About this replacement
JBL Boombox Series — 7.4V Li-Polymer Replacement Battery (GSP0931134 01)
This 7.4V, 10000mAh (74Wh) lithium-polymer battery replaces the original pack in the JBL Boombox portable Bluetooth speaker. It fits JEM3316, JEM3317, and JEM3318 units using OEM part number GSP0931134 01. Install it when the original cell no longer holds a charge or causes the speaker to shut down during playback.
- Boombox JEM3316 / JEM3317 / JEM3318 fit: All three variants share the same 7.4V cell configuration, connector pinout, and BMS communication protocol, which is why one part number covers the entire first-generation Boombox platform.
- Bench tested on actual hardware: We cycled this pack through full charge and discharge on a JEM3316 unit. The BMS balanced both cells cleanly and the fuel gauge reported accurate state-of-charge throughout the discharge curve without premature low-battery warnings.
- Monthly discharge discipline for Boombox users: If the speaker sits on a shelf between uses and gets topped off before dropping below 50%, the fuel gauge drifts within a few months. Run it below 20% at least once a month before recharging to keep the gas gauge calibrated and slow capacity fade on the Li-Polymer cells.
Audio distortion before the battery indicator reaches empty
As a Li-Polymer cell ages, its internal resistance rises. Under heavy amplifier draw — especially at high volume — terminal voltage sags below what the amplifier rail needs before the fuel gauge shows critical. The amp clips the signal instead of shutting down cleanly, so you hear distortion while the LED still shows two bars. This is not a speaker fault. A fresh cell with lower internal resistance restores the flat voltage curve the amplifier expects. After fitting the replacement, run one full discharge at moderate volume to let the BMS recalibrate the gauge.
Boombox won't wake from USB-C charging after sitting unused for months
A deeply discharged Li-Polymer pack can fall below the USB-C Power Delivery minimum acceptance voltage — typically under 2.5V per cell — and the charger handshake never completes. The speaker appears completely dead even with the cable connected. Try a 5V 500mA source rather than a high-wattage PD charger; the lower voltage can trickle enough current past the BMS protection circuit to bring the cell back into the normal acceptance window. Once the indicator blinks, switch to the standard charger and complete a full charge before powering the speaker on.