Toshiba Gigabeat MEGF10 Replacement Battery 3.7V 1000mAh

Toshiba Gigabeat MEGF Series — 3.7V Li-ion Replacement Battery (MK11-2740)

This is a 3.7V, 1000mAh Li-ion battery for the Toshiba Gigabeat MEGF10, MEGF20, MEGF40, and MEGF60 portable media players. It replaces OEM part number MK11-2740. These mid-2000s players share the same battery bay, connector, and BMS handshake across the MEGF line.

• MEGF10 / MEGF20 / MEGF40 / MEGF60 compatibility: All four models use the same 3.7V single-cell configuration with an identical connector pinout and BMS communication protocol. Swapping the same cell across the MEGF lineup was a deliberate Toshiba platform decision — the battery registers identically on each unit.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the MEGF platform. The BMS accepted the cell without error flags, charge current ramped normally from trickle to CC/CV, and termination cut off at the correct voltage ceiling.
• First charge after a long storage gap: If the device has sat unused for months, connect the charger and leave it for at least 30 minutes before attempting to power on. Deeply discharged Li-ion cells in MEGF players trip a protection state that blocks normal charge current until the cell voltage climbs above the BMS wake threshold.

Battery percentage jumping after a cell swap on the MEGF series

The Gigabeat MEGF uses a voltage-threshold gauge — it estimates charge level by reading cell voltage, not a fuel-gauge IC. After a cell swap, the firmware hasn't mapped the new cell's discharge curve yet. Expect the indicator to read inaccurately for the first two or three full charge-discharge cycles. Run the battery down until the player shuts off, then charge fully to 4.2V. The reading stabilises once the firmware has sampled the new cell's voltage at both ends of its range.

Playback cutting out before the battery indicator shows empty

As the cell discharges toward its lower voltage floor, the audio amplifier in the MEGF draws a brief surge of current during playback. If cell voltage is already low, that surge drags voltage below the BMS cutoff threshold and the player shuts down — even though the on-screen indicator still shows charge remaining. This is a voltage-sag problem, not a capacity problem. It becomes more pronounced with aged cells whose internal resistance has climbed. A fresh cell at 1000mAh will sustain the voltage rail under that load down to the true cutoff at approximately 3.0V.