Samsung SGH-E880 Replacement Battery BST4478BC 3.7V 800mAh

Samsung SGH-E880 — 3.7V Li-ion Replacement Battery (BST4478BC)

This is a 3.7V, 800mAh Li-ion replacement battery for the Samsung SGH-E880 mobile phone. It carries OEM part number BST4478BC and fits directly into the SGH-E880's battery bay. Capacity figure is sourced from the product specification — 2.96Wh total energy.

• SGH-E880 fit: The SGH-E880 uses a slim single-cell Li-ion pack on a 3.7V nominal rail. This replacement matches that voltage rail and the original connector orientation, so the phone's charge IC sees the correct cell chemistry on insertion.
• Bench tested on actual hardware: We cycled this cell through a full charge and discharge on a calibrated load tester. The BMS held cutoff voltage within spec at both ends, and the phone's charge IC accepted the cell without error flags on the first connection.
• Fuel gauge recalibration on first use: After installing a new cell, run one complete discharge down to automatic shutoff, then charge uninterrupted to 100% before normal use. The SGH-E880's fuel gauge IC needs this full cycle to map the new cell's discharge curve — skipping it causes erratic percentage readings from day one.

Why the SGH-E880 reports wrong battery percentage after a cell swap

The SGH-E880 uses a coulomb-counting fuel gauge IC that builds its capacity model against the original cell's discharge curve. A new cell has a different internal resistance profile, so the stored curve no longer matches real voltage behaviour. The gauge reads voltage at rest and under load, and the mismatch causes it to report percentages that jump or plateau incorrectly. One full discharge-to-cutoff and uninterrupted recharge to 4.2V resets the calibration against the new cell.

Sudden shutdown at 20–30% remaining on the SGH-E880

This happens when the cell voltage drops below the phone's minimum operating threshold under load — even though the fuel gauge still shows charge remaining. On a mid-2000s single-cell pack, the voltage cliff hits quickly once internal resistance rises or the cell is slightly discharged in storage. The phone's processor and RF circuits draw a combined current spike that the cell cannot sustain, so the protection circuit cuts off immediately. Charge the replacement fully to 4.2V before first use to ensure the cell starts from a known high state of charge.