Vodafone 331 CAB3010010C1 Replacement Battery 3.7V 600mAh

Vodafone 331 / 541 Series — 3.7V Li-ion Replacement Battery (CAB3010010C1)

This is a 3.7V, 600mAh Li-ion battery for the Vodafone 331 and 541 series phones, including the VF331 and VF541 variants. It replaces OEM part numbers CAB3010010C1, CAB30B4000C1, CAB20G0000C1, and CAB30M0000C1. Fit this when the original cell no longer holds a usable charge or fails to power the handset through basic calls and messaging.

• 331 and 541 series compatibility: These models share the same 3.7V single-cell architecture, connector pinout, and BMS handshake protocol, which is why one cell covers both the 331 and 541 lines. The charge management IC expects the same communication from the battery regardless of which variant it sits in.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a 331 handset and confirmed the BMS accepted the cell without error flags. The protection circuit responded correctly to both low-voltage cutoff and full-charge termination.
• Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging and run one full discharge-charge cycle at standard rate. This lets the fuel gauge IC map the new cell's discharge curve before it begins reporting accurate percentages. Skipping this step causes erratic percentage readings for several days.

Why the Vodafone 331 shuts down suddenly at 20–30% after a cell swap

A fresh cell has a slightly different voltage-to-capacity curve than the original. The phone's fuel gauge IC was calibrated to the old, degraded cell, so it misreads the new cell's state of charge. When the modem fires up for a call or the screen brightness spikes, the phone draws more current than the gauge expects at that reported percentage. The voltage drops below the cutoff threshold and the handset shuts off even though the cell still has capacity remaining. One full discharge to auto-off followed by an uninterrupted charge to 100% resets the coulomb counter and resolves this.

Phone will not power on after the replacement cell sat in storage

Li-ion cells self-discharge over time, and a cell stored in a phone for several weeks can drop below 2.5V per cell — the threshold where the BMS locks out to prevent damage. The handset will show nothing on screen and will not respond to the charge cable immediately. Connect the phone to a low-current USB charger (a standard 5V 500mA port, not a fast charger) and leave it for 20–30 minutes without pressing the power button. Once the cell climbs back above 3.0V, the BMS releases and the phone will power on or show a charging indicator.