Samsung GT-I1819 B450BU Replacement Battery 3.8V 2100mAh

Samsung GT-I1819 / SM-G730 Series — 3.8V Li-ion Replacement Battery (B450BU)

This is a 3.8V, 2100mAh Li-ion replacement battery for the Samsung GT-I1819, SM-G730, SM-G730A, and SM-G3518, among other compatible models. It matches the original B450BU cell spec and fits the same physical cavity. Dimensions are 59.65 × 52.02 × 4.80mm.

• GT-I1819 and SM-G730 series compatibility: These models share the same 3.8V battery bay, connector pinout, and BMS handshake protocol — which is why a single cell covers the full SM-G730 lineup alongside the GT-I1819. Swapping within this group requires no adapter or modification.
• Bench tested on actual hardware: We cycled this cell on an SM-G730A through charge, standby draw, and screen-on load. The BMS held stable voltage delivery across all three states and tripped no low-voltage cutoffs during discharge.
• Fuel gauge recalibration after install: On first use after fitting this cell, disable fast charging and run one complete discharge-charge cycle at standard rate. The fuel gauge IC in this handset calibrates its coulomb counter against the new cell's discharge curve — skipping this step causes percentage readings to drift immediately after installation.

Sudden shutdown at 20–30% on the SM-G730 after a cell swap

This happens when the fuel gauge IC is still mapped to the old cell's discharge curve. The new cell hits a voltage cliff under modem or screen load at a state-of-charge the gauge still reads as 20–30%. The phone interprets the voltage drop as a fault and shuts down before the gauge catches up. One full standard-rate discharge cycle down to automatic cutoff — then a full charge — resets the calibration baseline to the new cell.

Phone warm near the battery compartment on the first charge cycle

A new cell starts with higher internal impedance than a broken-in one. The charge IC pushes current into a cell that resists it more than usual, and that resistance converts to heat. This is normal during the first one or two charge cycles and reduces as impedance drops with use. If warmth persists past the third full charge, check that the charging port is clean and that the phone is not running background tasks during charging.