Harman/Kardon Onyx Studio Compatible Battery LI11B001F 3.7V

Harman/Kardon Onyx Studio 1 & 2 — 3.7V Li-ion Replacement Battery (LI11B001F)

This is a 3.7V 3400mAh Li-ion cell that replaces part LI11B001F in the Harman/Kardon Onyx Studio 1 and Onyx Studio 2 portable Bluetooth speakers. Both models share the same battery bay geometry and BMS handshake, so one cell covers both. Capacity is 3400mAh (12.58Wh), matching the original specification.

• Onyx Studio 1 and 2 shared platform: Harman/Kardon used the same internal battery tray, connector pinout, and BMS communication protocol across both Studio generations. The cell voltage rail feeds both the amplifier board and the Bluetooth radio from a single pack — swapping in this cell restores both functions without any firmware conflict.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the Studio platform. The BMS accepted the pack without error flags, voltage stabilised at 4.18V at top-of-charge, and the protection circuit triggered correctly at low-cell cutoff before audio distortion set in.
• Onyx Studio charge cycling tip: These speakers often sit plugged in on a desk between uses. Let the pack discharge below 20% at least once a month before recharging — constant top-off charging without a full discharge causes fuel gauge drift and accelerates capacity fade on the Li-ion cell.

Audio distorting before the battery indicator reaches empty

As a Li-ion cell ages, its internal resistance rises. At high volume, the amplifier draws a sharp current spike that causes the cell voltage to sag below what the amp board needs — even though the fuel gauge still reads 20–30% remaining. The audio circuit clips before the battery protection trips, so you hear distortion long before a low-battery warning. A fresh cell at 3400mAh restores the voltage headroom the amplifier needs at peak draw. If distortion still appears on a new cell, confirm charge voltage reaches 4.18–4.20V at full charge before use.

Bluetooth dropping out at high volume on a replacement cell

The Bluetooth radio and the amplifier both draw from the same 3.7V cell. At loud listening levels, the amplifier's instantaneous current demand spikes hard enough to pull cell voltage down momentarily. This voltage sag starves the radio, causing the Bluetooth stack to drop the connection. The fix is to check that the replacement cell is fully charged to 4.18–4.20V before the first session — a partially charged cell has higher internal resistance and sags more under combined amp-plus-radio load. If drop-outs persist at full charge, reduce volume by 10–15% to bring current draw below the sag threshold.