Marshall Stockwell 11.1V Replacement Battery 3400mAh Li-ion

Marshall Stockwell — 11.1V Li-ion Replacement Battery (TF18650-2200-1S3PA)

This 11.1V 3400mAh Li-ion battery is a direct replacement for the Marshall Stockwell portable Bluetooth speaker. It slots into the same battery bay as the original TF18650-2200-1S3PA pack. Voltage, capacity, and connector match the Stockwell's onboard power management circuit.

• Stockwell platform fit: The Stockwell runs an 11.1V three-cell Li-ion configuration. This pack matches that rail exactly, so the fuel gauge IC reads cell voltage correctly and the BMS handshake completes without a fault condition.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on a Stockwell unit. The BMS accepted the cells without triggering overcurrent or undervoltage cutoff, and the speaker reached full output level without voltage sag causing amplifier shutdown.
• Monthly discharge cycle for the Stockwell: Let the speaker run down below 20% at least once a month before plugging in. The Stockwell is often left on a desk charging continuously — that constant top-off without a full discharge causes fuel gauge drift and accelerates capacity fade on the Li-ion cells.

Audio distorting before the battery indicator reaches empty

As Li-ion cells age, internal resistance rises. Under the amplifier's current draw, cell voltage sags faster than the fuel gauge tracks. The Stockwell's amplifier hits its minimum supply voltage and clips the audio signal before the battery LED shows low. With a fresh pack at full 11.1V nominal, that voltage margin returns and clipping stops at normal listening levels. If distortion still appears on a new battery, check the charging cable — a resistive micro-USB cable causes incomplete charges that start every session already voltage-reduced.

Stockwell showing full bars but audio drops after an hour of play

Shallow cycling — always topping off before the pack drops below 50% — causes the fuel gauge IC to lose calibration against the actual cell capacity. The indicator reads full, but the usable charge window has drifted. Run the Stockwell down to below 20% until the low-battery LED activates, then charge uninterrupted to 100%. One full cycle like this resets the fuel gauge reference point and restores accurate charge reporting.