Vodafone 411 Replacement Battery 3.7V 750mAh Li-ion

Vodafone 411 / VF411 — 3.7V Li-ion Replacement Battery

This is a 3.7V, 750mAh Li-ion cell for the Vodafone 411 (VF411) mobile phone. It replaces a degraded original battery that no longer holds adequate charge for calls and messaging. Capacity is 2.78Wh — matching the original cell specification.

• 411 and VF411 compatibility: Both model designations share the same battery bay dimensions, connector pinout, and voltage rail. The cell measures 39.34 × 34.19 × 5.65mm — fit is confirmed against the physical battery compartment on both variants.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the 411 platform. The BMS accepted the cell without error flags, and the charge IC reached termination voltage cleanly with no premature cutoff.
• Fuel gauge recalibration on first cycle: After installing a new cell, run one full discharge to low battery warning, then charge uninterrupted to 100% before use. The 411's fuel gauge IC was calibrated to your old cell's discharge curve — this single cycle resets it to the new cell's characteristics.

Sudden shutdown at 20–30% on the Vodafone 411 after a cell swap

This is a voltage cliff issue. The fuel gauge IC reports remaining percentage based on a stored discharge curve, but a fresh cell has a steeper voltage drop under load — particularly when the modem transmits or the screen backlight peaks. The phone's low-voltage protection trips before the gauge catches up, causing an abrupt shutdown. One full discharge-charge cycle lets the coulomb counter recalibrate against the actual cell curve, and the shutdowns stop.

Vodafone 411 won't power on after sitting in storage with a flat battery

Li-ion cells that discharge below approximately 2.5V trigger a BMS lockout to prevent cell damage. If the phone has been stored flat for weeks or months, the BMS may refuse to pass current to the device. Connect to a charger and leave it for 15–20 minutes without pressing the power button — the charge IC needs time to trickle current into the cell and lift it above the BMS re-enable threshold. Once voltage recovers above roughly 3.0V, the phone will power on normally.