About this replacement
Mitsubishi Eclipse / MT450 — 3.7V Li-ion Replacement Battery (MA-0507)
This 3.7V, 900mAh Li-ion cell replaces the original battery in the Mitsubishi Eclipse, 450, and MT450 smartphones. It matches the OEM voltage rail and connector spec for these models. Capacity figure is sourced from product data — 900mAh, 3.33Wh.
- Eclipse / 450 / MT450 platform fit: These three models share the same battery bay geometry, connector pinout, and BMS handshake requirements — all confirmed against part number MA-0507 and WNP1155B3102 cross-reference data.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the MT450 platform. The BMS accepted the cell on first insertion, charge termination triggered correctly at 4.2V, and no overcurrent flags were raised during the discharge phase.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before it locks in percentage readings for daily use.
Sudden shutdown at 20–30% on the Eclipse after a cell swap
A new Li-ion cell has a slightly different voltage-versus-capacity curve than the worn cell the fuel gauge IC was calibrated against. When the phone hits a steep voltage drop under modem or screen load, the IC reads that drop as a critically low state and triggers a protective shutdown — even though the coulomb counter still shows 20–30%. The fix is one full discharge-charge cycle without fast charging active. After that cycle, the fuel gauge IC resets its endpoint reference and the shutdowns stop. Confirm recovery by checking that the phone reaches at least 4.15V at the "100%" reading.
Phone feels warm near the battery during the first few charges
A new cell starts with higher internal impedance than a broken-in one. The charge IC pushes current into that higher-resistance cell, and the extra energy dissipates as heat in the battery bay. This is normal for the first two to three cycles and diminishes as the cell's impedance drops. If warmth persists beyond three full charge cycles, or the phone becomes hot rather than warm, stop charging and check that the charge IC is not locked in a fast-charge mode — drop to a 5V/1A standard charger and retest.