Jabra HFS100 Replacement Battery 3.7V 1400mAh AHB903740

Jabra HFS100 / Freeway — 3.7V Li-Polymer Replacement Battery (AHB903740)

This 3.7V, 1400mAh Li-Polymer battery replaces the original AHB903740 cell in the Jabra HFS100 and Freeway portable Bluetooth speakers. It restores wireless playback when the factory cell has degraded or failed to hold charge. Capacity listed is 1400mAh (5.18Wh) — taken directly from the product specification, not estimated.

• HFS100 and Freeway compatibility: Both the HFS100 and Freeway share the same battery bay dimensions and AHB903740 part number. The connector pinout and BMS handshake are identical across both models — no adapter or rewiring needed.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the HFS100 platform. The onboard BMS accepted the new pack without fault codes, and the fuel gauge tracked correctly from 0% to 100% across multiple cycles.
• Monthly discharge cycle for these speakers: Jabra HFS100 and Freeway units kept at a desk often get topped off before dropping below 50%. Do this once a month instead: let the speaker run down below 20% before recharging. Constant shallow cycling causes fuel gauge drift on the Li-Polymer cell and accelerates measurable capacity loss.

Bluetooth dropping at high volume on the HFS100

At maximum volume, the HFS100 amplifier draws a short current spike that hits the battery and the Bluetooth radio simultaneously. If the cell has any internal resistance — either from age or a degraded replacement — voltage sags under that combined load. The BMS reads the sag as a low-cell event and throttles output, which the radio interprets as a drop-out. A fresh cell with low internal resistance keeps voltage stable across both the amp and the radio under that combined draw.

Audio distorting before the battery indicator reaches empty

This happens when the amplifier is clipping under voltage sag, not when the battery is actually empty. As the cell discharges into its lower voltage curve, the amplifier no longer has enough headroom to reproduce peaks cleanly. The speaker's fuel gauge still shows one or two bars, but actual cell voltage has dropped enough to distort the audio signal. If you see this on a new cell, check that the cell voltage under load is staying above 3.4V — below that threshold the amp starts clipping before the BMS triggers shutdown.