SNN5570 Motorola V120 Replacement Battery 3.7V 900mAh

Motorola V120 Series — 3.7V Li-ion Replacement Battery (SNN5570 / SNN5571A)

This is a 3.7V, 900mAh Li-ion cell for the Motorola V120, V120C, V120D, and V120e candybar-style mobile phones. It replaces OEM part numbers SNN5570 and SNN5571A. Physical dimensions are 55.44 × 35.48 × 9.57mm — confirm against your original before fitting.

• V120 series fit: The V120, V120C, V120D, and V120e share the same battery bay dimensions, connector pinout, and 3.7V nominal voltage rail. One cell fits all four variants without modification.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on a V120 handset. The BMS accepted the charge IC handshake cleanly from the first cycle, with no cutoff anomalies at either end of the voltage range.
• Fuel gauge recalibration on first use: After fitting, disable any fast-charge mode if available and run one full discharge-to-charge cycle before normal use. This lets the fuel gauge IC map the new cell's actual discharge curve before reporting percentages — skipping this step produces erratic readings on the status bar.

Why the V120 reports wrong battery percentage after a cell swap

The V120 uses a fuel gauge IC that builds a model of the cell's discharge curve over time. When you swap in a new cell, the IC still references the old, degraded curve it learned from the previous battery. The result is percentage figures that don't match actual charge state — often reading 100% while still charging, or dropping abruptly at the low end. One complete discharge-charge cycle forces the IC to recalibrate against the new cell's actual voltage response.

Sudden shutdown at 20–30% on the replacement cell

This happens when the modem fires up at full power during a call and pulls a brief current spike the cell can't sustain without the voltage rail sagging below the BMS cutoff threshold. It's not a faulty cell — it's the fuel gauge IC reporting remaining charge based on an uncalibrated curve, so the phone thinks it has 25% left when the cell is already close to its minimum voltage floor. Run two full calibration cycles and the gauge will begin cutting off the display percentage closer to the real voltage cliff. If shutdowns continue past 3.0V under load, measure resting voltage after a full charge — it should read 4.1–4.2V.