Marshall Major V Replacement Battery 3.8V 830mAh Li-Polymer

Marshall Major V — 3.8V Li-Polymer Replacement Battery (AHB632832)

This 3.8V, 830mAh Li-Polymer cell replaces the original AHB632832 battery inside the Marshall Major V wireless over-ear headphones. It restores Bluetooth audio playback when the factory cell has degraded and no longer holds adequate charge. Dimensions are 34.30 × 28.00 × 6.60mm — confirm these against your existing cell before fitting.

• Marshall Major V fit: The Major V runs a single Li-Polymer cell at 3.8V. The AHB632832 part number matches the original cell's footprint, connector, and BMS communication protocol — the headphone's charge controller will recognise it without reconfiguration.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Major V platform. The BMS accepted the new pack cleanly, hit full charge voltage without fault flags, and held stable output under sustained Bluetooth audio draw.
• First-charge protocol for the Major V: Charge the headphones to full via USB-C before the first listening session. The Major V's fuel-gauge IC calibrates its capacity estimate against a complete charge cycle — skip this and the battery indicator will read inaccurately from day one.

Why the Major V cuts out during playback on a new battery

A freshly installed Li-Polymer cell ships at storage voltage — typically 3.6–3.7V, not full charge. The Major V's BMS sets a low-voltage cutoff that can trip under the combined draw of the Bluetooth radio and audio amplifier before you expect it. This is not a faulty cell. One full charge cycle from storage voltage brings the cell to 4.2V and gives the BMS a proper baseline to work from.

Battery indicator stuck at full or dropping suddenly after replacement

The Major V uses a coulomb-counting fuel gauge that tracks charge state relative to a learned capacity profile. Swapping in a new cell resets that profile, so the indicator often reads incorrectly for the first few cycles. Run three complete charge-to-full, play-until-low cycles and the gauge recalibrates itself. After the third cycle the indicator should track normally across the full voltage range of 3.0V to 4.2V.