Alcatel OT-BY30 Replacement Battery 3.7V 700mAh

Alcatel OT-V770 / One Touch V770 Series — 3.7V Li-ion Replacement Battery (OT-BY30)

This is a 3.7V, 700mAh Li-ion replacement battery for the Alcatel OT-V770, OT-V770A, One Touch V770, and One Touch V770A. It replaces OEM part numbers OT-BY30, T5001664AAAA, CAB30C0000C1, and B-Lava. Physical dimensions are 52.50 × 38.45 × 4.10mm — measure your existing cell before fitting.

• OT-V770 and V770A compatibility: Both the OT-V770 and V770A share the same battery bay geometry, connector pinout, and 3.7V nominal voltage rail. One cell covers both variants without modification.
• Bench tested on actual hardware: We ran charge and discharge cycles through a full capacity check. The BMS held the charge termination voltage correctly and did not trip under the low-current draw typical of this handset's modem and display stack.
• Fuel gauge recalibration on first use: After fitting this cell, disable any fast-charge mode and run one full discharge-to-charge cycle before normal use. This lets the phone's fuel gauge IC map its coulomb counter against the new cell's actual discharge curve — skipping this step is the main reason percentage readings jump erratically in the first few days.

Why the OT-V770 reports wrong battery percentage after a cell swap

The phone's fuel gauge IC stores a learned discharge curve from the original cell. When a new cell goes in, the IC is still reading against that old curve, so the percentage on screen does not match actual charge state. The fix is one complete discharge down to auto-shutoff, followed by an uninterrupted charge to 100% with the phone off or idle. After that single cycle, the IC resets its reference points and percentage accuracy returns to normal.

Sudden shutdown at 20–30% on the replacement cell

This happens when the fuel gauge IC has not yet recalibrated and the cell hits a voltage cliff — the real cell voltage drops below the modem's minimum operating threshold before the screen shows 0%. The phone cuts power to protect the circuit even though the display still showed charge remaining. Run the full recalibration cycle described above. If shutdowns continue past the second cycle, check that the battery connector is fully seated — a partial contact raises internal resistance and accelerates voltage sag under load, triggering BMS cutoff earlier than expected. Target resting voltage after a full charge should read 4.1–4.2V at the connector pins.