JBL TAS8528P Replacement Battery 3.7V 3350mAh Li-ion ICA039NA

JBL TAS8528P / BAR 800 Series — 3.7V Li-ion Replacement Battery (ICA039NA)

This is a 3.7V Li-ion cell rated at 3350mAh (12.4Wh), built to fit the JBL TAS8528P and TAS8528M portable speakers as well as the BAR 800 and BAR 800 5.1.2-channel soundbar. It replaces OEM part numbers ICA039NA and DH036032CHM. Swap it in when the original cell no longer holds charge or the speaker refuses to power on from a full charge cycle.

• TAS8528 and BAR 800 platform fit: These models share the same battery bay dimensions (71 × 20 × 20mm), connector pinout, and BMS handshake protocol — the cell communicates state-of-charge data back to the speaker's onboard fuel gauge over the same two-wire interface used across this JBL generation.
• Bench tested on actual hardware: We cycled this cell through charge and load sequences on a TAS8528P unit. The BMS accepted charge without fault flags, voltage held stable under combined amplifier and Bluetooth radio draw, and the fuel gauge tracked accurately through the discharge curve.
• Monthly discharge cycle for TAS8528 users: If you keep this speaker plugged in or topped off constantly, run it down below 20% at least once a month before recharging. Constant shallow cycling without a full discharge causes the onboard fuel gauge to drift, so the speaker reports more charge than the cell actually holds.

Audio distorting before the battery indicator reaches empty on the TAS8528P

The TAS8528P amplifier stage needs a stable voltage rail to drive its output cleanly. As the Li-ion cell discharges toward the lower end of its curve — typically below 3.5V under load — the amplifier clips before the battery indicator registers empty. The indicator reads off an averaged fuel gauge sample, not the instantaneous cell voltage under peak draw. If you hear distortion while the indicator still shows one or two bars, check terminal voltage under load with a multimeter; a reading below 3.5V means the cell is closer to cutoff than the display suggests.

Bluetooth dropping at high volume on a freshly charged battery

At maximum volume, the amplifier and Bluetooth radio pull current simultaneously, spiking total draw well above what either subsystem requires alone. If the cell's internal resistance has risen — either from age on the original battery or a brief storage period on a new one — voltage sags enough during that combined spike to trigger the BMS protection circuit. The radio module drops first because the amplifier gets priority on the voltage rail. Run two or three full charge-discharge cycles to condition the cell, and confirm resting voltage sits at 4.1–4.2V before testing at high volume again.