JNC SSF-M3 20GB Compatible Battery 3.7V 1100mAh Li-ion

JNC SSF-M3 20GB — 3.7V Li-ion Replacement Battery (PPCW0401 / PPCW0504)

This is a 3.7V, 1100mAh Li-ion replacement battery for the SanDisk Sansa Fuze M3 20GB portable media player. It fits the original battery slot and matches the OEM voltage and capacity spec. If your Fuze no longer holds a charge or drains faster than it used to, this is the direct swap.

• SSF-M3 20GB compatibility: The Sansa Fuze M3 20GB uses a single-cell Li-ion pack with a specific three-pin connector and a BMS that monitors cell voltage for audio amplifier regulation. This battery matches that connector pinout and voltage threshold so the player's charge indicator reads accurately from the first cycle.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the Fuze platform. The BMS handshake completed without fault codes, and the protection circuit tripped correctly at low-voltage cutoff — no runaway draw during playback testing.
• First-charge protocol for the Fuze M3: Charge fully before first use — media players often enter a deep discharge protection state after extended storage. The Fuze may show no charge activity for the first 20–30 minutes; this is the trickle phase before normal charge current kicks in. Do not interrupt it.

Battery percentage jumping after a cell swap on the Sansa Fuze

The Fuze's fuel gauge uses a voltage-threshold model to estimate charge level. After a new cell goes in, the firmware's stored voltage curve no longer matches the new cell's actual discharge profile. This causes the percentage display to jump — often reading 100%, then dropping sharply mid-session. Run two full charge-to-discharge cycles and the gauge recalibrates to the new cell's behaviour.

Playback cutting out before the battery indicator shows empty

At the tail end of a discharge curve, cell voltage sags under the load of the audio amplifier. The Fuze's amplifier circuit needs a minimum rail voltage to sustain output — when an aged or degraded cell can no longer hold that rail, the player cuts audio or shuts off even though the gauge still shows remaining charge. A new cell with a flatter discharge curve holds the rail longer. If cutouts persist after the swap, check that the battery connector is fully seated — a loose pin creates resistance that mimics voltage sag.