Subaru Forester Battery: Specs, Fitment & Common Faults
A genuinely honest, frustrating real account: a battery replaced twice under warranty with a four-day drain test finding nothing, dismissed by the dealer as simply "not driving the car enough" — plus a distinctive symptom pointing to a possible intermittent electronic fault instead.
Illustration for editorial purposes
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OEM Part Number: 82110AA012
| Genuine fitment (2012-2018, shared with BRZ, Crosstrek, Impreza, STI, WRX) | Subaru OEM: 82110AA012 (also referenced as 82110AA010, 82110AA011) — 55D23L, 48Ah, 390 CCA |
|---|---|
| Genuinely worth knowing | UK owners have reported the standard 390 CCA rating feels weak in practice, particularly in cold weather, with a higher-CCA replacement (60Ah or more, matching or exceeding the original 55D23L dimensions) often recommended as a genuine improvement. |
| Important, Start/Stop equipped models | Match the original battery's design type (EFB vs AGM) rather than assuming AGM is automatically better — the charging software is calibrated for a specific type, and mismatching it can reduce battery life. |
Subaru Forester Battery: The Part Everyone Blames First, Not Always Correctly
On the Subaru Forester, more non-starts get pinned on the battery than on any other single component, and that assumption is correct often enough to justify checking it first. It's not always the real cause, though, so it's worth confirming before spending money on a replacement that doesn't fix the problem.
Subaru Forester Battery: What It Does
On the Subaru Forester, every engine start and every moment the electrical systems run without the engine turning draws on the 12V battery. Stop-start puts far more demand on that battery than older designs, given how often the engine cycles off and on — hence the need for an AGM or EFB battery instead of a standard type.
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A Genuinely Honest, Frustrating Real Account Worth Knowing — Subaru Forester Battery
If you're facing a recurring flat battery despite the battery itself testing fine and even being replaced, this is genuinely worth knowing: one documented case saw the battery replaced under warranty twice, with a four-day parasitic drain test at the dealer finding absolutely nothing wrong, before the dealer's explanation simply became that the owner "doesn't drive the car enough." The owner had previously driven an earlier Forester in exactly the same pattern for years with no issues at all — worth knowing this kind of dismissive explanation doesn't necessarily mean there's genuinely nothing wrong, particularly if your usage pattern hasn't meaningfully changed from a previous car that never had this problem.
It's also genuinely worth knowing that the Data Communication Module, responsible for connected services, has been documented as a confirmed cause of flat batteries on related Subaru models after standing for extended periods — worth asking a dealer directly about this specific component if you're facing a similar pattern.
Subaru Forester 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 Subaru Battery
The same part, covered across other Subaru models.