About this replacement
Sanyo SCP-7500 / MM-7500 Series — 3.7V Li-ion Replacement Battery
This is a 3.7V 1050mAh Li-ion battery for the Sanyo 7500, MM-7500, SCP7500, and RL7500 smartphones. It slots in where the original cell has degraded past the point of holding a usable charge. Voltage and physical dimensions match the OEM spec — 63.24 × 45.00 × 7.86mm.
- SCP7500 / MM-7500 / RL7500 platform fit: These four model numbers share the same battery bay dimensions, connector pinout, and 3.7V nominal voltage rail — one cell covers all four variants without modification.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on a calibrated rig. The BMS held cutoff correctly at both ends — no early shutoff, no overcharge bleed past 4.2V.
- Fuel gauge recalibration on first use: On first installation, disable fast charging if the option is available, then run one complete discharge-to-charge cycle. This gives the phone's fuel gauge IC a clean reference curve against the new cell before high-current charging begins on an uncalibrated state-of-charge register.
Sudden shutdown at 20–30% on the Sanyo 7500 after a cell swap
This happens because the fuel gauge IC is still referencing the discharge curve of the old, degraded cell. When the new cell hits a voltage point the old curve mapped to 20–30%, the phone treats it as a low-voltage event and cuts out — even though actual remaining capacity is higher. The modem radio and screen pulling simultaneous load accelerates the voltage sag enough to trip the threshold. One full discharge cycle to automatic shutdown, followed by a full charge, resets the coulomb counter and clears the fault.
Phone showing erratic percentage jumps after replacement
Percentage jumping — say, from 67% to 43% in minutes — is the fuel gauge IC actively recalibrating against an unfamiliar cell chemistry signature. The IC learned its lookup table from the worn original cell over many cycles. A new cell has a steeper, cleaner voltage curve, which the IC initially misreads. Run two full discharge-charge cycles without interrupting at partial charge. After the second full cycle, the reported percentage typically stabilises within a few percent of actual capacity.