Vodafone 351 Li3708T42P3h553447 Replacement Battery 3.7V 800mAh

Vodafone 351 / VF351 / 353 — 3.7V Li-ion Replacement Battery (Li3708T42P3h553447)

This is a 3.7V, 800mAh Li-ion replacement battery for the Vodafone 351, VF351, and 353 smartphones. It matches OEM part numbers Li3708T42P3h553447 and Li3707T42P3h553447. The cell sits at 54.29 x 33.71 x 4.43mm and slots directly into the original battery bay.

• 351, VF351, and 353 compatibility: These three models share the same battery bay dimensions, connector pinout, and 3.7V power rail. The BMS handshake protocol is identical across the range, so one cell covers all three without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the 351 platform. The BMS accepted the cell cleanly, charge termination triggered at the correct voltage, and protection circuits tripped as expected under overcurrent load.
• First-cycle fuel gauge recalibration: After fitting this cell, disable fast charging and run one full discharge-to-charge cycle before resuming normal use. This lets the fuel gauge IC map the new cell's discharge curve before any high-current charging pushes into an uncalibrated state.

Sudden shutdown at 20–30% on the replacement cell

The Vodafone 351 modem and display draw a combined spike load that the cell must sustain at lower state-of-charge. If the fuel gauge IC is still calibrated to the old, degraded cell curve, it reports a higher percentage than the actual cell voltage. When the new cell hits the real voltage floor under that load spike, the BMS cuts power instantly — the phone reads 25% and shuts off. Run one full discharge cycle from 100% to automatic cutoff, then charge uninterrupted to 100%. After that cycle, the coulomb counter resets to the new cell's curve and percentage readings stabilise.

Phone won't power on after the battery sat in storage

Li-ion cells stored below roughly 2.5V per cell trigger a BMS lockout — the protection circuit opens and the phone cannot draw enough current to boot. Plug the phone into a wall charger, not a PC USB port, and leave it connected for 20–30 minutes before pressing the power button. The charge IC on the 351 includes a trickle pre-charge mode that slowly recovers a deeply discharged cell back above the BMS re-enable threshold. If the screen shows nothing after 30 minutes on the wall charger, check that the charger output is at least 5V 1A.