Sprint MP6900 Replacement Battery 3.7V 1100mAh Li-ion

Sprint MP6900 — 3.7V Li-ion Replacement Battery (ELF0160)

This 3.7V Li-ion cell replaces the original battery in the Sprint MP6900 feature phone. Rated at 1100mAh (4.07Wh), it matches the stock voltage and form factor exactly. Dimensions are 51.53 × 37.36 × 5.35mm — same footprint as the OEM cell.

• MP6900 fit: The MP6900 draws from a single-cell 3.7V rail with a three-contact connector. This cell matches that contact layout and the BMS charge termination voltage the phone expects — the charge IC sees the same endpoint and cuts off correctly.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the MP6900 platform. The BMS accepted the cell without a handshake fault, and the charge IC reached full termination voltage without thermal events.
• Fuel gauge recalibration on first cycle: On first use after installation, run one complete discharge down to auto-shutdown, then charge to 100% without interruption. The MP6900's fuel gauge IC needs a full cycle against the new cell's discharge curve before percentage readings stabilise.

Why the MP6900 reports wrong battery percentage after a cell swap

The MP6900 uses a fuel gauge IC that tracks capacity by modelling the original cell's discharge curve. When you install a replacement cell, the IC is still calibrated to the old cell's internal resistance and voltage profile. Until it sees one full discharge-charge cycle on the new cell, the percentage readout is guessing. After one complete cycle — drain to shutdown, charge uninterrupted to 100% — the IC resets its model and reads accurately.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops sharply under load — screen backlight, radio polling, or a burst of processing pulls more current than the cell can sustain at that state of charge. The protection circuit trips before the percentage display reaches zero. It is not a defective cell — it is the fuel gauge IC cutting power at its voltage floor. Run one full calibration cycle first; if shutdowns continue, check that the battery contacts on the phone are clean and making firm contact, and verify the resting voltage reads above 3.6V after a full charge.