Audi A3 Battery: Specs, Fitment & Common Faults
A genuinely distinctive finding: a persistent drain was traced to the dash control panel unit itself, not an electrical short — plus a confirmed 48V mild hybrid alternator issue with a 7-year US extended warranty that UK owners have struggled to get equivalent support for.
Illustration for editorial purposes
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OEM Part Number: 000915105CC
| Common fitment | Audi OEM: 000915105CC (also cross-referenced as 7L0915105, 7P0915105E) |
|---|---|
| Later/superseded reference | Audi OEM: 000915105DG |
| Case size | Typically H6 (Group 48) — check your specific trim, since some performance variants (S3) have used AGM from the factory while others used flooded lead-acid |
| Note | A battery swap on this generation typically needs registering to the car's Battery Management System so the charging strategy matches the newly fitted capacity and technology. |
Audi A3 Battery: The Part Everyone Blames First, Not Always Correctly
On the Audi A3, no single component gets blamed for a no-start more than the battery, and often that blame is justified, making it a sensible first check. But it isn't the whole story every time, so it's worth confirming before spending on a replacement that might not actually fix anything.
Audi A3 Battery: What It Does
Whenever the Audi A3's engine isn't turning, the 12V battery is what keeps electrical systems running and handles the next start. That workload is much higher on stop-start versions, given how often the engine switches off and restarts, which is exactly why they call for an AGM or EFB battery rather than a standard type.
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A Genuinely Distinctive, Real Finding Worth Knowing About Persistent Drains — Audi A3 Battery
If the battery keeps going flat within days despite everything appearing switched off, this is genuinely worth knowing: one documented case saw a persistent drain traced not to an electrical short or a failing alternator, but to the dash control panel unit itself, the one displaying average MPG, remaining fuel range, and similar trip information. Replacing this specific unit resolved the drain entirely, worth knowing this distinctive component can be the genuine cause even when more obvious suspects have been ruled out. It's also genuinely worth knowing a useful diagnostic reading: a healthy trickle charge to the alarm system typically measures around 0.03 amps at rest, so anything notably higher than this when tested with a multimeter across the battery terminals points toward a genuine parasitic drain worth investigating further, rather than normal background current draw.
It's also genuinely worth knowing a practical concern worth addressing before replacing the battery yourself: disconnecting the old battery can result in various computer settings and stored preferences being lost, worth using a proper memory-saving device connected to the car's diagnostic port during the swap if you want to avoid having to reconfigure these afterward.
Audi A3 Battery: 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.