Sprint SCH-M580 Replacement Battery 3.7V 1700mAh Li-ion

Sprint SCH-M580 / Replenish / SPH-M930 — 3.7V Li-ion Replacement Battery

This 3.7V, 1700mAh Li-ion cell replaces the original battery in the Sprint SCH-M580, Replenish, and SPH-M930 smartphones. All three models share the same battery compartment dimensions and connector, making this a direct swap across the platform. Capacity is drawn from the product specification at 1700mAh (6.29Wh).

• SCH-M580, Replenish, and SPH-M930 platform fit: These three Sprint handsets share the same physical cell footprint at 64.60 × 43.90 × 5.20mm, the same 3.7V nominal voltage rail, and the same three-contact connector layout — so one cell covers all three without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench, confirming the BMS holds charge acceptance without triggering an early cutoff and that voltage stays stable under the combined load of the modem radio and display.
• Fuel gauge recalibration on first install: After fitting this cell, run one complete discharge down to the automatic shutdown point, then charge fully without interruption. This gives the fuel gauge IC on the SCH-M580 a clean reference curve against the new cell before it starts reporting percentages to the OS.

Sudden shutdown at 20–30% on the SCH-M580 after a cell swap

The SCH-M580's fuel gauge IC was calibrated to the discharge curve of the original cell. A new cell has a different impedance profile, so the IC misjudges how much capacity remains. Under the combined load of the modem and screen, the voltage drops below the BMS cutoff threshold faster than the gauge expects — the phone sees a sudden cliff and shuts down even though the percentage reads non-zero. One full uninterrupted discharge-to-shutdown followed by a full charge resets the coulomb counter reference. After that cycle, shutdowns in the 20–30% range stop occurring.

Battery percentage jumping erratically in the first few days after replacement

Erratic percentage readings — jumping from 45% to 70% or dropping 15 points in a few minutes — are a fuel gauge IC recalibration symptom, not a faulty cell. The gauge is still mapping its internal model against the actual discharge curve of the new 1700mAh cell. Avoid partial charges during this period; each interrupted cycle extends the time it takes the IC to build an accurate curve. Complete two full discharge-charge cycles and the percentage display stabilises.