Sony NWZ-S600 Replacement Battery 3.7V 750mAh Li-Polymer

Sony NWZ-S600 / NWZ-S610 / NWZ-S615 Series — 3.7V Li-Polymer Replacement Battery (1-756-763-11)

This is a 3.7V, 750mAh Li-Polymer replacement battery for the Sony NWZ-S600 series of portable digital audio players. It fits the NWZ-S600, NWZ-S600F, NWZ-S610, NWZ-S615, and nine additional variants sharing the same internal battery bay. OEM cross-references include 1-756-763-11, LIS1401, and 7Y19A60823.

• NWZ-S600 series compatibility: These models share a common 3.7V Li-Polymer cell format, connector pinout, and BMS handshake protocol across the entire sub-series. A single replacement cell fits all listed variants without modification.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the NWZ-S610. The BMS accepted the cell without error flags, charge termination triggered correctly at 4.2V, and low-battery cutoff activated at the expected threshold without premature shutdown.
• Post-swap charge protocol for NWZ-S600 players: After fitting this cell, connect the player to its charger before attempting to power it on. If the device has been in storage, the cell voltage may have dropped low enough to trigger deep-discharge protection — the player will not respond to the power button until the charger has pushed enough current to exit that state.

Battery percentage jumping after cell swap in the NWZ-S600

Sony's NWZ-S600 firmware tracks battery state using stored voltage-threshold calibration data from the previous cell. When a new cell goes in, that stored data no longer matches the actual discharge curve of the replacement. The indicator can jump from 80% to 20% or read full while the device is still on its first charge. Run two or three complete charge-to-cutoff cycles and the firmware recalibrates its thresholds to the new cell's characteristics.

Playback cutting out before the battery indicator shows empty

The NWZ-S600's audio amplifier draws a brief current spike during playback — particularly at higher volume levels — that can exceed what a heavily degraded original cell can sustain. This causes the cell voltage to sag below the BMS cutoff point momentarily, triggering shutdown even though the indicator hasn't reached zero. A fresh 750mAh cell at full charge holds its voltage rail stable under that amplifier load. If playback still cuts out after fitting this replacement, check that the cell is reading above 3.9V at rest before starting playback.