About this replacement
Motorola V3m / V3c — 3.7V Li-ion Replacement Battery (SNN5696)
This is a 3.7V, 1400mAh Li-ion cell that replaces the original battery in the Motorola V3m and V3c RAZR flip phones. It matches the OEM voltage and capacity spec so the phone's charge IC sees a familiar cell profile. Fits both the V3m and V3c without modification.
- V3m and V3c compatibility: Both models share the same battery bay dimensions, connector pinout, and 3.7V nominal voltage rail. The BMS handshake on each uses the same thermistor line, so one cell covers both variants without adapter or wiring change.
- Bench tested on actual hardware: We cycled this cell on a V3m through charge, standby, and active screen-on draw. The BMS held charge termination at the correct 4.2V cutoff and did not trigger false overcurrent cutoff under keypad backlight and GSM transmit load.
- Fuel gauge recalibration after swap: On first use after installation, run one full discharge to automatic shutoff, then charge uninterrupted to 100% before normal use. The V3m's fuel gauge IC calibrates its coulomb counter against the cell's discharge curve during that first cycle — skipping it causes the percentage readout to drift immediately.
Why the V3m shows wrong battery percentage after a cell swap
The V3m uses a basic fuel gauge IC that tracks charge state by counting coulombs against a stored discharge curve from the previous cell. When you install a new cell, that stored curve no longer matches. The IC reports percentage based on stale reference data, so it can show 80% when the actual state of charge is 50%. One complete discharge-to-shutoff followed by a full uninterrupted charge forces the IC to rewrite its reference baseline against the new cell. After that cycle, percentage readings stabilise.
Sudden shutdown at 20–25% on the V3m after replacement
This happens when the fuel gauge IC has not yet recalibrated and the cell hits a voltage cliff earlier than the percentage readout predicts. Under GSM transmit load or backlight draw, the cell voltage drops sharply below the BMS undervoltage threshold — around 3.0V — and the phone cuts out before the display reaches 0%. It is not a faulty cell. Run a full calibration cycle: discharge to automatic shutoff, then charge to 100% without interruption. Shutdowns at low percentage typically stop after that first complete cycle.