EB504465VJ SoftBank 940SC Replacement Battery 3.7V 1700mAh

SoftBank 940SC — 3.7V Li-ion Replacement Battery (EB504465VJ)

This is a 3.7V, 1700mAh Li-ion cell built to replace the original EB504465VJ battery in the SoftBank 940SC smartphone. It fits the 940SC only — do not assume cross-compatibility with other SoftBank handsets. Capacity is 1700mAh (6.29Wh), matching the original specification.

• 940SC battery fitment: The 940SC uses a fixed connector pinout and BMS handshake tied to the EB504465VJ cell spec. A replacement must match voltage, physical dimensions (64.60 × 43.90 × 5.20mm), and the BMS communication protocol — otherwise the phone's charge IC rejects the cell or reports incorrect state-of-charge.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the 940SC platform. The BMS accepted the cell without error flags, the charge IC reached termination voltage cleanly, and the fuel gauge IC tracked state-of-charge without erratic jumps after the first full cycle.
• Fuel gauge recalibration on first use: After installing this cell, disable fast charging and run one complete discharge-to-charge cycle at standard rate. This lets the fuel gauge IC map the new cell's discharge curve before the OS uses that data for percentage reporting — skipping this step causes inaccurate readings for the first several cycles.

Sudden shutdown at 20–30% on the 940SC after a cell swap

This is a voltage cliff problem. A new Li-ion cell has a steeper discharge curve than a degraded original — the fuel gauge IC is still calibrated to the old cell's curve and misreads remaining capacity. Under modem load or screen brightness spikes, the actual cell voltage drops below the BMS cutoff threshold even though the OS shows charge remaining. The fix is one full discharge cycle from 100% to automatic shutdown, followed by an uninterrupted charge to 100%, at standard charge rate with fast charging disabled. After that cycle, the coulomb counter recalibrates and shutdowns at false percentages stop.

Phone warm near the battery during the first charge after replacement

A new cell starts with higher internal impedance than a broken-in cell. The charge IC pushes current into that higher-impedance cell, which converts more energy to heat than usual. This is normal for the first one or two charge cycles and tapers off as the cell's impedance settles. If the device stays warm beyond the third full charge, check that the replacement cell is seated flat against the chassis with no gap — air space under the cell traps heat. Surface temperature above 40°C on the back cover during charging after cycle three warrants a closer look at the installation.