About this replacement
Toshiba MK 11 — 3.7V Li-ion Replacement Battery
This is a 3.7V lithium-ion replacement battery rated at 850mAh (3.15Wh) for the Toshiba MK 11 PDA. It fits the MK 11 handheld directly and restores power to the device when the original cell no longer holds a usable charge. No OEM part number is published for this battery — fitment is confirmed by device model.
- MK 11 platform fit: The MK 11 series runs a single 3.7V cell architecture with a direct pin connector. Voltage and physical form factor must match exactly — this cell meets both requirements for the MK 11 without modification.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench and confirmed the BMS trips correctly at low-voltage cutoff. Charge acceptance from depleted state was normal, with no false-full readings at the first cycle.
- Sync before you swap: The MK 11 stores open application state and unsaved data in RAM powered directly by the main battery. Removing the battery without first syncing to a host computer will erase anything not written to flash. Complete a full data sync before pulling the old cell.
Why the MK 11 fails to boot after a new battery is installed
The MK 11 boot sequence checks for a minimum voltage threshold before initialising the operating system. A new cell shipped in a partially discharged state can fall below that threshold, causing the device to appear dead or stuck on a blank screen. This is not a fault with the battery or the unit. Place the device on charge for at least 30 minutes before attempting the first boot — this brings the cell above the minimum required for a clean startup.
Wireless sync dropping or slowing after a battery swap
The MK 11's wireless radio draws significantly more current than the device does at standby. If the replacement battery is not fully charged, voltage sag under radio load can cause the connection to drop mid-sync or reduce throughput. A partial charge that appears adequate for basic screen operation may still be insufficient to sustain the radio. Charge the battery to full — confirmed by the device's charge indicator clearing — before running a wireless sync session.