JBL Wind 2 Replacement Battery GSP383555 3.7V 730mAh Li-Polymer

JBL Wind 2 — 3.7V Li-Polymer Replacement Battery (GSP383555 01)

This is a 3.7V, 730mAh Li-Polymer battery for the JBL Wind 2 portable Bluetooth speaker. It replaces OEM part GSP383555 01 and fits the Wind 2's internal battery bay at 56.80 × 40.00 × 3.00mm. Fit this when the original cell no longer holds a charge or the speaker shuts off during playback.

• Wind 2 form factor match: The Wind 2 uses a slim pouch-format Li-Polymer cell to fit its handlebar-mount housing. This replacement matches the OEM footprint exactly, so the connector seats without forcing and the cell lays flat without bowing the rear cover.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a Wind 2 unit. The onboard BMS accepted the cell without fault codes, balanced charging held at 4.2V, and the low-voltage cutoff triggered cleanly before the cell reached damaging depth.
• Fuel gauge recalibration after fitting: After installing a new cell, run the speaker down until it powers off on its own, then charge it fully in one uninterrupted session. The Wind 2's fuel gauge recalibrates on this first full cycle — skip it and the indicator will read inaccurately from day one.

Capacity fade on a speaker that never fully discharges

The Wind 2 is often charged at a desk or in a bag after short sessions — rarely below 50%. Shallow cycling like this causes Li-Polymer cells to lose calibration and accelerates capacity fade because the BMS never completes a full charge-discharge reference cycle. Over months, the speaker reports a full charge but actual usable capacity drops. Discharge the pack below 20% at least once a month to keep the fuel gauge anchored and slow cell degradation.

Audio distorting before the battery indicator reaches empty

At high volume the Wind 2's amplifier pulls current spikes that a partially degraded cell can't sustain cleanly. Voltage sags under the combined amplifier and Bluetooth radio draw, and the amp clips before the indicator shows low battery. The speaker sounds distorted but the gauge still shows one or two bars. This is a cell impedance issue, not a speaker fault — a fresh cell holds voltage above the amp's minimum rail, typically around 3.5V under load, and the distortion stops.