About this replacement
Samsung SGH-L258 / SGH-L250 — 3.7V Li-ion Replacement Battery (AB553446BC)
This is a 3.7V, 700mAh Li-ion replacement battery for the Samsung SGH-L258, SGH-L250, SGH-CC03, SGH-B108, and over 20 additional Samsung candybar-style handsets from the mid-2000s era. It replaces OEM part numbers AB553446BC and AB553446BU. If the original cell no longer holds a charge or the phone shuts down unexpectedly, this is the direct swap.
- SGH-L258 / L250 platform fit: These models share the same battery bay dimensions (49.70 × 34.00 × 5.00mm), connector pinout, and 3.7V nominal rail. The BMS handshake on each uses the same ID resistor value, so the charge IC accepts this cell without reconfiguration.
- Bench tested on actual hardware: We cycled this cell through a full discharge and charge sequence on the SGH-L258. The BMS accepted the cell on first contact, the charge IC entered CC/CV mode correctly, and cut off at the expected terminal voltage without thermal events.
- Fuel gauge recalibration on first use: After installation, run one complete discharge down to auto-shutoff, then charge uninterrupted to 100% before regular use. The SGH-L250 series uses a simple coulomb counter with no active learning — skipping this cycle leaves the percentage readout calibrated to the old cell curve, not the new one.
Sudden shutdown at 20–30% on the SGH-L258 after cell replacement
A new Li-ion cell has a steeper voltage discharge curve than an aged original. When the SGH-L258's charge IC was calibrated to the old, degraded cell, it mapped 20–30% remaining to a voltage that the new cell actually hits much later in the discharge cycle. Under modem transmit or backlight load, the phone pulls enough current to cause a sharp voltage sag. If that sag drops the cell below the BMS cutoff threshold — typically around 3.0V — the phone shuts off even though the reported percentage looked safe. One full discharge-charge calibration cycle resets the coulomb counter reference and eliminates the premature cutoff.
Phone feels warm near the battery during the first charge
A new high-impedance cell converts more energy to heat during the initial charge cycle than a broken-in cell does. On the SGH-L258, the charge IC applies constant-current at roughly 350–700mA into a cell with higher internal resistance than the depleted original — that resistance generates heat. This is normal for the first one or two cycles and diminishes as the cell's internal resistance drops with use. If the handset remains hot to the touch after two full cycles, check that the battery contacts are clean and seated flush, as a poor contact forces the charge IC to compensate with higher voltage at the pins.