EB-L1D7IBA Replacement Battery for AT&T Galaxy S II Skyrocket 3.7V

AT&T Samsung Galaxy S II Skyrocket — 3.7V Li-ion Replacement Battery (EB-L1D7IBA)

This 3.7V Li-ion battery replaces the original cell in the Samsung Galaxy S II Skyrocket (SGH-I727) on AT&T's 4G LTE network. It carries a 2800mAh / 10.36Wh capacity and fits the full Skyrocket lineup including the Galaxy SII Skyrocket 4G. Drop-in fitment uses the original connector and BMS handshake points.

• SGH-I727 and Skyrocket 4G compatibility: All Skyrocket variants share the same battery bay dimensions, connector pinout, and BMS communication protocol — the same cell services all of them without modification.
• Bench tested on actual hardware: We ran this cell through full charge cycles on the SGH-I727 and confirmed the BMS accepted the charge handshake without fault codes, reaching 3.7V nominal at rest with stable current draw across modem-active states.
• Fuel gauge recalibration on first use: After installing this cell, disable any fast-charge accessory and run one complete discharge-to-charge cycle. This lets the phone's fuel gauge IC map its coulomb counter to the new cell's discharge curve before high-current charging begins.

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

The Skyrocket's fuel gauge IC retains the discharge curve of the old, degraded cell in memory. When the replacement cell hits a voltage point the IC associates with imminent cutoff, it signals a hard shutdown — even though actual charge remains. The fix is a full discharge to near-zero followed by a complete charge to 100%, repeated once or twice. After two full cycles the coulomb counter recalibrates and reported percentage aligns with true cell state.

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

Li-ion cells self-discharge during storage, and if the voltage drops below approximately 2.5V per cell the BMS enters lockout mode to prevent damage — the phone will show nothing when you press power. Connect the phone to a wall adapter, not a PC port, and leave it for 20–30 minutes before attempting to power on. The charge IC will trickle current into the cell until the BMS unlocks at around 2.9V. If the screen stays black past that point, confirm the charger is delivering at least 5V at 1A.