Galaxy Stratosphere II 4G Replacement Battery 3.7V 1500mAh

Verizon Galaxy Stratosphere II 4G — 3.7V Li-ion Replacement Battery

This is a 3.7V, 1500mAh Li-ion replacement battery for the Verizon Galaxy Stratosphere II 4G (SCH-I415 / SCHI415SAV). It slots into the standard battery bay and connects to the phone's charge and fuel gauge circuits. Capacity matches the original cell at 5.55Wh.

• SCH-I415 platform fit: The Stratosphere II runs a single-cell 3.7V rail shared across the QWERTY keyboard backlight, LTE modem, and display. Any replacement cell must hold voltage under combined modem and display load — this cell meets that requirement without connector modification.
• Bench tested on actual hardware: We ran the cell through charge-discharge cycles on an SCH-I415 unit. The BMS accepted charge immediately, the fuel gauge IC tracked state-of-charge without spurious jumps, and the protection circuit tripped correctly at low-voltage cutoff.
• Fuel gauge recalibration on first use: After installing this cell, disable fast charging and run one complete discharge-to-charge cycle before normal use. The phone's fuel gauge IC is calibrated against the old cell's discharge curve — one full cycle resets the coulomb counter to the new cell and prevents erratic percentage readings.

Sudden shutdown at 20–30% on the Stratosphere II after a cell swap

The Stratosphere II's LTE modem pulls hard current spikes during handoff events. If the fuel gauge IC still holds calibration data from the degraded original cell, it can report 25% remaining while the actual cell voltage has already dropped below the modem's minimum operating threshold — around 3.4V under load. The phone cuts power to protect the circuit before the display percentage reaches zero. One full discharge-charge cycle after installation forces the coulomb counter to rebuild its reference table against the new cell, and the premature shutdowns stop.

Phone won't power on after the replacement battery sat in storage

Li-ion cells self-discharge during storage. If the voltage drops below approximately 2.5V per cell, the BMS enters lockout mode and blocks charge input to prevent damage from deep-discharge recovery. Plugging the phone in shows nothing on screen. Connect the phone to a wall adapter — not a USB port — and leave it for 20–30 minutes without pressing the power button. The charge IC needs time to trickle current past the BMS lockout threshold before the phone will respond to a boot attempt.