Sony SRS-X1 Replacement Battery 3.7V 1000mAh LIS1553(SY6)

Sony SRS-X1 — 3.7V Li-Polymer Replacement Battery (LIS1553(SY6))

This is a 3.7V, 1000mAh Li-Polymer battery for the Sony SRS-X1 compact Bluetooth speaker. It replaces part number LIS1553(SY6) and fits directly into the SRS-X1 housing. Use it when the original cell no longer holds enough charge for normal playback sessions.

• SRS-X1 fit and connector match: The SRS-X1 runs a single-cell Li-Polymer pack at 3.7V nominal. This replacement matches the OEM footprint at 47.56 × 32.20 × 6.40mm and uses the same connector orientation, so the BMS handshake with the speaker's charge circuit initialises correctly on first connection.
• Bench tested on actual hardware: We cycled this cell through the SRS-X1 charge circuit and confirmed the BMS accepted charge without fault flags. Voltage held stable across the amplifier's combined Bluetooth radio and audio draw, with no mid-session cutoff under sustained output.
• Discharge cycle for SRS-X1 daily users: If the speaker sits on a desk and gets topped off before dropping below 50%, the fuel gauge drifts over weeks. Let the cell discharge below 20% at least once a month before recharging to keep capacity reporting accurate.

Why the SRS-X1 cuts audio at high volume before the battery indicator reaches empty

At maximum volume, the SRS-X1 amplifier and Bluetooth radio draw current simultaneously. On a worn cell, this combined spike pulls terminal voltage below the amplifier's operating threshold faster than the fuel gauge can update. The speaker clips or mutes while the indicator still shows remaining charge. A fresh cell with low internal resistance sustains voltage under that peak draw and eliminates the premature dropout.

SRS-X1 not responding to USB charge after sitting unused for months

Li-Polymer cells that self-discharge below roughly 2.5V enter a deep-discharge state where the protection circuit blocks incoming charge. The speaker shows no charge indicator and appears dead. Some chargers reject the pack entirely at this voltage. Use a charger that supports a trickle or recovery mode — apply a low-current charge (around 50–100mA) until cell voltage climbs above 3.0V, at which point the protection circuit releases and normal charging resumes.