Peugeot 508 Battery: Specs, Fitment & Common Faults

A genuine, real account: a 508 owner had a new £400 Battery Protection Module and a new battery fitted, and stop-start still barely worked — worth knowing before assuming a permanent fix exists.

Illustration for editorial purposes

OEM Part Numbers

Accuracy note: we weren't able to verify a confident Peugeot 508 battery part number at the time of writing. Please confirm the correct part via a Peugeot dealer or parts specialist using your VIN.

A Genuinely Important, Real Account: A £400 Repair That Didn't Fully Fix It

Worth knowing before assuming a fault, or paying for an expensive repair expecting it to be the final answer: one 508 owner had a new Battery Protection Module fitted by their dealer (costing around £400) along with a genuine replacement Bosch battery specifically rated for stop-start duty. Even after a long motorway run, stop-start still only activated infrequently, and a battery conditioner afterward showed just 12.1V — improving temporarily after charging, but only for a short time. This is worth knowing simply to set realistic expectations: an expensive module and battery replacement doesn't automatically guarantee stop-start will work reliably afterward.

Before assuming a fault at all: Peugeot's own manual lists specific conditions where stop-start deliberately won't activate, including being on a steep slope, the driver's door being open, the seatbelt unfastened, not yet having reached 6mph since the last start, the electric parking brake being applied, or the system needing the engine running to maintain cabin temperature or demist the windscreen. It's worth ruling these out first, though as the case above shows, even doing so doesn't guarantee a subsequent repair will fully resolve genuine charge-sensitivity issues on these later systems.

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.

Fitment & Compatibility

Battery type and capacity differ between standard and stop-start equipped versions of the 508, and fitting a standard battery to a stop-start car can cause premature failure since it's not designed for the frequent cycling involved. Always confirm the exact battery type and capacity for your specific trim before ordering. Whether you're sourcing a replacement battery for your Peugeot 508 from a dealer, specialist, or online marketplace, always check compatibility against your registration or VIN before buying.

Common Faults

Symptoms of Failure

Slow or laboured engine cranking — often the earliest sign, especially noticeable in cold weather.
Dashboard warning light — a battery or charging system alert shouldn't be ignored, even if the car still starts normally.
Electrical accessories behaving oddly — flickering lights or a stuttering infotainment system can point to inconsistent voltage.
Stop-start system disabling itself — many cars automatically turn off stop-start when battery health drops, a useful early warning most drivers miss.

DIY Replacement Difficulty

This is generally an easy DIY job on most versions, though modern cars increasingly require a "battery registration" step using a diagnostic tool afterward so the car's charging system recognises the new battery correctly. Skipping this step on cars that need it can lead to reduced battery lifespan even with a brand new unit. Expect 15–30 minutes for the physical swap, plus registration if your specific car requires it.

OEM vs. Aftermarket

Reputable aftermarket batteries from established brands are widely regarded as a safe, reliable alternative to OEM parts, provided the type (standard, AGM, or EFB) and capacity match your car's requirements exactly. This is one part where matching the correct specification matters far more than the brand name on the case.

More Peugeot Battery Guides

The same part, covered across other Peugeot models.