EB-L1D7IBA AT&T Skyrocket Replacement Battery 3.7V 1800mAh

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

This is a 3.7V, 1800mAh Li-ion replacement cell for the AT&T Skyrocket (SGH-I727), also sold as the Galaxy S II Skyrocket 4G. It uses the EB-L1D7IBA part number and drops into the same battery bay as the original Samsung cell. Capacity is rated at 1800mAh / 6.66Wh — matching the stock specification.

• SGH-I727 and Skyrocket 4G variants: These models share the same battery bay dimensions, connector pinout, and 3.7V nominal voltage rail. The BMS handshake on all listed variants reads the same cell identification lines, so one cell covers the full compatibility group.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the SGH-I727 platform. The BMS accepted charge from both the stock charger and USB, completed full charge termination cleanly, and held voltage within spec under screen-on and LTE radio load.
• Fuel gauge recalibration on first install: On first use after fitting this cell, run one complete discharge down to automatic shutoff, then charge uninterrupted to 100% before using the phone. The fuel gauge IC in the Skyrocket calibrates its coulomb counter against this first full cycle — skipping it leads to erratic percentage readings for the first several days.

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

The Skyrocket's fuel gauge IC stores a charge curve calibrated to the original cell. A new cell with a slightly different internal resistance profile causes the IC to misread state-of-charge under load. When the LTE modem or display draws a current spike, the actual cell voltage dips below the hardware protection threshold even though the gauge shows 20–30% remaining. The phone cuts power to protect the cell. One full discharge-to-shutoff cycle followed by an uninterrupted charge resets the coulomb counter against the new cell's actual curve and eliminates most of these events.

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

Li-ion cells self-discharge during storage. If this cell shipped or was stored for several months, its resting voltage may have dropped below 2.5V — the point where the BMS enters lockout mode to prevent deep-discharge damage. A phone that shows nothing on screen and doesn't respond to the power button is almost always in BMS lockout, not a dead phone. Connect the original or a known-good charger and leave it for 20–30 minutes without pressing anything. The charge IC will trickle current into the cell until voltage recovers past the BMS re-enable threshold, typically around 2.9–3.0V, after which the phone will boot normally.