Samsung Galaxy S III Replacement Battery EB-L1G6LLUC 3.8V 2100mAh

Samsung Galaxy S III GT-I9300 — 3.8V Li-ion Replacement Battery (EB-L1G6LLUC)

This 3.8V, 2100mAh Li-ion cell replaces the original battery in the Samsung Galaxy S III and its variants, including the GT-I9300, GT-I9308, and SHW-M440S. It matches the OEM voltage rail and physical dimensions (63.20 × 50.40 × 5.40mm) for a correct fit under the rear cover. Capacity is 2100mAh — 7.98Wh — matching the factory specification.

• GT-I9300 and variant compatibility: The GT-I9300, GT-I9308, SHW-M440S, and Galaxy S III LTE share the same battery bay dimensions, 3.8V supply rail, and connector pinout. All run off the same EB-L1G6LLUC cell specification, so one part number covers the platform.
• Bench tested on actual hardware: We cycled this cell on a GT-I9300 unit and monitored BMS cutoff behaviour through charge termination. The protection circuit tripped correctly at the 4.2V upper limit and held low-voltage cutoff at 3.0V without false trips during modem-load spikes.
• Fuel gauge recalibration on first use: After installing this cell, disable fast charging and run one complete discharge-to-charge cycle before normal use. The Galaxy S III's fuel gauge IC is calibrated against the old cell's discharge curve — one full cycle lets it re-map against the new cell before resuming high-current input.

Why the GT-I9300 reports wrong battery percentage after a cell swap

The Galaxy S III uses a coulomb-counter fuel gauge IC that builds its capacity model from previous charge-discharge data. When the cell is swapped, the IC carries over the old cell's learned curve. The displayed percentage drifts from actual state-of-charge because the IC is referencing voltage-to-capacity mapping that no longer matches the new cell. One full discharge to automatic shutdown, followed by a full charge to 100%, forces the IC to rewrite its reference table against the replacement cell.

Sudden shutdown at 20–30% battery remaining on the replacement cell

This is a voltage-cliff failure, not a capacity problem. Under combined modem, display, and processor load, cell voltage sags sharply below what the fuel gauge predicted at that state-of-charge. The phone's protection circuit triggers shutdown before the displayed percentage reaches zero. The fix is the same calibration cycle — one full drain and charge — so the fuel gauge IC learns the actual voltage sag curve of the new cell. After calibration, shutdowns before 15% should stop.