Thomson X-2400 Replacement Battery 3.7V 1800mAh 28B7001

Thomson X-2400 — 3.7V Li-ion Replacement Battery (28B7001)

This is a 3.7V, 1800mAh Li-ion battery for the Thomson X-2400 portable media player. It replaces OEM part number 28B7001 and fits directly into the X-2400 housing. Use it when your original cell no longer holds a charge or the player fails to power on.

• X-2400 platform fit: The X-2400 runs a single-cell 3.7V Li-ion architecture with a BMS that monitors cell voltage before allowing the player to boot. This battery matches that voltage rail and connector, so the BMS handshake completes without triggering a false low-battery lockout.
• Bench tested on actual hardware: We cycled this battery through a full charge and discharge on an X-2400 unit. The BMS accepted charge current normally, stepped down to trickle at 4.2V, and the player booted cleanly without entering protection mode.
• First-charge protocol for this player: If the X-2400 was stored for several months before swapping this battery in, connect it to the charger and leave it for at least 30 minutes before attempting to power on. Extended storage can push the cell into deep-discharge protection, and the player will not respond to the power button until a slow trickle charge brings the cell voltage above the BMS threshold.

Battery percentage jumping after cell swap on the X-2400

After fitting a new cell, the X-2400's voltage-threshold indicator needs a full charge-discharge cycle to recalibrate. The player reads state-of-charge by sampling cell voltage at fixed thresholds, not by a fuel gauge IC. A new cell with a different discharge curve can cause the percentage to jump from 80% to 20% mid-session until the firmware re-maps the thresholds. Run one complete charge to 4.2V and a full discharge before trusting the indicator.

Playback cutting out before the battery indicator shows empty

The X-2400's audio amplifier draws a short current spike every time it drives the output stage, and an aged or partially discharged cell can sag below the minimum operating voltage during that spike. The player interprets this as a critical low-voltage event and cuts the audio or shuts down, even when the indicator still shows charge remaining. This is a voltage-sag issue, not a capacity issue — the cell cannot sustain the instantaneous current demand. Fitting a new cell at full charge resolves the sag; if it persists, check that the battery connector is fully seated and making clean contact.