Mitsubishi Trium 3HR-5/3AAAU Replacement Battery 3.6V 900mAh

Mitsubishi Trium / GEO / Astral Series — 3.6V Ni-MH Replacement Battery (3HR-5/3AAAU)

This is a 3.6V, 900mAh Ni-MH replacement battery for the Mitsubishi Trium, GEO, Astral, Galaxy, and compatible models. It replaces OEM part numbers 3HR-5/3AAAU, BW-14091420, and FZA-0001A. The cell fits the battery bay directly and restores the phone's ability to power up, hold a call, and run basic functions.

• Trium platform compatibility: The Trium, GEO, Astral, and Galaxy share the same 3.6V three-cell Ni-MH pack format and connector pinout. All models on this list draw from the same voltage rail and accept the same mechanical form factor — no adapter or modification needed.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on a Trium handset. The charge IC accepted the cell without fault flags, and voltage held steady under active call load across multiple cycles.
• Ni-MH first-cycle conditioning: Unlike Li-ion, this Ni-MH cell benefits from a slow first charge at the phone's standard rate — avoid using an external rapid charger on the first cycle. This lets the cell reach full capacity and prevents early memory effect from an incomplete initial charge.

Why the Trium reports wrong battery percentage after a cell swap

The Trium's fuel gauge IC builds its discharge curve against the original cell's internal resistance and capacity profile. A new cell has a different impedance, so the gauge reads the voltage incorrectly and reports inaccurate percentages from the first charge. This corrects itself after one complete discharge down to auto-shutoff followed by a full uninterrupted charge. After that cycle, the gauge recalibrates its reference points against the new cell's actual curve.

Phone shuts down suddenly at 20–30% on the replacement cell

Ni-MH cells have a steeper voltage drop curve at lower states of charge compared to Li-ion. When the Trium's modem fires during a call or SMS send, the current draw causes a brief voltage sag — if the cell is below roughly 30% capacity, that sag can cross the shutdown threshold before the gauge registers it. This is not a faulty cell; it means the fuel gauge IC has not yet mapped the new cell's voltage cliff. Run one full discharge-to-shutoff cycle and recharge to 100% — the cutoff behaviour will stabilise at 3.6V nominal.