Samsung Galaxy S3 EB-L1H2LLU Replacement Battery 3.7V 4200mAh

NTT DoCoMo Galaxy S3 — 3.7V Li-ion 4200mAh Replacement Battery (EB-L1H2LLU)

This is a 3.7V, 4200mAh Li-ion replacement cell for the Samsung Galaxy S3 (Galaxy SIII) sold under the NTT DoCoMo network variant. It covers OEM part numbers EB-L1H2LLU, EB-L1H2LLD, SC07, and ASC29087. The extended 4200mAh capacity exceeds the stock cell, restoring full-day power to an aging handset.

• Galaxy S3 variant compatibility: The SC07 and ASC29087 part numbers confirm this cell covers the NTT DoCoMo market variant alongside the broader GT-I9300 series. All share the same 3.7V nominal rail, connector footprint, and BMS handshake, so one cell covers the full compatibility list.
• Bench tested on actual hardware: We cycled this cell on a GT-I9300 test unit through three full discharge-charge passes. The BMS accepted the charge IC handshake without fault codes on all three cycles, and the coulomb counter tracked within expected variance by cycle two.
• Fuel gauge recalibration after installation: On first use, disable fast charging and run one complete discharge-charge cycle at standard rate. The Galaxy S3 fuel gauge IC is calibrated to the old cell's discharge curve — a full slow cycle lets it map the new cell before resuming normal charge rates.

Why the Galaxy S3 reports wrong battery percentage after a cell swap

The Galaxy S3 uses a coulomb counter that builds its reference curve from the original cell's capacity history. When you drop in a new cell — especially one with higher capacity — the counter is still referencing the old curve. This causes the OS to display inflated or deflated percentages that bear little relation to actual charge state. The fix is one full discharge to auto-off, followed by a slow charge to 100% with fast charging disabled. After that cycle, the fuel gauge IC rewrites its reference and percentage readings stabilise.

Sudden shutdown at 20–30% on the replacement cell

This is a voltage cliff issue, not a capacity defect. Under heavy modem or screen load the cell voltage sags — if it dips below the BMS cutoff threshold (typically around 3.0V per cell) the phone shuts down even though the fuel gauge still shows charge remaining. It appears most often when the fuel gauge IC is still uncalibrated to the new cell's discharge curve. Run two full slow cycles to recalibrate the coulomb counter, and check that the phone is not in an area forcing constant high-power radio scanning, which accelerates voltage sag at low states of charge.