About this replacement
Harman/Kardon Onyx Studio 8 — 3.7V Li-ion Replacement Battery (ICA077NA)
This is a 3.7V 2600mAh Li-ion replacement cell for the Harman/Kardon Onyx Studio 8 portable Bluetooth speaker. It replaces the internal rechargeable pack when the original no longer holds charge. OEM part number ICA077NA.
- Onyx Studio 8 fitment: The Studio 8 runs a single-cell 3.7V Li-ion pack on a dedicated BMS that manages both the amplifier rail and the Bluetooth radio. This replacement matches the cell voltage, connector pinout, and BMS handshake required by the Studio 8 mainboard.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the Studio 8 platform. The onboard BMS accepted the cell without fault codes, balanced charge termination fired correctly at 4.2V, and the protection circuit tripped at the expected undervoltage threshold.
- Monthly discharge cycle for the Onyx Studio 8: The Studio 8 spends most of its life sitting on a desk at full charge between uses. Let the battery drop below 20% at least once a month before plugging in — constant top-off charging without a full discharge causes fuel gauge drift and accelerates capacity fade on the Li-ion cell.
Capacity fade from shallow cycling on the Onyx Studio 8
Li-ion cells in portable speakers degrade faster when they are constantly recharged from 70–80% without ever running low. The Studio 8 has no active cell-balancing circuit to compensate for fuel gauge drift caused by this pattern. Over time, the reported charge level decouples from actual cell capacity, so the speaker shuts off while the indicator still shows bars remaining. Replacing the cell resets this, but the same pattern will repeat if charging habits do not change.
Audio distorting before the battery indicator reaches empty
At high volume, the amplifier in the Studio 8 draws current in peaks that the aging cell cannot supply without voltage sag. The output stage clips under that sag before the battery indicator triggers low-battery cutoff. This is a cell internal-resistance problem, not an amplifier fault. A fresh cell with lower internal resistance handles the peak draw without the voltage drop that causes clipping.