T-Mobile Galaxy Stratosphere II 4G Replacement Battery 3.7V 1500mAh

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

This is a 3.7V, 1500mAh Li-ion replacement battery for the Samsung Galaxy Stratosphere II 4G on T-Mobile's network. It fits the Galaxy Stratosphere II and Galaxy Stratosphere 2 variants. Swap it in when your original cell no longer holds a usable charge through a normal day.

• Stratosphere II variant compatibility: The Galaxy Stratosphere II, Stratosphere II 4G, and Stratosphere 2 all share the same battery bay dimensions (69.80 × 51.90 × 4.20mm), voltage rail, and connector pinout — one cell fits every variant in this lineup without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a Stratosphere II unit and confirmed the BMS handshake completed without fault flags. The protection circuit engaged correctly at low-voltage cutoff and did not trip during normal charge current.
• Fuel gauge recalibration on first install: On first use after installation, run one full discharge down to auto-shutoff, then charge uninterrupted to 100% before normal use. This gives the fuel gauge IC a complete discharge curve to map against the new cell — skipping this step is the primary cause of erratic percentage readings in the first few days.

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

The Stratosphere II's fuel gauge IC retains the discharge curve from the old, degraded cell. When you install a fresh cell, the IC has no accurate reference for where the new cell's voltage cliff sits. Under modem load — LTE data, a call, or screen-on with sync active — the cell voltage drops faster than the IC expects and the phone cuts out to protect the hardware. The fix is a full calibration cycle: discharge to auto-shutoff, then charge to 100% without interruption. After one complete cycle, the coulomb counter recalibrates and percentage readings stabilise.

Phone feels warm near the battery compartment during first charge after replacement

A new Li-ion cell typically has higher internal impedance than a broken-in cell. When the charge IC pushes current into a high-impedance cell, more energy is lost as heat — this is normal for the first one or two charge cycles and not a sign of a fault. Warmth should stay moderate and reduce noticeably by the second or third full charge. If the phone becomes hot to the touch or charge cuts off before 100%, remove the battery and check that it is seated flat with no bulge before proceeding.