MetroPCS Pinnacle 2 Replacement Battery 3.7V 800mAh

MetroPCS Pinnacle 2 — 3.7V Li-ion Replacement Battery

This is a 3.7V Li-ion battery rated at 800mAh (2.96Wh) for the MetroPCS Pinnacle 2 smartphone. It replaces the original cell when the phone no longer holds charge, shuts down unexpectedly, or fails to power on. The battery matches the OEM voltage and form factor at 42.50 x 35.50 x 5.00mm.

• Pinnacle 2 cell fit: The Pinnacle 2 uses a compact 3.7V single-cell architecture. This replacement matches that voltage rail and physical footprint, so the battery connector seats without modification and the BMS communicates normally with the phone's charge IC.
• Bench tested on actual hardware: We cycled this cell through charge and discharge under modem-active and screen-on loads. The BMS held cutoff voltage correctly and did not trip under the brief current spikes that occur during call connection.
• Fuel gauge recalibration on first use: On first use after installation, run one complete discharge down to auto-shutdown, then charge uninterrupted to 100% before using the phone again. This lets the fuel gauge IC map the new cell's discharge curve and report accurate percentages from the start.

Sudden shutdown at 20–30% on the Pinnacle 2 after a cell swap

This is a voltage cliff problem, not a capacity problem. At low state of charge, the new cell's internal resistance causes the voltage to drop sharply under modem or screen load — faster than the old degraded cell the fuel gauge was calibrated to. The phone's protection circuit reads that voltage drop as a critical low and shuts down, even though the reported percentage looks safe. One full discharge-charge cycle recalibrates the coulomb counter and moves the shutdown trigger to the correct point on the new cell's curve.

Percentage jumping erratically after fitting the replacement cell

The Pinnacle 2's fuel gauge IC stores a learned discharge curve from the previous battery. When a new cell goes in, that stored curve no longer matches actual cell behavior, so the reported percentage skips or reads incorrectly — sometimes dropping 10% in seconds or jumping back up. This is not a fault with the replacement battery. Charge the phone to 100%, allow it to drain fully to auto-shutdown without interruption, then charge back to 100%. After that single calibration cycle, percentage tracking stabilises.