Vodafone 354 Compatible Battery 3.7V 800mAh CAB3120000C1

Vodafone 354 — 3.7V Li-ion Replacement Battery (CAB3120000C1)

This 3.7V, 800mAh Li-ion cell replaces the original CAB3120000C1 battery in the Vodafone 354 and VF354 smartphones. It fits the same footprint at 49.34 × 40.00 × 4.45mm and drops into the battery bay without modification. Capacity figures come from product data — 800mAh, 2.96Wh.

• 354 and VF354 compatibility: Both model designations share the same battery bay dimensions, connector pinout, and BMS handshake protocol — one cell covers both variants without any adapter or wiring change.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the 354 platform. The BMS accepted the cell without rejection flags, and charge current stepped down correctly at the top-of-charge threshold.
• Fuel gauge recalibration on first use: After fitting this replacement, disable any fast-charge mode and run one complete discharge-to-charge cycle before relying on the percentage readout. The fuel gauge IC calibrates its coulomb counter against the new cell's discharge curve on that first cycle — skipping it leads to erratic percentage jumps for several days.

Why the Vodafone 354 reports wrong battery percentage after a cell swap

The 354 uses a fuel gauge IC that builds its state-of-charge model from the discharge curve of the original cell. When a new cell goes in, that learned curve no longer matches the physical cell in the bay. The IC then interpolates against stale data, showing percentages that jump or stall. One full discharge down to auto-shutdown followed by a complete charge resets the coulomb counter and re-anchors the gauge to the new cell. After that cycle, percentage tracking stabilises.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops below the modem's or display's sustained load threshold before the gauge reaches 0%. A fresh Li-ion cell with an uncalibrated fuel gauge reads 25% while actual cell voltage has already sagged to around 3.3V under screen-on modem load — the BMS cuts power to protect the cell. It is not a faulty battery. Run two full discharge-charge cycles and the gauge IC re-anchors its low-voltage threshold to the new cell's actual voltage floor, pushing the cutoff point back toward 5–8%.