Swissvoice MP50 Replacement Battery 3.7V 800mAh 061024

Swissvoice MP50 — 3.7V Li-ion Replacement Battery (061024)

This is a 3.7V, 800mAh Li-ion cell for the Swissvoice MP50 mobile phone. It replaces OEM part 061024 when the original cell no longer holds charge or fails to power the device. Capacity is 2.96Wh, matching the original specification.

• MP50 fit and connector: The MP50 uses a compact 48.04 × 41.60 × 4.70mm cell with a low-current BMS suited to its single-core modem and small display load. The connector and protection circuit match the OEM board layout — no modification needed.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the MP50 platform. The BMS accepted the charge IC handshake on the first cycle, and the protection circuit tripped correctly at low-voltage cutoff without locking the board.
• Fuel gauge recalibration on first use: After fitting this cell, disable fast charging and run one full discharge-to-charge cycle before normal use. This lets the fuel gauge IC map its coulomb counter against the new cell's discharge curve — skipping this step causes the percentage readout to drift or jump in the first week.

Sudden shutdown at 20–30% on the Swissvoice MP50

This happens when the fuel gauge IC is still calibrated to the old cell's discharge curve. The new cell hits a voltage cliff under screen or call load that the old curve did not predict. The phone reads 25% but the cell voltage has already dropped below the BMS cutoff threshold. One complete discharge cycle — run it down to auto-shutdown, then charge uninterrupted to 100% — resets the coulomb counter and eliminates the early cutoff.

MP50 not powering on after the replacement cell sat in storage

Li-ion cells self-discharge in storage. If this battery sat below 2.5V per cell, the BMS enters lockout to prevent damage and the phone will not respond to the power button. Connect the phone to a wall charger — not a PC USB port — and leave it for 20–30 minutes without pressing anything. The charge IC will trickle current into the cell until voltage clears the BMS re-initialisation threshold, typically around 2.9V, at which point normal charging resumes.