Infinity One Premium Replacement Battery 7.4V 5000mAh

Infinity One Premium — 7.4V Li-Polymer Replacement Battery (MLP5457115-2S)

This 7.4V, 5000mAh (37Wh) Li-Polymer pack replaces the OEM battery in the Infinity One Premium portable Bluetooth speaker. It slots into the same cell bay and reconnects to the same BMS handshake points as the original. Use this when the existing pack no longer holds a charge or swells inside the housing.

• Infinity One Premium compatibility: The One Premium uses a 7.4V two-cell Li-Polymer configuration with a fixed connector and BMS communication line. This replacement matches that cell topology, connector pinout, and cell dimensions (117.00 × 57.30 × 12.13mm) so the speaker's protection circuit reads the pack correctly.
• Bench tested on actual hardware: We cycled this pack through full charge and load discharge passes. The BMS held cell balance across both cells without triggering overcurrent cutoff, and the speaker's charge indicator tracked state-of-charge accurately through the full swing.
• Monthly discharge cycle for the One Premium: Let the speaker play down below 20% at least once a month before recharging. The One Premium is typically left on a desk and topped off constantly — that shallow-cycle habit drifts the fuel gauge and shrinks usable capacity faster than normal discharge does.

Audio distorting before the battery indicator reaches empty on the One Premium

At high playback volume, the amplifier and Bluetooth radio draw together can pull the pack voltage below the amplifier's clean operating threshold before the fuel gauge registers low. When cell voltage sags under that combined load, the amp clips the signal instead of cutting out cleanly. The distortion sounds like crackling or thinning bass at full volume, but the LED still shows two or three bars. Dropping volume one or two steps reduces instantaneous current draw and typically clears the distortion immediately.

One Premium won't wake up from USB-C after sitting discharged for several weeks

Li-Polymer cells that self-discharge below roughly 2.5V per cell (5.0V pack total) drop under the minimum acceptance voltage for USB-C Power Delivery negotiation. The charger cannot initiate a session because the pack won't respond to the PD handshake. Use a charger with a trickle or pre-charge mode — or hold the power button for 10 seconds while the cable is connected — to push a small recovery current into the cells before normal charging resumes. Once the pack climbs above 6.0V, standard USB-C charging takes over automatically.