Mercedes-Benz CLA Battery: Specs, Fitment & Common Faults

A genuinely useful finding: the one-touch window and sunroof function typically needs to be re-synced after a battery change, with the procedure detailed in the owner's handbook — plus an honest finding that most Mercedes models genuinely don't need coding for a like-for-like swap.

Illustration for editorial purposes

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OEM Part Number: A0019828208

Genuinely important to know: 2014-2019 CLA-Class models have two separate 12V batteries — a main AGM battery for starting, and a smaller auxiliary battery dedicated to the ECO start/stop system. If the auxiliary fails, the car remains drivable but start/stop disables; if the main battery fails, the car may not start at all. Any main battery replacement must be registered with the vehicle's computer via a diagnostic tool, or the new battery can fail prematurely.

Main battery, genuine reference (shared with A/B/GLA-Class)	Mercedes-Benz OEM: A0019828208 (also referenced as A0019828026) — AGM, Group H6/H8, 70-80Ah, 750-800 CCA
Auxiliary battery, genuine reference	Mercedes-Benz OEM: A2115410001 (also referenced as N000000004039) — small AGM, 12-14Ah
Battery cable/wiring harness, genuine reference	Mercedes-Benz OEM: A2465405933

Mercedes-Benz CLA Battery: The Part Everyone Blames First, Not Always Correctly

Ask anyone why their Mercedes-Benz CLA won't start and "the battery" is usually the first guess, and it's frequently correct, which makes it a reasonable starting point. It's not always right, though, so it's worth ruling out other causes before spending on a replacement that changes nothing.

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.

Mercedes-Benz CLA Battery: What It Does

On the Mercedes-Benz CLA, powering the engine start and running electrics while the engine's stopped both fall to the 12V battery. Stop-start technology puts significantly more strain on it than older designs, thanks to how frequently the engine cycles — explaining why a specific AGM or EFB battery is needed rather than a standard unit.

Mercedes-Benz CLA Battery reference plate

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A Genuinely Useful Finding Worth Knowing About What Needs Resetting — Mercedes-Benz CLA Battery

After a battery change, this is genuinely worth knowing: the one-touch function for the electric windows, and the sunroof if fitted, typically needs to be re-synced afterward, with the specific procedure detailed in the owner's handbook. Worth checking this rather than assuming a fault if these features stop responding correctly to a single tap post-replacement.

A genuinely honest, real finding worth knowing: unlike some other German manufacturers, most Mercedes models genuinely don't require any coding or registration for a simple, like-for-like battery replacement. The only genuine coding requirement is if you're switching battery types entirely, such as fitting an AGM battery in place of a standard flooded unit.

It's also genuinely worth knowing that intermittent electrical glitches, such as random warning chimes or unexpected wiper activation, can be a sign of an ageing battery on a car of a certain age, worth having it properly load-tested before assuming a more complex fault.

Mercedes-Benz CLA 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 Mercedes-Benz Battery

The same part, covered across other Mercedes-Benz models.