About this replacement
Samsung SGH-G810 / SGH-D780 — 3.7V Li-ion Replacement Battery (AB474350DE)
This is a 3.7V, 1200mAh Li-ion replacement battery for the Samsung SGH-G810, SGH-D780, SGH-i550, and GT-i8510. It shares OEM part numbers AB474350DE and AB474350BE across these models. Dimensions are 52.50 × 42.10 × 4.20mm — confirm your original cell matches before fitting.
- Multi-model fitment explained: The SGH-G810, D780, i550, and GT-i8510 all run the same 3.7V battery rail with an identical connector footprint and BMS handshake protocol. Samsung sourced the cell under several part variants — AB474350BA, BC, BU, DU — all electrically identical, same physical envelope.
- Bench tested on actual hardware: We ran this cell through full charge and load cycles on the SGH-G810. The BMS accepted charge from a standard 4.2V-cutoff charger without fault flags. Discharge curves stayed flat through mid-range before the expected drop near cell floor.
- Fuel gauge recalibration on first cycle: After fitting this cell, disable any fast charging accessory for the first complete discharge-charge cycle. The phone's fuel gauge IC is calibrated to the old cell's discharge curve. One slow, full cycle lets the coulomb counter reset against the new cell's actual capacity before high-current charging begins.
Sudden shutdown at 20–30% on the SGH-G810 after a cell swap
This is a voltage cliff issue, not a capacity fault. When the modem fires a burst transmission or the screen peaks brightness, instantaneous current draw pulls the cell voltage below the BMS cutoff threshold — even if the fuel gauge still shows charge remaining. The old fuel gauge curve mapped a worn cell that sagged gradually; a new cell drops faster under the same load at that state of charge. Running one full discharge to around 3.4V and a complete recharge resets the coulomb counter and eliminates most of these premature shutoffs.
Phone shows erratic or frozen battery percentage after replacement
The SGH-G810's fuel gauge IC stores a learned discharge curve for the previous cell. A new cell with different internal resistance throws off that map immediately. You'll see the percentage jump several points in either direction or stick at one number for long stretches before dropping suddenly. Power the phone completely off, charge to 100% without interruption, then run it down to auto-shutdown in one session. After one full cycle the fuel gauge IC rewrites its reference curve against the new cell and percentage readings stabilise.