BoostMobile Transform Ultra Replacement Battery 3.7V 1200mAh EB484659VA

BoostMobile Transform Ultra / SPH-M930 — 3.7V Li-ion Replacement Battery (EB484659VA)

This is a 3.7V, 1200mAh Li-ion replacement battery for the BoostMobile Transform Ultra (SPH-M930) smartphone. It slots directly into the battery bay and restores power to calls, messaging, and apps. Capacity is sourced from product data at 4.44Wh — match the OEM part number EB484659VA before ordering.

• Transform Ultra / SPH-M930 fitment: Both model names reference the same hardware platform. They share an identical battery bay, connector pitch, and BMS handshake protocol — one cell covers both designations.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the SPH-M930 platform. The BMS accepted the new cell without fault codes, and charge termination triggered correctly at full voltage.
• Fuel gauge recalibration on first use: After installation, run one full discharge-to-charge cycle with fast charging disabled. This gives the fuel gauge IC time to map the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell.

Sudden shutdown at 20–30% on the Transform Ultra after a cell swap

This happens because the fuel gauge IC on the SPH-M930 is still running a discharge curve calibrated to the old, degraded cell. The new cell has a steeper voltage cliff under modem and screen load than the IC expects. The phone reads 25% but the actual cell voltage has already dropped below the shutdown threshold. One full discharge-charge cycle without fast charging lets the coulomb counter reset against the new cell's real capacity curve.

Device not powering on after the replacement battery sat in storage

Li-ion cells self-discharge in storage. If the cell voltage drops below roughly 2.5V, the BMS enters lockout to prevent damage and will not pass current to the phone. The phone shows nothing — no boot screen, no charge indicator. Connect the charger and leave it for 15–30 minutes without pressing power; the charge IC needs to trickle current into the cell above the BMS re-initialisation threshold before normal charging resumes.