traced to the dash control panel unit on related models, not an electrical short.

Illustration for editorial purposes

OEM Part Number: 760-850A

Genuinely useful to know: Audi's current genuine battery part numbers follow a consistent pattern — 000915105 followed by a two-letter suffix that encodes the exact capacity and technology (e.g. "CE" = 92Ah AGM, "EE" = 93Ah EFB, "CF" = 105Ah AGM). Checking the suffix on your existing battery's label is a reliable way to confirm the exact replacement, since A4 has used several genuine capacities.

Standard AGM fitment	92Ah AGM, 760-850A (EN) — suffix "CE"
Higher-demand variants (S4/S-Line, larger diesel)	105Ah AGM — suffix "CF"
Genuine part number format	000915105 + two-letter suffix — confirm the exact suffix via your existing battery's label or VIN

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.

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.

A Genuinely Useful Piece of Context Worth Knowing About Persistent Drains

If the battery keeps going flat despite everything appearing switched off, this is genuinely worth knowing: documented cases on related Audi models describe a persistent drain traced to the dash control panel unit itself rather than an electrical short or failing alternator, with replacing this specific component resolving the drain entirely.

A genuinely important finding worth knowing about the 48V mild hybrid system: alternator failure related to this system has been confirmed in the US with a seven-year extended warranty, though UK owners have found it difficult to get equivalent support from Audi UK for the same fault.

It's also genuinely worth knowing a useful diagnostic reading: a healthy trickle charge to the alarm typically measures around 0.03 amps, with anything notably higher pointing toward a genuine parasitic drain.

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 Audi Battery

The same part, covered across other Audi models.