Motorola V720 Replacement Battery 3.7V 750mAh Li-ion

Motorola V720 / V730 — 3.7V Li-ion Replacement Battery

This 3.7V 750mAh (2.78Wh) Li-ion cell replaces the original battery in the Motorola V720 and V730 flip phones. Both models share the same battery bay dimensions, connector pinout, and charge management circuit, so one cell covers both. Install it when the original no longer holds a charge or the phone shuts down unexpectedly.

• V720 and V730 shared platform: Motorola built both handsets on the same mid-2000s flip platform. The battery bay, locking tab geometry, and three-pin connector are identical across both models, so a single cell fits without modification.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge passes on a V720 unit. The charge IC accepted the cell without fault codes, and the BMS held voltage steady across both standby and active call loads.
• Fuel gauge recalibration on first use: On first installation, run one complete discharge down to auto-shutoff, then charge uninterrupted to 100% before use. The V720's fuel gauge IC calibrates its coulomb counter against this first full cycle — skipping it causes the percentage display to read inaccurately from the start.

Why the V720 reports wrong battery percentage after a cell swap

The V720 uses a basic fuel gauge IC that stores a discharge curve calibrated to the original cell. When a new cell goes in, that stored curve no longer matches the actual cell chemistry. The IC interpolates voltage readings against an old baseline, so it displays percentages that don't reflect true charge state. One full discharge-to-shutoff followed by an uninterrupted charge to 100% resets the baseline and brings the gauge back into accuracy.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops sharply under the load of an active call or backlight — a voltage cliff the fuel gauge didn't predict. The IC reads 25% on its stored curve but the actual cell voltage has already fallen below the BMS cutoff threshold. It's common on the first few cycles before the gauge recalibrates. Run two full discharge-charge cycles and the shutoffs should move to below 10%.